[GIT PULL] perf fix

From: Ingo Molnar
Date: Tue Apr 20 2010 - 03:33:25 EST


Linus,

Please pull the latest perf-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git perf-fixes-for-linus

Thanks,

Ingo

------------------>
Frederic Weisbecker (1):
perf: Fix unsafe frame rewinding with hot regs fetching


arch/x86/kernel/dumpstack.h | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.h b/arch/x86/kernel/dumpstack.h
index e39e771..e1a93be 100644
--- a/arch/x86/kernel/dumpstack.h
+++ b/arch/x86/kernel/dumpstack.h
@@ -14,6 +14,8 @@
#define get_bp(bp) asm("movq %%rbp, %0" : "=r" (bp) :)
#endif

+#include <linux/uaccess.h>
+
extern void
show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp, char *log_lvl);
@@ -42,8 +44,10 @@ static inline unsigned long rewind_frame_pointer(int n)
get_bp(frame);

#ifdef CONFIG_FRAME_POINTER
- while (n--)
- frame = frame->next_frame;
+ while (n--) {
+ if (probe_kernel_address(&frame->next_frame, frame))
+ break;
+ }
#endif

return (unsigned long)frame;
--
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