[PATCH 1/2] x86: fix kprobe_handler reenable preemption

From: Masami Hiramatsu
Date: Tue Dec 18 2007 - 18:19:41 EST


Fix a preemption bug in kprobe_handler(). It has to call preempt_enable()
before returning.
I think this is critical on preemptive kernel.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
arch/x86/kernel/kprobes.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

Index: b/arch/x86/kernel/kprobes.c
===================================================================
--- a/arch/x86/kernel/kprobes.c 2007-12-18 12:51:00.000000000 -0500
+++ b/arch/x86/kernel/kprobes.c 2007-12-18 12:53:38.000000000 -0500
@@ -467,7 +467,8 @@
arch_disarm_kprobe(p);
regs->ip = (unsigned long)p->addr;
reset_current_kprobe();
- return 1;
+ ret = 1;
+ goto no_kprobe;
#endif
}
/* We have reentered the kprobe_handler(), since
@@ -481,7 +482,7 @@
kprobes_inc_nmissed_count(p);
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_REENTER;
- return 1;
+ ret = 1;
} else {
if (*addr != BREAKPOINT_INSTRUCTION) {
/* The breakpoint instruction was removed by

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx, masami.hiramatsu.pt@xxxxxxxxxxx


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