9 years agotracing: use timestamp to determine start of latency traces
Steven Rostedt [Tue, 1 Sep 2009 15:06:29 +0000]
tracing: use timestamp to determine start of latency traces

Currently the latency tracers reset the ring buffer. Unfortunately
if a commit is in process (due to a trace event), this can corrupt
the ring buffer. When this happens, the ring buffer will detect
the corruption and then permanently disable the ring buffer.

The bug does not crash the system, but it does prevent further tracing
after the bug is hit.

Instead of reseting the trace buffers, the timestamp of the start of
the trace is used instead. The buffers will still contain the previous
data, but the output will not count any data that is before the
timestamp of the trace.

Note, this only affects the static trace output (trace) and not the
runtime trace output (trace_pipe). The runtime trace output does not
make sense for the latency tracers anyway.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: remove users of tracing_reset
Steven Rostedt [Fri, 4 Sep 2009 16:12:39 +0000]
tracing: remove users of tracing_reset

The function tracing_reset is deprecated for outside use of trace.c.

The new function to reset the the buffers is tracing_reset_online_cpus.

The reason for this is that resetting the buffers while the event
trace points are active can corrupt the buffers, because they may
be writing at the time of reset. The tracing_reset_online_cpus disables
writes and waits for current writers to finish.

This patch replaces all users of tracing_reset except for the latency
tracers. Those changes require more work and will be removed in the
following patches.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: disable buffers and synchronize_sched before resetting
Steven Rostedt [Fri, 4 Sep 2009 16:02:35 +0000]
tracing: disable buffers and synchronize_sched before resetting

Resetting the ring buffers while traces are happening can corrupt
the ring buffer and disable it (no kernel crash to worry about).

The safest thing to do is disable the ring buffers, call synchronize_sched()
to wait for all current writers to finish and then reset the buffer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: disable update max tracer while reading trace
Steven Rostedt [Tue, 1 Sep 2009 02:32:27 +0000]
tracing: disable update max tracer while reading trace

When reading the tracer from the trace file, updating the max latency
may corrupt the output. This patch disables the tracing of the max
latency while reading the trace file.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: print out start and stop in latency traces
Steven Rostedt [Wed, 2 Sep 2009 16:27:41 +0000]
tracing: print out start and stop in latency traces

During development of the tracer, we would copy information from
the live tracer to the max tracer with one memcpy. Since then we
added a generic ring buffer and we handle the copies differently now.
Unfortunately, we never copied the critical section information, and
we lost the output:

 #  => started at: kmem_cache_alloc
 #  => ended at:   kmem_cache_alloc

This patch adds back the critical start and end copying as well as
removes the unused "trace_idx" and "overrun" fields of the
trace_array_cpu structure.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: disable all cpu buffers when one finds a problem
Steven Rostedt [Thu, 3 Sep 2009 23:53:46 +0000]
ring-buffer: disable all cpu buffers when one finds a problem

Currently the way RB_WARN_ON works, is to disable either the current
CPU buffer or all CPU buffers, depending on whether a ring_buffer or
ring_buffer_per_cpu struct was passed into the macro.

Most users of the RB_WARN_ON pass in the CPU buffer, so only the one
CPU buffer gets disabled but the rest are still active. This may
confuse users even though a warning is sent to the console.

This patch changes the macro to disable the entire buffer even if
the CPU buffer is passed in.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: do not count discarded events
Steven Rostedt [Thu, 3 Sep 2009 14:23:58 +0000]
ring-buffer: do not count discarded events

The latency tracers report the number of items in the trace buffer.
This uses the ring buffer data to calculate this. Because discarded
events are also counted, the numbers do not match the number of items
that are printed. The ring buffer also adds a "padding" item to the
end of each buffer page which also gets counted as a discarded item.

This patch decrements the counter to the page entries on a discard.
This allows us to ignore discarded entries while reading the buffer.

Decrementing the counter is still safe since it can only happen while
the committing flag is still set.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: remove ring_buffer_event_discard
Steven Rostedt [Thu, 3 Sep 2009 19:33:41 +0000]
ring-buffer: remove ring_buffer_event_discard

The function ring_buffer_event_discard can be used on any item in the
ring buffer, even after the item was committed. This function provides
no safety nets and is very race prone.

An item may be safely removed from the ring buffer before it is committed
with the ring_buffer_discard_commit.

Since there are currently no users of this function, and because this
function is racey and error prone, this patch removes it altogether.

Note, removing this function also allows the counters to ignore
all discarded events (patches will follow).

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: fix ring_buffer_read crossing pages
Steven Rostedt [Thu, 3 Sep 2009 14:02:09 +0000]
ring-buffer: fix ring_buffer_read crossing pages

When the ring buffer uses an iterator (static read mode, not on the
fly reading), when it crosses a page boundery, it will skip the first
entry on the next page. The reason is that the last entry of a page
is usually padding if the page is not full. The padding will not be
returned to the user.

The problem arises on ring_buffer_read because it also increments the
iterator. Because both the read and peek use the same rb_iter_peek,
the rb_iter_peak will return the padding but also increment to the next
item. This is because the ring_buffer_peek will not incerment it
itself.

The ring_buffer_read will increment it again and then call rb_iter_peek
again to get the next item. But that will be the second item, not the
first one on the page.

The reason this never showed up before, is because the ftrace utility
always calls ring_buffer_peek first and only uses ring_buffer_read
to increment to the next item. The ring_buffer_peek will always keep
the pointer to a valid item and not padding. This just hid the bug.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: remove unnecessary cpu_relax
Steven Rostedt [Thu, 3 Sep 2009 14:12:13 +0000]
ring-buffer: remove unnecessary cpu_relax

The loops in the ring buffer that use cpu_relax are not dependent on
other CPUs. They simply came across some padding in the ring buffer and
are skipping over them. It is a normal loop and does not require a
cpu_relax.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: do not swap buffers during a commit
Steven Rostedt [Wed, 2 Sep 2009 14:56:15 +0000]
ring-buffer: do not swap buffers during a commit

If a commit is taking place on a CPU ring buffer, do not allow it to
be swapped. Return -EBUSY when this is detected instead.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoring-buffer: do not reset while in a commit
Steven Rostedt [Wed, 2 Sep 2009 13:59:48 +0000]
ring-buffer: do not reset while in a commit

The callers of reset must ensure that no commit can be taking place
at the time of the reset. If it does then we may corrupt the ring buffer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing/filters: Defer pred allocation
Li Zefan [Mon, 31 Aug 2009 08:49:41 +0000]
tracing/filters: Defer pred allocation

init_preds() allocates about 5392 bytes of memory (on x86_32) for
a TRACE_EVENT. With my config, at system boot total memory occupied
is:

5392 * (642 + 15) == 3459KB

642 == cat available_events | wc -l
15 == number of dirs in events/ftrace

That's quite a lot, so we'd better defer memory allocation util
it's needed, that's when filter is used.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4A9B8EA5.6020700@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

9 years agoMerge branch 'tip/tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git...
Ingo Molnar [Sat, 29 Aug 2009 11:06:05 +0000]
Merge branch 'tip/tracing/core' of git://git./linux/kernel/git/rostedt/linux-2.6-trace into tracing/core

9 years agotracing: Fix double CPP substitution in TRACE_EVENT_FN
Frederic Weisbecker [Thu, 27 Aug 2009 22:50:06 +0000]
tracing: Fix double CPP substitution in TRACE_EVENT_FN

TRACE_EVENT_FN relays on TRACE_EVENT by reprocessing its parameters
into the ftrace events CPP macro. This leads to a double substitution
in some cases.

For example, a bad consequence is a format always prefixed by
"%s, %s\n" for every TRACE_EVENT_FN based events.

