[PATCH] kprobes: fix race in recovery of reentrant probe

[linux-2.6-omap-h63xx.git] / arch / powerpc / kernel / kprobes.c

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 27b0c40601fb5d6db8a13b9915ad2d626152173f..cfab48566db1306c3e8f47b5034ca703a67f471b 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -179,6 +179,18 @@ static inline int kprobe_handler(struct pt_regs *regs)
                        kcb->kprobe_status = KPROBE_REENTER;
                        return 1;
                } else {
+                       if (*addr != BREAKPOINT_INSTRUCTION) {
+                               /* If trap variant, then it belongs not to us */
+                               kprobe_opcode_t cur_insn = *addr;
+                               if (is_trap(cur_insn))
+                                       goto no_kprobe;
+                               /* The breakpoint instruction was removed by
+                                * another cpu right after we hit, no further
+                                * handling of this interrupt is appropriate
+                                */
+                               ret = 1;
+                               goto no_kprobe;
+                       }
                        p = __get_cpu_var(current_kprobe);
                        if (p->break_handler && p->break_handler(p, regs)) {
                                goto ss_probe;