[PATCH] kprobes: fix bug when probed on task and isr functions
This patch fixes a race condition where in system used to hang or sometime
crash within minutes when kprobes are inserted on ISR routine and a task
routine.
The fix has been stress tested on i386, ia64, pp64 and on x86_64. To
reproduce the problem insert kprobes on schedule() and do_IRQ() functions
and you should see hang or system crash.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c
index 591e4b6..7e80d49 100644
--- a/arch/ppc64/kernel/kprobes.c
+++ b/arch/ppc64/kernel/kprobes.c
@@ -102,7 +102,7 @@
regs->msr |= MSR_SE;
/* single step inline if it is a trap variant */
- if (IS_TW(insn) || IS_TD(insn) || IS_TWI(insn) || IS_TDI(insn))
+ if (is_trap(insn))
regs->nip = (unsigned long)p->addr;
else
regs->nip = (unsigned long)p->ainsn.insn;
@@ -152,7 +152,9 @@
Disarm the probe we just hit, and ignore it. */
p = get_kprobe(addr);
if (p) {
- if (kprobe_status == KPROBE_HIT_SS) {
+ kprobe_opcode_t insn = *p->ainsn.insn;
+ if (kprobe_status == KPROBE_HIT_SS &&
+ is_trap(insn)) {
regs->msr &= ~MSR_SE;
regs->msr |= kprobe_saved_msr;
unlock_kprobes();
@@ -192,8 +194,7 @@
* trap variant, it could belong to someone else
*/
kprobe_opcode_t cur_insn = *addr;
- if (IS_TW(cur_insn) || IS_TD(cur_insn) ||
- IS_TWI(cur_insn) || IS_TDI(cur_insn))
+ if (is_trap(cur_insn))
goto no_kprobe;
/*
* The breakpoint instruction was removed right
@@ -403,7 +404,7 @@
default:
break;
}
- preempt_enable();
+ preempt_enable_no_resched();
return ret;
}
