]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
[PATCH] OProfile: fixed x86_64 incorrect kernel call graphs
authorTong Li <tong.n.li@intel.com>
Fri, 3 Feb 2006 11:04:09 +0000 (03:04 -0800)
committerLinus Torvalds <torvalds@g5.osdl.org>
Fri, 3 Feb 2006 16:32:04 +0000 (08:32 -0800)
commit23332c2e9da16b717f18fd95bc90211a663aa6ee
tree873e445688472fd1726c0e48113f63a585d03b39
parent8145916996b91d42b8bb4b0fcd508af295222c7c
[PATCH] OProfile: fixed x86_64 incorrect kernel call graphs

Fix the problem in kernel 2.6.15.1 (and early versions) that OProfile on
x86_64 does not correctly collect the stack traces for kernel functions.

The original code in valid_kernel_stack() in arch/i386/oprofile/backtrace.c
assumes that the frame pointer (headaddr) should be greater than stack
(i.e., regs).

This assumption is wrong for x86_64 because NMIs in x86_64 use a seperate
stack different from the kernel stack.  Therefore, the variable stack now
points to some location on the NMI stack, which turns out to be at a higher
address than the frame pointer (headaddr) on the kernel stack.  The correct
comparison here should be between headaddr and regs->rsp for x86_64.

Signed-off-by: Tong Li <tong.n.li@intel.com>
Cc: John Levon <levon@movementarian.org>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
arch/i386/oprofile/backtrace.c