Eg:
cat /debug/tracing/events/syscalls/sys_enter/format
[...]
print fmt: "%s, %s\n", "\"NR %ld (%lx, %lx, %lx, %lx, %lx, %lx)\"",\
"REC->id, REC->args[0], REC->args[1], REC->args[2], REC->args[3],\
REC->args[4], REC->args[5]"

This creates a failure in post-processing tools such as perf trace or
trace-cmd.

Then drop this double substitution and replace it by a new __cpparg()
macro that relays CPP arguments containing commas.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Josh Stone <jistone@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <1251413406-6704-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

9 years agoMerge branch 'tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic...
Ingo Molnar [Fri, 28 Aug 2009 11:53:07 +0000]
Merge branch 'tracing/core' of git://git./linux/kernel/git/frederic/random-tracing into tracing/core

9 years agotracing: only show tracing_max_latency when latency tracer configured
Steven Rostedt [Thu, 27 Aug 2009 20:52:21 +0000]
tracing: only show tracing_max_latency when latency tracer configured

The tracing_max_latency file should only be present when one of the
latency tracers ({preempt|irqs}off, wakeup*) are enabled.

This patch also removes tracing_thresh when latency tracers are not
enabled, as well as compiles out code that is only used for latency
tracers.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: remove legacy select of MARKERS by context switch tracing
Steven Rostedt [Thu, 27 Aug 2009 02:23:52 +0000]
tracing: remove legacy select of MARKERS by context switch tracing

The context switch tracer was made before tracepoints were mature, and
the original version used markers. This is no longer true and this
patch removes the select.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: Undef TRACE_EVENT_FN between trace events headers inclusion
Frederic Weisbecker [Thu, 27 Aug 2009 16:17:34 +0000]
tracing: Undef TRACE_EVENT_FN between trace events headers inclusion

The recent commit:

tracing/events: fix the include file dependencies

fixed a file dependency problem while including more than
one trace event header file.

This fix undefined TRACE_EVENT after an event header macro
preprocessing in order to make tracepoint.h able to correctly declare
the tracepoints necessary for the next event header file.

But now we also need to undefine TRACE_EVENT_FN at the end of an event
header file preprocessing for the same reason.

This fixes the following build error:

In file included from include/trace/events/napi.h:5,
                 from net/core/net-traces.c:28:
include/linux/tracepoint.h:285:1: warning: "TRACE_EVENT_FN" redefined
In file included from include/trace/define_trace.h:61,
                 from include/trace/events/skb.h:40,
                 from net/core/net-traces.c:27:
include/trace/ftrace.h:50:1: warning: this is the location of the previous definition
In file included from include/trace/events/napi.h:5,
                 from net/core/net-traces.c:28:
include/linux/tracepoint.h:285:1: warning: "TRACE_EVENT_FN" redefined
In file included from include/trace/define_trace.h:61,
                 from include/trace/events/skb.h:40,
                 from net/core/net-traces.c:27:
include/trace/ftrace.h:50:1: warning: this is the location of the previous definition

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <20090827161732.GA7618@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

9 years agotracing: Remove FTRACE_SYSCALL_MAX definitions
Jason Baron [Mon, 24 Aug 2009 21:40:26 +0000]
tracing: Remove FTRACE_SYSCALL_MAX definitions

Remove the FTRACE_SYSCALL_MAX definitions now that we have converted the
syscall event tracing code to use NR_syscalls.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Josh Stone <jistone@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anwin <hpa@zytor.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <f2240cdc8f0b1ca7617390c8f5ec90ba2bd348cf.1251146513.git.jbaron@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agotracing: Convert event tracing code to use NR_syscalls
Jason Baron [Mon, 24 Aug 2009 21:40:22 +0000]
tracing: Convert event tracing code to use NR_syscalls

Convert the syscalls event tracing code to use NR_syscalls, instead of
FTRACE_SYSCALL_MAX. NR_syscalls is standard accross most arches, and
reduces code confusion/complexity.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Josh Stone <jistone@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anwin <hpa@zytor.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <9b4f1a84ecae57cc6599412772efa36f0d2b815b.1251146513.git.jbaron@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agotracing: Define NR_syscalls for x86_64
Jason Baron [Wed, 26 Aug 2009 16:09:10 +0000]
tracing: Define NR_syscalls for x86_64

Express the available number of syscalls in a standard way by defining
NR_syscalls.

The common way to define it is to place its definition in asm/unistd.h
However, the number of syscalls is defined using __NR_syscall_max in
x86-64 after building a dynamic header file "asm-offsets.h"

The source file that generates this header, asm-offsets-64.c includes
unistd.h, then if we want to express NR_syscalls from __NR_syscall_max
in unistd.h only after generating the dynamic header file, we need a
watchguard.

If unistd.h is included from asm-offsets-64.c, then we are generating
asm-offset.h which defines __NR_syscall_max. At this time, we don't
want to (we can't) define NR_syscalls, then we do nothing.
Otherwise we define NR_syscalls because we know asm-offsets.h has
been generated.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Josh Stone <jistone@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anwin <hpa@zytor.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <20090826160910.GB2658@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agotracing: Define NR_syscalls for x86 (32)
Jason Baron [Mon, 24 Aug 2009 21:40:14 +0000]
tracing: Define NR_syscalls for x86 (32)

Add a NR_syscalls #define for x86. This is used in the syscall events
tracing code. Todo: make it dynamic like x86_64.

NR_syscalls is the usual name used to determine the number of syscalls
supported by the current arch. We want to unify the use of this number
across archs that support the syscall tracing. This also prepare to move
some of the arch code to core code in the syscall tracing area.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Josh Stone <jistone@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anwin <hpa@zytor.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <0f33c0f96d198fccc3ddd9ff7f5334ff5cb42706.1251146513.git.jbaron@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agotracing: Don't trace kernel thread syscalls
Hendrik Brueckner [Tue, 25 Aug 2009 16:02:37 +0000]
tracing: Don't trace kernel thread syscalls

Kernel threads don't call syscalls using the sysenter/sysexit
path. Instead they directly call the sys_* or do_* functions
that implement the syscalls inside the kernel.

The current syscall tracepoints only bind the sysenter/sysexit
path, then it has no effect to trace the kernel thread calls
to syscalls in that path.
Setting the TIF_SYSCALL_TRACEPOINT flag is then useless for these.

Actually there is only one case when a kernel thread can reach the
usual syscall exit tracing path: when we create a kernel thread, the
child comes to ret_from_fork and is the fork() return is then traced.
But this information alone is useless, then we don't want to set the
TIF flags for these threads.

Kernel threads have task_struct->mm set to NULL.
(Thanks to Heiko for that hint ;-)
The idea is then to check the mm field in syscall_regfunc() and
set the flag accordingly.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
LKML-Reference: <20090825160237.GG4639@cetus.boeblingen.de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agotracing: Check invalid syscall nr while tracing syscalls
Hendrik Brueckner [Tue, 25 Aug 2009 12:50:27 +0000]
tracing: Check invalid syscall nr while tracing syscalls

Most arch syscall_get_nr() implementations returns -1 if the syscall
number is not valid.  Accessing the bit field without a check might
result in a kernel oops (at least I saw it on s390 for ftrace selftest).

Before this change, this problem did not occur, because the invalid
syscall number (-1) caused syscall_nr_to_meta() to return NULL.

There are at least two scenarios where syscall_get_nr() can return -1:

1. For example, ptrace stores an invalid syscall number, and thus,
   tracing code resets it.
   (see do_syscall_trace_enter in arch/s390/kernel/ptrace.c)

2. The syscall_regfunc() (kernel/tracepoint.c) sets the
   TIF_SYSCALL_FTRACE (now: TIF_SYSCALL_TRACEPOINT) flag for all threads
   which include kernel threads.
   However, the ftrace selftest triggers a kernel oops when testing
   syscall trace points:
      - The kernel thread is started as ususal (do_fork()),
      - tracing code sets TIF_SYSCALL_FTRACE,
      - the ret_from_fork() function is triggered and starts
ftrace_syscall_exit() with an invalid syscall number.

To avoid these scenarios, I suggest to check the syscall_nr.

For instance, the ftrace selftest fails for s390 (with config option
CONFIG_FTRACE_SYSCALLS set) and produces the following kernel oops.

Unable to handle kernel pointer dereference at virtual kernel address 2000000000

Oops: 0038 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 Not tainted 2.6.31-rc6-next-20090819-dirty #18
Process kthreadd (pid: 818, task: 000000003ea207e8, ksp: 000000003e813eb8)
Krnl PSW : 0704100180000000 00000000000ea54c (ftrace_syscall_exit+0x58/0xdc)
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0 EA:3
Krnl GPRS: 0000000000000000 00000000000e0000 ffffffffffffffff 20000000008c2650
           0000000000000007 0000000000000000 0000000000000000 0000000000000000
           0000000000000000 0000000000000000 ffffffffffffffff 000000003e813d78
           000000003e813f58 0000000000505ba8 000000003e813e18 000000003e813d78
Krnl Code: 00000000000ea540: e330d0000008       ag      %r3,0(%r13)
           00000000000ea546: a7480007           lhi     %r4,7
           00000000000ea54a: 1442               nr      %r4,%r2
          >00000000000ea54c: e31030000090       llgc    %r1,0(%r3)
           00000000000ea552: 5410d008           n       %r1,8(%r13)
           00000000000ea556: 8a104000           sra     %r1,0(%r4)
           00000000000ea55a: 5410d00c           n       %r1,12(%r13)
           00000000000ea55e: 1211               ltr     %r1,%r1
Call Trace:
([<0000000000000000>] 0x0)
 [<000000000001fa22>] do_syscall_trace_exit+0x132/0x18c
 [<000000000002d0c4>] sysc_return+0x0/0x8
 [<000000000001c738>] kernel_thread_starter+0x0/0xc
Last Breaking-Event-Address:
 [<00000000000ea51e>] ftrace_syscall_exit+0x2a/0xdc

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
LKML-Reference: <20090825125027.GE4639@cetus.boeblingen.de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agotracing: Add syscall tracepoints - s390 arch update
Hendrik Brueckner [Tue, 25 Aug 2009 12:31:11 +0000]
tracing: Add syscall tracepoints - s390 arch update

This patch includes s390 arch updates to synchronize with latest
core changes in the syscalls tracing area.

- tracing: Map syscall name to number (syscall_name_to_nr())
- tracing: Call arch_init_ftrace_syscalls at boot
- tracing: add support tracepoint ids (set_syscall_{enter,exit}_id())

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
LKML-Reference: <20090825123111.GD4639@cetus.boeblingen.de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

9 years agoMerge branch 'tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic...
Ingo Molnar [Wed, 26 Aug 2009 06:29:02 +0000]
Merge branch 'tracing/core' of git://git./linux/kernel/git/frederic/random-tracing into tracing/core

Conflicts:
include/linux/tracepoint.h

Signed-off-by: Ingo Molnar <mingo@elte.hu>

9 years agotracing: add comments to explain TRACE_EVENT out of protection
Steven Rostedt [Wed, 26 Aug 2009 04:32:37 +0000]
tracing: add comments to explain TRACE_EVENT out of protection

The commit:
  commit 5ac35daa9343936038a3c9c4f4d6d3fe6a2a7bd8
  Author: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
  tracing/events: fix the include file dependencies

Moved the TRACE_EVENT out of the ifdef protection of tracepoints.h
but uses the define of TRACE_EVENT itself as protection. This patch
adds comments to explain why.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing/events: fix the include file dependencies
Xiao Guangrong [Tue, 25 Aug 2009 06:06:22 +0000]
tracing/events: fix the include file dependencies

The TRACE_EVENT depends on the include/linux/tracepoint.h first
and include/trace/ftrace.h later, if we include the ftrace.h early,
a building error will occur.

Both define TRACE_EVENT in trace_a.h and trace_b.h, if we include
those in .c file, like this:

#define CREATE_TRACE_POINTS
include <trace/events/trace_a.h>
include <trace/events/trace_b.h>

The above will not work, because the TRACE_EVENT was re-defined by
the previous .h file.

Reported-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
LKML-Reference: <4A937F5E.3020802@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agoftrace: Move setting of clock-source out of options
Zhaolei [Tue, 25 Aug 2009 08:12:56 +0000]
ftrace: Move setting of clock-source out of options

There are many clock sources for the tracing system but we can only
enable/disable one at a time with the trace/options file.
We can move the setting of clock-source out of options and add a separate
file for it:
 # cat trace_clock
 [local] global
 # echo global > trace_clock
 # cat trace_clock
 local [global]

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A939D08.6050604@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing/filters: Support filtering for char * strings
Li Zefan [Fri, 7 Aug 2009 02:33:43 +0000]
tracing/filters: Support filtering for char * strings

Usually, char * entries are dangerous in traces because the string
can be released whereas a pointer to it can still wait to be read from
the ring buffer.

But sometimes we can assume it's safe, like in case of RO data
(eg: __file__ or __line__, used in bkl trace event). If these RO data
are in a module and so is the call to the trace event, then it's safe,
because the ring buffer will be flushed once this module get unloaded.

To allow char * to be treated as a string:

TRACE_EVENT(...,

TP_STRUCT__entry(
__field_ext(const char *, name, FILTER_PTR_STRING)
...
)

...
);

The filtering will not dereference "char *" unless the developer
explicitly sets FILTER_PTR_STR in __field_ext.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A7B9287.90205@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing/filters: Add __field_ext() to TRACE_EVENT
Li Zefan [Fri, 7 Aug 2009 02:33:22 +0000]
tracing/filters: Add __field_ext() to TRACE_EVENT

Add __field_ext(), so a field can be assigned to a specific
filter_type, which matches a corresponding filter function.

For example, a later patch will allow this:
__field_ext(const char *, str, FILTER_PTR_STR);

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A7B9272.6050709@cn.fujitsu.com>

[
  Fixed a -1 to FILTER_OTHER
  Forward ported to latest kernel.
]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing/filters: Add filter_type to struct ftrace_event_field
Li Zefan [Fri, 7 Aug 2009 02:33:02 +0000]
tracing/filters: Add filter_type to struct ftrace_event_field

The type of a field is stored as a string in @type, and here
we add @filter_type which is an enum value.

This prepares for later patches, so we can specifically assign
different @filter_type for the same @type.

For example normally a "char *" field is treated as a ptr,
but we may want it to be treated as a string when doing filting.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A7B925E.9030605@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing: Add vim script to enable folding for function_graph traces
Josh Triplett [Thu, 6 Aug 2009 14:57:01 +0000]
tracing: Add vim script to enable folding for function_graph traces

function_graph traces look like nested function calls, complete with
braces denoting the start and end of functions.  function-graph-fold.vim
teaches vim how to fold these functions, to make it more convenient to
browse them.

To use, :source function-graph-fold.vim while viewing a function_graph
trace, or use "view -S function-graph-fold.vim some-trace" to load it
from the command-line together with a trace.  You can then use the usual
vim fold commands, such as "za", to open and close nested functions.
While closed, a fold will show the total time taken for a call, as would
normally appear on the line with the closing brace.  Folded functions
will not include finish_task_switch(), so folding should remain
relatively sane even through a context switch.

Note that this will almost certainly only work well with a single-CPU
trace (e.g. trace-cmd report --cpu 1).  It also takes some time to run
(a few seconds for a large trace on my laptop).  Nevertheless, I found
it very handy to get an overview of a trace and then drill down on
problematic calls.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
LKML-Reference: <20090806145701.GB7661@feather>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 years agotracing/sched: show CPU task wakes up on in trace event
Steven Rostedt [Thu, 6 Aug 2009 18:59:32 +0000]
tracing/sched: show CPU task wakes up on in trace event

While debugging the scheduler push / pull algorithm, I found
it very annoying that the sched wake up events did not show
the CPU that the task was waking on. In order to analyze the
scheduler, I needed that information.

This patch adds recording of the CPU that a task is waking up
on.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

10 years agotracing: Create generic syscall TRACE_EVENTs
Josh Stone [Mon, 24 Aug 2009 21:43:14 +0000]
tracing: Create generic syscall TRACE_EVENTs

This converts the syscall_enter/exit tracepoints into TRACE_EVENTs, so
you can have generic ftrace events that capture all system calls with
arguments and return values.  These generic events are also renamed to
sys_enter/exit, so they're more closely aligned to the specific
sys_enter_foo events.

Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <1251150194-1713-5-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Move tracepoint callbacks from declaration to definition
Josh Stone [Mon, 24 Aug 2009 21:43:13 +0000]
tracing: Move tracepoint callbacks from declaration to definition

It's not strictly correct for the tracepoint reg/unreg callbacks to
occur when a client is hooking up, because the actual tracepoint may not
be present yet.  This happens to be fine for syscall, since that's in
the core kernel, but it would cause problems for tracepoints defined in
a module that hasn't been loaded yet.  It also means the reg/unreg has
to be EXPORTed for any modules to use the tracepoint (as in SystemTap).

This patch removes DECLARE_TRACE_WITH_CALLBACK, and instead introduces
DEFINE_TRACE_FN which stores the callbacks in struct tracepoint.  The
callbacks are used now when the active state of the tracepoint changes
in set_tracepoint & disable_tracepoint.

This also introduces TRACE_EVENT_FN, so ftrace events can also provide
registration callbacks if needed.

Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <1251150194-1713-4-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Make syscall tracepoints conditional
Josh Stone [Mon, 24 Aug 2009 21:43:12 +0000]
tracing: Make syscall tracepoints conditional

The syscall enter/exit tracepoints are only supported on archs that
HAVE_SYSCALL_TRACEPOINTS, so the declarations should be #ifdef'ed.
Also, the definition of syscall_regfunc and syscall_unregfunc should
depend on this same config, rather than the ftrace-specific one.

Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1251150194-1713-3-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Rename FTRACE_SYSCALLS for tracepoints
Josh Stone [Mon, 24 Aug 2009 21:43:11 +0000]
tracing: Rename FTRACE_SYSCALLS for tracepoints

s/HAVE_FTRACE_SYSCALLS/HAVE_SYSCALL_TRACEPOINTS/g
s/TIF_SYSCALL_FTRACE/TIF_SYSCALL_TRACEPOINT/g

The syscall enter/exit tracing is no longer specific to just ftrace, so
they now have names that reflect their tie to tracepoints instead.

Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <1251150194-1713-2-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Eliminate code duplication in kernel/tracepoint.c
Anirban Sinha [Tue, 25 Aug 2009 14:00:02 +0000]
tracing: Eliminate code duplication in kernel/tracepoint.c

Signed-off-by: Anirban Sinha <asinha@zeugmasystems.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: "Oleg Nesterov" <oleg@tv-sign.ru>
LKML-Reference: <DDFD17CC94A9BD49A82147DDF7D545C501EA9047@exchange.ZeugmaSystems.local>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/syscalls: Fix the output of syscalls with no arguments
Li Zefan [Thu, 20 Aug 2009 08:13:35 +0000]
tracing/syscalls: Fix the output of syscalls with no arguments

Before:

  # echo 1 > events/syscalls/sys_enter_sync/enable
  # cat events/syscalls/sys_enter_sync/format
  ...
        field:int nr;   offset:12;      size:4;

  print fmt: "# sync
  # cat trace
  ...
            sync-8950  [000]  2366.087670: sys_sync(

After:

  # echo 1 > events/syscalls/sys_enter_sync/enable
  # cat events/syscalls/sys_enter_sync/format
  ...
        field:int nr;   offset:12;      size:4;

  print fmt: ""
  # sync
  # cat trace
            sync-2134  [001]   136.780735: sys_sync()

Reported-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4A8D05AF.20103@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/syscalls: Add filtering support
Li Zefan [Wed, 19 Aug 2009 07:54:51 +0000]
tracing/syscalls: Add filtering support

Add filtering support for syscall events:

 # echo 'mode == 0666' > events/syscalls/sys_enter_open
 # echo 'ret == 0' > events/syscalls/sys_exit_open
 # echo 1 > events/syscalls/sys_enter_open
 # echo 1 > events/syscalls/sys_exit_open
 # cat trace
 ...
   modprobe-3084 [001] 117.463140: sys_open(filename: 917d3e8, flags: 0, mode: 1b6)
   modprobe-3084 [001] 117.463176: sys_open -> 0x0
       less-3086 [001] 117.510455: sys_open(filename: 9c6bdb8, flags: 8000, mode: 1b6)
   sendmail-2574 [001] 122.145840: sys_open(filename: b807a365, flags: 0, mode: 1b6)
 ...

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAFCB.1040006@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/events: Add trace_define_common_fields()
Li Zefan [Wed, 19 Aug 2009 07:54:32 +0000]
tracing/events: Add trace_define_common_fields()

Extract duplicate code. Also prepare for the later patch.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAFB8.1010304@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/events: Add ftrace_event_call param to define_fields()
Li Zefan [Wed, 19 Aug 2009 07:53:52 +0000]
tracing/events: Add ftrace_event_call param to define_fields()

This parameter is needed by syscall events to add define_fields()
handler.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAF90.6060801@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/syscalls: Add fields format for exit events
Li Zefan [Wed, 19 Aug 2009 07:53:05 +0000]
tracing/syscalls: Add fields format for exit events

Add "format" file for syscall exit events:

 # cat events/syscalls/sys_exit_open/format
 name: sys_exit_open
 ID: 344
 format:
         field:unsigned short common_type;       offset:0;       size:2;
         field:unsigned char common_flags;       offset:2;       size:1;
         field:unsigned char common_preempt_count;       offset:3;       size:1;
         field:int common_pid;   offset:4;       size:4;
         field:int common_tgid;  offset:8;       size:4;

         field:int nr;   offset:12;      size:4;
         field:unsigned long ret;        offset:16;      size:4;

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAF61.3060307@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/syscalls: Fix fields format for enter events
Li Zefan [Wed, 19 Aug 2009 07:52:25 +0000]
tracing/syscalls: Fix fields format for enter events

The "format" file of a trace event is originally for parsers to
parse ftrace binary output.

But the "format" file of a syscall event can only be used by
perfcounter, because it describes the format of struct
syscall_enter_record not struct syscall_trace_enter.

To fix this, we remove struct syscall_enter_record, and then
struct syscall_trace_enter will be used by both perf profile
and ftrace.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAF39.1030404@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years ago[S390] ftrace: update system call tracer support
Ingo Molnar [Tue, 18 Aug 2009 08:41:57 +0000]
[S390] ftrace: update system call tracer support

Commit fb34a08c3 ("tracing: Add trace events for each syscall
entry/exit") changed the lowlevel API to ftrace syscall tracing
but did not update s390 which started making use of it recently.

This broke the s390 build, as reported by Paul Mundt.

Update the callbacks with the syscall number and the syscall
return code values. This allows per syscall tracepoints,
syscall argument enumeration /debug/tracing/events/syscalls/
and perfcounters support and integration on s390 too.

Reported-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <tip-fb34a08c3469b2be9eae626ccb96476b4687b810@git.kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agoftrace: Simplify seqfile code
Li Zefan [Mon, 17 Aug 2009 08:54:03 +0000]
ftrace: Simplify seqfile code

Use seq_release_private().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A891AAB.8090701@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotrace_stack: Simplify seqfile code
Li Zefan [Mon, 17 Aug 2009 08:53:37 +0000]
trace_stack: Simplify seqfile code

Extract duplicate code in t_start() and t_next().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A891A91.4030602@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotrace_stat: Fix missing entry in stat file
Li Zefan [Mon, 17 Aug 2009 08:52:53 +0000]
trace_stat: Fix missing entry in stat file

One entry is missing in the output of a stat file.

The cause is, when stat_seq_start() is called the 2nd time, we
should start from the (pos-1)th elem in the rbtree but not pos,
because pos == 0 is the header.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A891A65.70009@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/syscalls: Fix to print parameter types
Li Zefan [Mon, 17 Aug 2009 08:55:18 +0000]
tracing/syscalls: Fix to print parameter types

When syscall tracing was implemented as a tracer,
"syscall_arg_type" trace option could be set to enable the
display of syscall parameter types.

Now this option is gone since it's no longer a tracer, but the
code is still there but dead.

So we remove dead code and re-enable the printing of paramete
types via the verbose option:

  # echo verbose > trace_options
  # echo syscalls > set_event
  # cat trace
...
        bash-3331  [000]    95.348937: sys_fcntl64 -> 0x1
        bash-3331  [000]    95.348942: sys_close(unsigned int fd: a)
...

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <4A891AF6.5050102@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing/events: Add module tracepoints
Li Zefan [Mon, 17 Aug 2009 08:56:28 +0000]
tracing/events: Add module tracepoints

Add trace points to trace module_load, module_free, module_get,
module_put and module_request, and use trace_event facility to
get the trace output.

Here's the sample output:

     TASK-PID    CPU#    TIMESTAMP  FUNCTION
        | |       |          |         |
    <...>-42    [000]     1.758380: module_request: fb0 wait=1 call_site=fb_open
    ...
    <...>-60    [000]     3.269403: module_load: scsi_wait_scan
    <...>-60    [000]     3.269432: module_put: scsi_wait_scan call_site=sys_init_module refcnt=0
    <...>-61    [001]     3.273168: module_free: scsi_wait_scan
    ...
    <...>-1021  [000]    13.836081: module_load: sunrpc
    <...>-1021  [000]    13.840589: module_put: sunrpc call_site=sys_init_module refcnt=-1
    <...>-1027  [000]    13.848098: module_get: sunrpc call_site=try_module_get refcnt=0
    <...>-1027  [000]    13.848308: module_get: sunrpc call_site=get_filesystem refcnt=1
    <...>-1027  [000]    13.848692: module_put: sunrpc call_site=put_filesystem refcnt=0
    ...
 modprobe-2587  [001]  1088.437213: module_load: trace_events_sample F
 modprobe-2587  [001]  1088.437786: module_put: trace_events_sample call_site=sys_init_module refcnt=0

Note:

- the taints flag can be 'F', 'C' and/or 'P' if mod->taints != 0

- the module refcnt is percpu, so it can be negative in a
  specific cpu

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <4A891B3C.5030608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing: Fix syscall tracing on !HAVE_FTRACE_SYSCALLS architectures
Ingo Molnar [Thu, 13 Aug 2009 21:37:26 +0000]
tracing: Fix syscall tracing on !HAVE_FTRACE_SYSCALLS architectures

The new syscall_regfunc()/unregfunc() functions rely on
the existence of TIF_SYSCALL_FTRACE - but that TIF flag
is only offered by HAVE_FTRACE_SYSCALLS.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agotracing: Support for syscall events raw records in perfcounters
Frederic Weisbecker [Tue, 11 Aug 2009 18:22:53 +0000]
tracing: Support for syscall events raw records in perfcounters

This bring the support for raw syscall events in perfcounters.
The arguments or exit value are saved as a raw sample using
the PERF_SAMPLE_RAW attribute in a perf counter.

Example (for now you must explicitly set the PERF_SAMPLE_RAW flag
in perf record):

perf record -e syscalls:sys_enter_open -f -F 1 -a
perf report -D

0x2cbb8 [0x50]: event: 9
.
. ... raw event: size 80 bytes
.  0000:  09 00 00 00 02 00 50 00 20 e9 39 ab 0a 7f 00 00  ......P. .9....
.  0010:  bc 14 00 00 bc 14 00 00 01 00 00 00 00 00 00 00  ...............
.  0020:  2c 00 00 00 15 01 01 00 bc 14 00 00 bc 14 00 00  ,..............
                  ^  ^  ^  ^  ^  ^  ^  ..........................
                  Event Size  struct trace_entry

.  0030:  00 00 00 00 46 98 43 02 00 00 00 00 80 08 00 00  ....F.C........
                  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^
                  ptr to file name        open flags

.  0040:  00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00  ...............
                  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^  ^
.         open mode               padding

0x2cbb8 [0x50]: PERF_EVENT_SAMPLE (IP, 2): 5308: 0x7f0aab39e920 period: 1

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>

10 years agotracing: Add fields format definition for syscall events
Frederic Weisbecker [Tue, 11 Aug 2009 17:03:54 +0000]
tracing: Add fields format definition for syscall events

Define the format of the syscall trace fields to parse the binary
values from a raw trace using the syscall events "format" file.

This is defined dynamically using the syscalls metadata.
It prepares the export of syscall event raw records to perf
counters.

Example:

$ cat /debug/tracing/events/syscalls/sys_enter_sched_getparam/format
name: sys_enter_sched_getparam
ID: 39
format:
field:unsigned short common_type; offset:0; size:2;
field:unsigned char common_flags; offset:2; size:1;
field:unsigned char common_preempt_count; offset:3; size:1;
field:int common_pid; offset:4; size:4;
field:int common_tgid; offset:8; size:4;

field:pid_t pid; offset:12; size:8;
field:struct sched_param * param; offset:20; size:8;

print fmt: "pid: 0x%08lx, param: 0x%08lx", ((unsigned long)(REC->pid)), ((unsigned long)(REC->param))

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>

10 years agotracing: Add ftrace event call parameter to its field descriptor handler
Frederic Weisbecker [Tue, 11 Aug 2009 15:42:52 +0000]
tracing: Add ftrace event call parameter to its field descriptor handler

Add the struct ftrace_event_call as a parameter of its show_format()
callback. This way we can use it from the syscall trace events to
retrieve the syscall name from the ftrace event call parameter and
describe its fields using the syscalls metadata.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>

10 years agotracing: Convert x86_64 mmap and uname to use DEFINE_SYSCALL
Jason Baron [Mon, 10 Aug 2009 20:53:11 +0000]
tracing: Convert x86_64 mmap and uname to use DEFINE_SYSCALL

A number of syscalls are not using 'DEFINE_SYSCALL'. I'm not sure why.
Convert x86_64 uname and mmap to use DEFINE_SYSCALL.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add more namespace area to 'perf list' output
Jason Baron [Mon, 10 Aug 2009 20:53:06 +0000]
tracing: Add more namespace area to 'perf list' output

The new syscall tracepoints names can be too long for the 'perf list'
output.
Add a few more characters.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add perf counter support for syscalls tracing
Jason Baron [Mon, 10 Aug 2009 20:53:02 +0000]
tracing: Add perf counter support for syscalls tracing

The perf counter support is automated for usual trace events. But we
have to define specific callbacks for this to handle syscalls trace
events

Make 'perf stat -e syscalls:sys_enter_blah' work with syscall style
tracepoints.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add individual syscalls tracepoint id support
Jason Baron [Mon, 10 Aug 2009 20:52:53 +0000]
tracing: Add individual syscalls tracepoint id support

The current state of syscalls tracepoints generates only one event id
for every syscall events.

