aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorKUMANO Syuhei <kumano.prog@gmail.com>2010-08-15 15:18:04 +0900
committerIngo Molnar <mingo@elte.hu>2010-08-19 12:49:56 +0200
commit737480a0d525dae13306296da08029dff545bc72 (patch)
treee769b99529b60a55b6a9ef80bf38c8f1937cf3cc
parentf2036884400a1d867eae992681ecfd3e6725ece8 (diff)
downloadlinux-stericsson-737480a0d525dae13306296da08029dff545bc72.tar.gz
kprobes/x86: Fix the return address of multiple kretprobes
Fix the return address of subsequent kretprobes when multiple kretprobes are set on the same function. For example: # cd /sys/kernel/debug/tracing # echo "r:event1 sys_symlink" > kprobe_events # echo "r:event2 sys_symlink" >> kprobe_events # echo 1 > events/kprobes/enable # ln -s /tmp/foo /tmp/bar (without this patch) # cat trace ln-897 [000] 20404.133727: event1: (kretprobe_trampoline+0x0/0x4c <- sys_symlink) ln-897 [000] 20404.133747: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink) (with this patch) # cat trace ln-740 [000] 13799.491076: event1: (system_call_fastpath+0x16/0x1b <- sys_symlink) ln-740 [000] 13799.491096: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink) Signed-off-by: KUMANO Syuhei <kumano.prog@gmail.com> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> LKML-Reference: <1281853084.3254.11.camel@camp10-laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/kernel/kprobes.c25
1 files changed, 22 insertions, 3 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 1bfb6cf4dd55..770ebfb349e9 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -709,6 +709,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
+ kprobe_opcode_t *correct_ret_addr = NULL;
INIT_HLIST_HEAD(&empty_rp);
kretprobe_hash_lock(current, &head, &flags);
@@ -740,14 +741,34 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
/* another task is sharing our hash bucket */
continue;
+ orig_ret_address = (unsigned long)ri->ret_addr;
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
+ correct_ret_addr = ri->ret_addr;
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
if (ri->rp && ri->rp->handler) {
__get_cpu_var(current_kprobe) = &ri->rp->kp;
get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
+ ri->ret_addr = correct_ret_addr;
ri->rp->handler(ri, regs);
__get_cpu_var(current_kprobe) = NULL;
}
- orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
@@ -759,8 +780,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
break;
}
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {