tracing: Protect tracer flags with trace_types_lock
authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>
Thu, 14 Mar 2013 17:50:56 +0000 (13:50 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 5 Apr 2013 17:04:37 +0000 (10:04 -0700)
commit2f6b6e28ca9af9c1f745efa9277e3e7c9ad64883
tree2e66c696fe47845e4d2f3ed4cd12d02441ddf9b5
parent2457a4005a53bd8d9a266ab8f9f6388b57ca133a
tracing: Protect tracer flags with trace_types_lock

commit 69d34da2984c95b33ea21518227e1f9470f11d95 upstream.

Seems that the tracer flags have never been protected from
synchronous writes. Luckily, admins don't usually modify the
tracing flags via two different tasks. But if scripts were to
be used to modify them, then they could get corrupted.

Move the trace_types_lock that protects against tracers changing
to also protect the flags being set.

[Backported for 3.4, 3.0-stable. Moved return to after unlock.]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Reviewed-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/trace/trace.c