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[PATCH 1/2] x86: fix kprobe_handler reenable preemption
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, Ingo Molnar <mingo at elte dot hu>
- Cc: Roland McGrath <roland at redhat dot com>, prasanna at in dot ibm dot com, anil dot s dot keshavamurthy at intel dot com, davem at davemloft dot net, Harvey Harrison <harvey dot harrison at gmail dot com>, systemtap-ml <systemtap at sources dot redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, Arjan van de Ven <arjan at infradead dot org>
- Date: Tue, 18 Dec 2007 18:18:50 -0500
- Subject: [PATCH 1/2] x86: fix kprobe_handler reenable preemption
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@redhat.com>
---
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@redhat.com, masami.hiramatsu.pt@hitachi.com