This patch associates an id with each syscall trace event, so that we
can identify each syscall trace event using the 'perf' tool.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add trace events for each syscall entry/exit
Jason Baron [Mon, 10 Aug 2009 20:52:47 +0000]
tracing: Add trace events for each syscall entry/exit

Layer Frederic's syscall tracer on tracepoints. We create trace events
via hooking into the SYSCALL_DEFINE macros. This allows us to
individually toggle syscall entry and exit points on/off.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add ftrace_event_call void * 'data' field
Jason Baron [Mon, 10 Aug 2009 20:52:44 +0000]
tracing: Add ftrace_event_call void * 'data' field

add an optional void * pointer to 'ftrace_event_call' that is
passed in for regfunc and unregfunc.

This prepares for syscall tracepoints creation by passing the name of
the syscall we want to trace and then retrieve its number through our
arch syscall table.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Raw_init() bailout in trace event register fail case
Jason Baron [Mon, 10 Aug 2009 20:52:39 +0000]
tracing: Raw_init() bailout in trace event register fail case

Allow the return value of raw_init() trace event callback to bail us out
of creating a trace event file, in case we fail to register our
event.

Also, we plan to return -ENOSYS for syscall events that don't match any
syscalls listed in our arch tracing syscall table, we don't want to warn
in that case, we just want this event to be invisible in debugfs and
ignored.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Update FTRACE_SYSCALL_MAX
Jason Baron [Mon, 10 Aug 2009 20:52:35 +0000]
tracing: Update FTRACE_SYSCALL_MAX

update FTRACE_SYSCALL_MAX to the current number of syscalls

FTRACE_SYSCALL_MAX is a temporary solution to get the number of
syscalls supported by the arch until we find a more dynamic way
to get this number.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add syscall tracepoints
Jason Baron [Mon, 10 Aug 2009 20:52:31 +0000]
tracing: Add syscall tracepoints

add two tracepoints in syscall exit and entry path, conditioned on
TIF_SYSCALL_FTRACE. Supports the syscall trace event code.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Add DECLARE_TRACE_WITH_CALLBACK() macro
Jason Baron [Mon, 10 Aug 2009 20:52:27 +0000]
tracing: Add DECLARE_TRACE_WITH_CALLBACK() macro

Introduce a new 'DECLARE_TRACE_WITH_CALLBACK()' macro, so that
tracepoints can associate an external register/unregister function.

This prepares for the syscalls tracer conversion to trace events. We
will need to perform arch level operations once a syscall event is
turned on/off, such as TIF flags setting, hence the need of such
specific callbacks.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Call arch_init_ftrace_syscalls at boot
Jason Baron [Mon, 10 Aug 2009 20:52:23 +0000]
tracing: Call arch_init_ftrace_syscalls at boot

Call arch_init_ftrace_syscalls at boot, so we can determine early the
set of syscalls for the syscall trace events.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Map syscall name to number
Jason Baron [Mon, 10 Aug 2009 20:52:13 +0000]
tracing: Map syscall name to number

Add a new function to support translating a syscall name to number at
runtime.
This allows the syscall event tracer to map syscall names to number.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agotracing: Rename set_tracer_flags()'s local variable trace_flags
Zhaolei [Fri, 7 Aug 2009 10:53:21 +0000]
tracing: Rename set_tracer_flags()'s local variable trace_flags

set_tracer_flags() have a local variable named trace_flags which has
the same name than a global one in the same scope.
This leads to confusion, using tracer_flags should be better by its
meaning.

Changelog:
v1->v2: Simplified another patch in this patchset, no change in this
        patch.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

10 years agoMerge branch 'linus' into tracing/core
Ingo Molnar [Tue, 11 Aug 2009 12:19:09 +0000]
Merge branch 'linus' into tracing/core

Conflicts:
kernel/trace/trace_events_filter.c

We use the tracing/core version.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agopty: fix data loss when stopped (^S/^Q)
Linus Torvalds [Mon, 10 Aug 2009 20:21:19 +0000]
pty: fix data loss when stopped (^S/^Q)

Commit d945cb9cc ("pty: Rework the pty layer to use the normal buffering
logic") dropped the test for 'tty->stopped' in pty_write_room(), which
then causes the n_tty line discipline thing to not throttle the data
properly when the tty is stopped.

So instead of pausing the write due to the tty being stopped, the ldisc
layer would go ahead and push it down to the pty.  The pty write()
routine would then refuse to take the data (because it _did_ check
'stopped'), and the data wouldn't actually be written.

This whole stopped test should eventually be moved into the tty ldisc
layer rather than have low-level tty drivers care about these things,
but right now the fix is to just re-instate the missing pty 'stopped'
handling.

Reported-and-tested-by: Artur Skawina <art.08.09@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

10 years agoMerge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux...
Linus Torvalds [Mon, 10 Aug 2009 18:48:51 +0000]
Merge branch 'perfcounters-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits)
  perf_counter: Zero dead bytes from ftrace raw samples size alignment
  perf_counter: Subtract the buffer size field from the event record size
  perf_counter: Require CAP_SYS_ADMIN for raw tracepoint data
  perf_counter: Correct PERF_SAMPLE_RAW output
  perf tools: callchain: Fix bad rounding of minimum rate
  perf_counter tools: Fix libbfd detection for systems with libz dependency
  perf: "Longum est iter per praecepta, breve et efficax per exempla"
  perf_counter: Fix a race on perf_counter_ctx
  perf_counter: Fix tracepoint sampling to be part of generic sampling
  perf_counter: Work around gcc warning by initializing tracepoint record unconditionally
  perf tools: callchain: Fix sum of percentages to be 100% by displaying amount of ignored chains in fractal mode
  perf tools: callchain: Fix 'perf report' display to be callchain by default
  perf tools: callchain: Fix spurious 'perf report' warnings: ignore empty callchains
  perf record: Fix the -A UI for empty or non-existent perf.data
  perf util: Fix do_read() to fail on EOF instead of busy-looping
  perf list: Fix the output to not include tracepoints without an id
  perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support
  perf stat: Fix tool option consistency: rename -S/--scale to -c/--scale
  perf report: Add debug help for the finding of symbol bugs - show the symtab origin (DSO, build-id, kernel, etc)
  perf report: Fix per task mult-counter stat reporting
  ...

10 years agoMerge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
Linus Torvalds [Mon, 10 Aug 2009 18:21:13 +0000]
Merge branch 'irq-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86/irq: Fix move_irq_desc() for nodes without ram

10 years agoMerge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
Linus Torvalds [Mon, 10 Aug 2009 18:11:40 +0000]
Merge branch 'x86-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix serialization in pit_expect_msb()

10 years agoMerge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes...
Linus Torvalds [Mon, 10 Aug 2009 18:00:37 +0000]
Merge branch 'for-linus' of git://git./linux/kernel/git/jbarnes/pci-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  PCI hotplug: SGI hotplug: do not use hotplug_slot_attr
  PCI hotplug: SGI hotplug: fix build failure

10 years agox86: Fix serialization in pit_expect_msb()
Linus Torvalds [Fri, 31 Jul 2009 19:45:41 +0000]
x86: Fix serialization in pit_expect_msb()

Wei Chong Tan reported a fast-PIT-calibration corner-case:

| pit_expect_msb() is vulnerable to SMI disturbance corner case
| in some platforms which causes /proc/cpuinfo to show wrong
| CPU MHz value when quick_pit_calibrate() jumps to success
| section.

