Thread (6 messages) flat view 6 messages, 2 authors, 2011-07-11
STALE5505d

[v2 PATCH 2/2] booke/kprobe: remove unnecessary preempt_enable_no_resched

From: Tiejun Chen <hidden>
Date: 2011-07-11 02:36:30
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Linus Torvalds

When enable CONFIG_PREEMPT we will trigger the following call trace:

BUG: scheduling while atomic: swapper/1/0x10000000
...

krpobe always goes through the following path:

program_check_exception()
        |
        + notify_die(DIE_BPT, "breakpoint",...)
                |
                + kprobe_handler()
                        |
                        + preempt_disable();
                        + break_handler() <- preempt_enable_no_resched()
                        + emulate_step()
                        + preempt_enable_no_resched()
                        ...
        exit

We should remove unnecessary preempt_enable_no_resched() inside of break_handler()
since looks longjmp_break_handler() always go the above path.

Signed-off-by: Tiejun Chen <redacted>
---
 arch/powerpc/kernel/kprobes.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index bc47352..a8a2a4d 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -552,7 +552,6 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 	 * saved regs...
 	 */
 	memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
-	preempt_enable_no_resched();
 	return 1;
 }
 
-- 
1.5.6
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