From f9d81f61c84aca693bc353dfef4b8c36c2e5e1b5 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Sun, 25 Sep 2011 19:46:22 +0200
Subject: [PATCH] ptrace: PTRACE_LISTEN forgets to unlock ->siglock
If PTRACE_LISTEN fails after lock_task_sighand() it doesn't drop ->siglock.
Reported-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/ptrace.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 9de3ecfd20f9..a70d2a5d8c7b 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -744,20 +744,17 @@ int ptrace_request(struct task_struct *child, long request,
break;
si = child->last_siginfo;
- if (unlikely(!si || si->si_code >> 8 != PTRACE_EVENT_STOP))
- break;
-
- child->jobctl |= JOBCTL_LISTENING;
-
- /*
- * If NOTIFY is set, it means event happened between start
- * of this trap and now. Trigger re-trap immediately.
- */
- if (child->jobctl & JOBCTL_TRAP_NOTIFY)
- signal_wake_up(child, true);
-
+ if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
+ child->jobctl |= JOBCTL_LISTENING;
+ /*
+ * If NOTIFY is set, it means event happened between
+ * start of this trap and now. Trigger re-trap.
+ */
+ if (child->jobctl & JOBCTL_TRAP_NOTIFY)
+ signal_wake_up(child, true);
+ ret = 0;
+ }
unlock_task_sighand(child, &flags);
- ret = 0;
break;
case PTRACE_DETACH: /* detach a process that was attached. */