I think that the real issue isn't even an SMI - but the fact
that in the very last iteration of the loop, there's no
serializing instruction _after_ the last 'rdtsc'. So even in
the absense of SMI's, we do have a situation where the cycle
counter was read without proper serialization.

The last check should be done outside the outer loop, since
_inside_ the outer loop, we'll be testing that the PIT has
the right MSB value has the right value in the next iteration.

So only the _last_ iteration is special, because that's the one
that will not check the PIT MSB value any more, and because the
final 'get_cycles()' isn't serialized.

In other words:

 - I'd like to move the PIT MSB check to after the last
   iteration, rather than in every iteration

 - I think we should comment on the fact that it's also a
   serializing instruction and so 'fences in' the TSC read.

Here's a suggested replacement.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: "Tan, Wei Chong" <wei.chong.tan@intel.com>
Tested-by: "Tan, Wei Chong" <wei.chong.tan@intel.com>
LKML-Reference: <B28277FD4E0F9247A3D55704C440A140D5D683F3@pgsmsx504.gar.corp.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agoMerge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
Linus Torvalds [Mon, 10 Aug 2009 16:00:47 +0000]
Merge branch 'for-linus' of git://git./linux/kernel/git/jmorris/security-testing-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  mm_for_maps: take ->cred_guard_mutex to fix the race with exec
  mm_for_maps: shift down_read(mmap_sem) to the caller
  mm_for_maps: simplify, use ptrace_may_access()

10 years agoMerge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Linus Torvalds [Mon, 10 Aug 2009 15:59:56 +0000]
Merge branch 'merge' of git://git./linux/kernel/git/benh/powerpc

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/dma: pci_set_dma_mask() shouldn't fail if mask fits in RAM

10 years agoMN10300: includecheck fix: mn10300, pci.h
Jaswinder Singh Rajput [Mon, 10 Aug 2009 15:45:42 +0000]
MN10300: includecheck fix: mn10300, pci.h

Fix the following 'make includecheck' warning:

  arch/mn10300/include/asm/pci.h: linux/mm.h is included more than once.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

10 years agomempool.c: clean up type-casting
Figo.zhang [Sat, 8 Aug 2009 13:01:22 +0000]
mempool.c: clean up type-casting

clean up type-casting twice.  "size_t" is typedef as "unsigned long" in
64-bit system, and "unsigned int" in 32-bit system, and the intermediate
cast to 'long' is pointless.

Signed-off-by: Figo.zhang <figo1802@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

10 years agodocumentation: register ioctl entry of nilfs2
Ryusuke Konishi [Sat, 8 Aug 2009 08:52:50 +0000]
documentation: register ioctl entry of nilfs2

This will register the ioctl range used by nilfs2 file system to the
table listed in Documentation/ioctl/ioctl-number.txt.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

10 years agoperf_counter: Zero dead bytes from ftrace raw samples size alignment
Frederic Weisbecker [Mon, 10 Aug 2009 14:38:36 +0000]
perf_counter: Zero dead bytes from ftrace raw samples size alignment

After aligning the ftrace raw samples, there are dead bytes storing
random data from the stack. We don't want to leak these to userspace,
then zero these out.

Before:

0x2de88 [0x50]: event: 9
.
. ... raw event: size 80 bytes
.  0000:  09 00 00 00 01 00 50 00 d0 c7 00 81 ff ff ff ff  ......P........
.  0010:  68 01 00 00 68 01 00 00 2c 00 00 00 00 00 00 00  h...h...,......
.  0020:  2c 00 00 00 2b 00 01 02 68 01 00 00 68 01 00 00  ,...+...h...h..
.  0030:  6b 6f 6e 64 65 6d 61 6e 64 2f 30 00 00 00 00 00  kondemand/0....
.  0040:  68 01 00 00 40 7f 46 81 ff ff ff ff 00 10 1b 7f  h...@.F........
                                                      ^  ^  ^  ^
                                                         Leak

After:

0x2d318 [0x50]: event: 9
.
. ... raw event: size 80 bytes
.  0000:  09 00 00 00 01 00 50 00 d0 c7 00 81 ff ff ff ff  ......P........
.  0010:  68 01 00 00 68 01 00 00 68 14 00 00 00 00 00 00  h...h...h......
.  0020:  2c 00 00 00 2b 00 01 02 68 01 00 00 68 01 00 00  ,...+...h...h..
.  0030:  6b 6f 6e 64 65 6d 61 6e 64 2f 30 00 00 00 00 00  kondemand/0....
.  0040:  68 01 00 00 a0 80 46 81 ff ff ff ff 00 00 00 00  h.....F........
                                                      ^  ^  ^  ^
 Fixed

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1249915116-5210-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>

10 years agoperf_counter: Subtract the buffer size field from the event record size
Frederic Weisbecker [Mon, 10 Aug 2009 14:11:32 +0000]
perf_counter: Subtract the buffer size field from the event record size

We compute the perf raw sample size by aligning the raw ftrace
event size plus the buffer size field itself. We do that
instead of aligning only the perf raw sample size, so that we
might economize some in some cases.

But this buffer size field is not stored in the perf raw
sample, we must then substract its size from the buffer once we
computed the alignment unless we may get a useless u32 field in
the buffer.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20090810141129.GA5124@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agomm_for_maps: take ->cred_guard_mutex to fix the race with exec
Oleg Nesterov [Fri, 10 Jul 2009 01:27:40 +0000]
mm_for_maps: take ->cred_guard_mutex to fix the race with exec

The problem is minor, but without ->cred_guard_mutex held we can race
with exec() and get the new ->mm but check old creds.

Now we do not need to re-check task->mm after ptrace_may_access(), it
can't be changed to the new mm under us.

Strictly speaking, this also fixes another very minor problem. Unless
security check fails or the task exits mm_for_maps() should never
return NULL, the caller should get either old or new ->mm.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

10 years agomm_for_maps: shift down_read(mmap_sem) to the caller
Oleg Nesterov [Fri, 10 Jul 2009 01:27:38 +0000]
mm_for_maps: shift down_read(mmap_sem) to the caller

mm_for_maps() takes ->mmap_sem after security checks, this looks
strange and obfuscates the locking rules. Move this lock to its
single caller, m_start().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

10 years agomm_for_maps: simplify, use ptrace_may_access()
Oleg Nesterov [Tue, 23 Jun 2009 19:25:32 +0000]
mm_for_maps: simplify, use ptrace_may_access()

It would be nice to kill __ptrace_may_access(). It requires task_lock(),
but this lock is only needed to read mm->flags in the middle.

Convert mm_for_maps() to use ptrace_may_access(), this also simplifies
the code a little bit.

Also, we do not need to take ->mmap_sem in advance. In fact I think
mm_for_maps() should not play with ->mmap_sem at all, the caller should
take this lock.

