[PATCH] Kprobes/IA64: check jprobe break before handling

Once the jprobe instrumented function returns, it executes a jprobe_break
which is a break instruction with __IA64_JPROBE_BREAK value.  The current
patch checks for this break value, before assuming that jprobe instrumented
function just completed.

The previous code was not checking for this value and that was a bug.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 3 deletions

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 027d656664d2..41e80b42d3f3 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -419,10 +419,11 @@ static void prepare_ss(struct kprobe *p, struct pt_regs *regs)
         ia64_psr(regs)->ss = 1;
 }
 
-static int pre_kprobes_handler(struct pt_regs *regs)
+static int pre_kprobes_handler(struct die_args *args)
 {
         struct kprobe *p;
         int ret = 0;
+        struct pt_regs *regs = args->regs;
         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 
         preempt_disable();
@@ -437,7 +438,7 @@ static int pre_kprobes_handler(struct pt_regs *regs)
                         }
                         arch_disarm_kprobe(p);
                         ret = 1;
-                } else {
+                } else if (args->err == __IA64_BREAK_JPROBE) {
                         /*
                          * jprobe instrumented function just completed
                          */
@@ -445,6 +446,9 @@ static int pre_kprobes_handler(struct pt_regs *regs)
                         if (p->break_handler && p->break_handler(p, regs)) {
                                 goto ss_probe;
                         }
+                } else {
+                        /* Not our break */
+                        goto no_kprobe;
                 }
         }
 
@@ -515,7 +519,7 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
         struct die_args *args = (struct die_args *)data;
         switch(val) {
         case DIE_BREAK:
-                if (pre_kprobes_handler(args->regs))
+                if (pre_kprobes_handler(args))
                         return NOTIFY_STOP;
                 break;
         case DIE_SS: