-stable review patch. If anyone has any objections, please let us know.
---------------------
From: Ananth N Mavinakayanahalli <[email protected]>
upstream commit: f02b8624fedca39886b0eef770dca70c2f0749b3
Fix locking imbalance in kretprobes:
=====================================
[ BUG: bad unlock balance detected! ]
-------------------------------------
kthreadd/2 is trying to release lock (&rp->lock) at:
[<c06b3080>] pre_handler_kretprobe+0xea/0xf4
but there are no more locks to release!
other info that might help us debug this:
1 lock held by kthreadd/2:
#0: (rcu_read_lock){..--}, at: [<c06b2b24>] __atomic_notifier_call_chain+0x0/0x5a
stack backtrace:
Pid: 2, comm: kthreadd Not tainted 2.6.29-rc8 #1
Call Trace:
[<c06ae498>] ? printk+0xf/0x17
[<c06b3080>] ? pre_handler_kretprobe+0xea/0xf4
[<c044ce6c>] print_unlock_inbalance_bug+0xc3/0xce
[<c0444d4b>] ? clocksource_read+0x7/0xa
[<c04450a4>] ? getnstimeofday+0x5f/0xf6
[<c044a9ca>] ? register_lock_class+0x17/0x293
[<c044b72c>] ? mark_lock+0x1e/0x30b
[<c0448956>] ? tick_dev_program_event+0x4a/0xbc
[<c0498100>] ? __slab_alloc+0xa5/0x415
[<c06b2fbe>] ? pre_handler_kretprobe+0x28/0xf4
[<c06b3080>] ? pre_handler_kretprobe+0xea/0xf4
[<c044cf1b>] lock_release_non_nested+0xa4/0x1a5
[<c06b3080>] ? pre_handler_kretprobe+0xea/0xf4
[<c044d15d>] lock_release+0x141/0x166
[<c06b07dd>] _spin_unlock_irqrestore+0x19/0x50
[<c06b3080>] pre_handler_kretprobe+0xea/0xf4
[<c06b20b5>] kprobe_exceptions_notify+0x1c9/0x43e
[<c06b2b02>] notifier_call_chain+0x26/0x48
[<c06b2b5b>] __atomic_notifier_call_chain+0x37/0x5a
[<c06b2b24>] ? __atomic_notifier_call_chain+0x0/0x5a
[<c06b2b8a>] atomic_notifier_call_chain+0xc/0xe
[<c0442d0d>] notify_die+0x2d/0x2f
[<c06b0f9c>] do_int3+0x1f/0x71
[<c06b0e84>] int3+0x2c/0x34
[<c042d476>] ? do_fork+0x1/0x288
[<c040221b>] ? kernel_thread+0x71/0x79
[<c043ed1b>] ? kthread+0x0/0x60
[<c043ed1b>] ? kthread+0x0/0x60
[<c04040b8>] ? kernel_thread_helper+0x0/0x10
[<c043ec7f>] kthreadd+0xac/0x148
[<c043ebd3>] ? kthreadd+0x0/0x148
[<c04040bf>] kernel_thread_helper+0x7/0x10
Signed-off-by: Ananth N Mavinakayanahalli <[email protected]>
Tested-by: Bharata B Rao <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Jim Keniston <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
kernel/kprobes.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -912,10 +912,8 @@ static int __kprobes pre_handler_kretpro
ri->rp = rp;
ri->task = current;
- if (rp->entry_handler && rp->entry_handler(ri, regs)) {
- spin_unlock_irqrestore(&rp->lock, flags);
+ if (rp->entry_handler && rp->entry_handler(ri, regs))
return 0;
- }
arch_prepare_kretprobe(ri, regs);