oProfile: oops when profile_pc() returns ~0LU
authorPhilippe Elie <phil.el@wanadoo.fr>
Thu, 15 Nov 2007 00:58:48 +0000 (16:58 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Thu, 15 Nov 2007 02:45:37 +0000 (18:45 -0800)
commitdf9d177aa28d50e64bae6fbd6b263833079e3571
treeb265158232a39d9d45cac0a97d5fdc17e7ca237d
parent03ad369ac900116f35da7505f768ebbd481d09a4
oProfile: oops when profile_pc() returns ~0LU

Instruction pointer returned by profile_pc() can be a random value.  This
break the assumption than we can safely set struct op_sample.eip field to a
magic value to signal to the per-cpu buffer reader side special event like
task switch ending up in a segfault in get_task_mm() when profile_pc()
return ~0UL.  Fixed by sanitizing the sampled eip and reject/log invalid
eip.

Problem reported by Sami Farin, patch tested by him.

Signed-off-by: Philippe Elie <phil.el@wanadoo.fr>
Tested-by: Sami Farin <safari-kernel@safari.iki.fi>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/oprofile/cpu_buffer.c
drivers/oprofile/cpu_buffer.h
drivers/oprofile/oprofile_stats.c