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authorGerald Britton <gbritton@alum.mit.edu>2006-02-14 10:19:04 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-14 08:25:29 -0800
commit303794400992b907b7cac0d91788603636c7e0fe (patch)
tree012781f808f48d80b32e435a4f27b6e8524d0ff0 /arch
parentb739db79a434aec89027a109d85de305e6bdeb93 (diff)
downloadlinux-2.6.34-ux500-303794400992b907b7cac0d91788603636c7e0fe.tar.gz
[PATCH] x86: fix oprofile kernel callgraph regression
Fix x86 oprofile regression introduced by: commit c34d1b4d165c67b966bca4aba026443d7ff161eb [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>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/oprofile/backtrace.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/i386/oprofile/backtrace.c b/arch/i386/oprofile/backtrace.c
index acc18138fb2..c049ce414f0 100644
--- a/arch/i386/oprofile/backtrace.c
+++ b/arch/i386/oprofile/backtrace.c
@@ -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);
}