With or without this patch, without ->cred_guard_mutex held we can race
with exec() and get the new ->mm but check old creds.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

10 years agoperf_counter: Require CAP_SYS_ADMIN for raw tracepoint data
Peter Zijlstra [Mon, 10 Aug 2009 09:20:12 +0000]
perf_counter: Require CAP_SYS_ADMIN for raw tracepoint data

Raw tracepoint data contains various kernel internals and
data from other users, so restrict this to CAP_SYS_ADMIN.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1249896452.17467.75.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agoperf_counter: Correct PERF_SAMPLE_RAW output
Peter Zijlstra [Mon, 10 Aug 2009 09:16:52 +0000]
perf_counter: Correct PERF_SAMPLE_RAW output

PERF_SAMPLE_* output switches should unconditionally output the
correct format, as they are the only way to unambiguously parse
the PERF_EVENT_SAMPLE data.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1249896447.17467.74.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agopowerpc/dma: pci_set_dma_mask() shouldn't fail if mask fits in RAM
Benjamin Herrenschmidt [Mon, 10 Aug 2009 06:36:38 +0000]
powerpc/dma: pci_set_dma_mask() shouldn't fail if mask fits in RAM

On an iMac G5, the b43 driver is failing to initialise because trying to
set the dma mask to 30-bit fails. Even though there's only 512MiB of RAM
in the machine anyway:
https://bugzilla.redhat.com/show_bug.cgi?id=514787

We should probably let it succeed if the available RAM in the system
doesn't exceed the requested limit.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

10 years agoMerge branch 'for-linus' of git://git.infradead.org/ubi-2.6
Linus Torvalds [Sun, 9 Aug 2009 21:58:34 +0000]
Merge branch 'for-linus' of git://git.infradead.org/ubi-2.6

* 'for-linus' of git://git.infradead.org/ubi-2.6:
  UBI: compatible fallback in absense of sequence numbers
  UBI: fix double free on error path

10 years agoMerge branch 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Linus Torvalds [Sun, 9 Aug 2009 21:58:21 +0000]
Merge branch 'kvm-updates/2.6.31' of git://git./virt/kvm/kvm

* 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: Avoid redelivery of edge interrupt before next edge
  KVM: MMU: limit rmap chain length
  KVM: ia64: fix build failures due to ia64/unsigned long mismatches
  KVM: Make KVM_HPAGES_PER_HPAGE unsigned long to avoid build error on powerpc
  KVM: fix ack not being delivered when msi present
  KVM: s390: fix wait_queue handling
  KVM: VMX: Fix locking imbalance on emulation failure
  KVM: VMX: Fix locking order in handle_invalid_guest_state
  KVM: MMU: handle n_free_mmu_pages > n_alloc_mmu_pages in kvm_mmu_change_mmu_pages
  KVM: SVM: force new asid on vcpu migration
  KVM: x86: verify MTRR/PAT validity
  KVM: PIT: fix kpit_elapsed division by zero
  KVM: Fix KVM_GET_MSR_INDEX_LIST

10 years agoMerge branch 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
Linus Torvalds [Sun, 9 Aug 2009 21:58:09 +0000]
Merge branch 'drm-fixes' of git://git./linux/kernel/git/airlied/drm-2.6

* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
  drm/i915: silence vblank warnings
  drm: silence pointless vblank warning.
  drm: When adding probed modes, preserve duplicate mode types

10 years agoMerge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 9 Aug 2009 21:57:41 +0000]
Merge branch 'timers-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  posix_cpu_timers_exit_group(): Do not use thread_group_cputimer()

10 years agoMerge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 9 Aug 2009 21:57:26 +0000]
Merge branch 'tracing-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf_counter: Fix/complete ftrace event records sampling
  perf_counter, ftrace: Fix perf_counter integration
  tracing/filters: Always free pred on filter_add_subsystem_pred() failure
  tracing/filters: Don't use pred on alloc failure
  ring-buffer: Fix memleak in ring_buffer_free()
  tracing: Fix recordmcount.pl to handle sections with only weak functions
  ring-buffer: Fix advance of reader in rb_buffer_peek()
  tracing: do not use functions starting with .L in recordmcount.pl
  ring-buffer: do not disable ring buffer on oops_in_progress
  ring-buffer: fix check of try_to_discard result

10 years agoMerge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
Linus Torvalds [Sun, 9 Aug 2009 21:57:09 +0000]
Merge branch 'x86-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: fix buffer overflow in efi_init()
  x86: Add quirk to make Apple MacBookPro5,1 use reboot=pci
  x86: Fix MSI-X initialization by using online_mask for x2apic target_cpus
  x86: Fix VMI && stack protector

10 years agoMerge branch 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 9 Aug 2009 21:56:51 +0000]
Merge branch 'core-fixes-for-linus-2' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  lockdep: Fix typos in documentation
  lockdep: Fix file mode of lock_stat
  rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()

10 years agoperf tools: callchain: Fix bad rounding of minimum rate
Frederic Weisbecker [Sun, 9 Aug 2009 02:19:15 +0000]
perf tools: callchain: Fix bad rounding of minimum rate

Sometimes we get callchain branches that have a rate under the
limit given by the user.

Say you launched:

 perf record -f -g -a ./hackbench 10
 perf report -g fractal,10.0

And you got:

2.33%       hackbench  [kernel]                  [k] _spin_lock_irqsave
                |
                |--78.57%-- remove_wait_queue
                |          poll_freewait
                |          do_sys_poll
                |          sys_poll
                |          sysenter_dispatch
                |          0xf7ffa430
                |          0x1ffadea3c
                |
                |--7.14%-- __up_read
                |          up_read
                |          do_page_fault
                |          page_fault
                |          0xf7ffa430
                |          0xa0df710000000a
                ...

It is abnormal to get a 7.14% branch whereas we passed a 10%
filter.

The problem is that we round down the minimum threshold. This
happens mostly when we have very low number of events. If the
total amount of your branch is 4 and you have a subranch of 3
events, filtering to 90% will be computed like follows:

  limit = 4 * 0.9;

The result is about 3.6, but the cast to integer will round
down to 3. It means that our filter is actually of 75%

We must then explicitly round up the minimum threshold.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: acme@redhat.com
Cc: peterz@infradead.org
Cc: efault@gmx.de
LKML-Reference: <20090809024235.GA10146@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agoperf_counter tools: Fix libbfd detection for systems with libz dependency
Mike Galbraith [Sat, 8 Aug 2009 12:14:15 +0000]
perf_counter tools: Fix libbfd detection for systems with libz dependency

Due to a libz dependency in some distro's binutils package,
C++ demangle support isn't compiled in despite the necessary
libraries being available.

Fix this by adding a -lz link test to the dependency detection
rules.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1249733655.6929.5.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agoperf: "Longum est iter per praecepta, breve et efficax per exempla"
Carlos R. Mafra [Wed, 5 Aug 2009 18:53:34 +0000]
perf: "Longum est iter per praecepta, breve et efficax per exempla"

A few examples of how 'perf' can be used, from an e-mail by
Ingo Molnar http://lkml.org/lkml/2009/8/4/346.

Signed-off-by: Carlos R. Mafra <crmafra2@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Valdis.Kletnieks@vt.edu
LKML-Reference: <20090805185334.GA4535@Pilar.aei.mpg.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 years agoperf_counter: Fix a race on perf_counter_ctx
Peter Zijlstra [Fri, 7 Aug 2009 17:49:01 +0000]
perf_counter: Fix a race on perf_counter_ctx

While extending perfcounters with BTS hw-tracing, Markus
Metzger managed to trigger this warning:

   [  995.557128] WARNING: at kernel/perf_counter.c:1191 __perf_counter_task_sched_out+0x48/0x6b()

triggers because commit
9f498cc5be7e013d8d6e4c616980ed0ffc8680d2 (perf_counter: Full
task tracing) removed clearing of tsk->perf_counter_ctxp out
from under ctx->lock which introduced a race (against
perf_lock_task_context).

Move it back and deal with the exit notification by explicitly
passing along the former task context.

Reported-by: Markus T Metzger <markus.t.metzger@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1249667341.17467.5.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>