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[PATCH] x86: fix oprofile kernel callgraph regression

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Fix x86 oprofile regression introduced by:
  commit c34d1b4d16
  [PATCH] mm: kill check_user_page_readable

That commit reorganized tests for the userspace stack walking moving all
those tests into dump_backtrace(), however, dump_backtrace() was used for
both userspace and kernel stalk walking.  The result is typically no
recorded callgraph information for kernel samples.

Revive the original function as dump_kernel_backtrace() and rename the
other to dump_user_backtrace() to avoid future confusion.

Signed-off-by: Gerald Britton <gbritton@alum.mit.edu>
Apology-from: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Gerald Britton 2006-02-14 10:19:04 -05:00 committed by Linus Torvalds
parent b739db79a4
commit 3037944009
1 changed files with 16 additions and 3 deletions
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19
arch/i386/oprofile/backtrace.c
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@ -20,7 +20,20 @@ struct frame_head {
} __attribute__((packed));
static struct frame_head *
dump_backtrace(struct frame_head * head)
dump_kernel_backtrace(struct frame_head * head)
{
oprofile_add_trace(head->ret);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
if (head >= head->ebp)
return NULL;
return head->ebp;
}
static struct frame_head *
dump_user_backtrace(struct frame_head * head)
{
struct frame_head bufhead[2];
@ -105,10 +118,10 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
if (!user_mode_vm(regs)) {
while (depth-- && valid_kernel_stack(head, regs))
head = dump_backtrace(head);
head = dump_kernel_backtrace(head);
return;
}
while (depth-- && head)
head = dump_backtrace(head);
head = dump_user_backtrace(head);
}