From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
Masami Hiramatsu <mhiramat@redhat.com>,
Jim Keniston <jkenisto@us.ibm.com>,
bharata@linux.vnet.ibm.com
Subject: [PATCH] Kprobes: Fix locking imbalance in kretprobes
Date: Wed, 18 Mar 2009 17:06:21 +0530 [thread overview]
Message-ID: <20090318113621.GB4129@in.ibm.com> (raw)
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 <ananth@in.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
kernel/kprobes.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
Index: utrace-16mar/kernel/kprobes.c
===================================================================
--- utrace-16mar.orig/kernel/kprobes.c
+++ utrace-16mar/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);
next reply other threads:[~2009-03-18 11:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-18 11:36 Ananth N Mavinakayanahalli [this message]
2009-03-18 11:51 ` Ingo Molnar
2009-03-18 12:25 ` Ananth N Mavinakayanahalli
2009-03-18 11:54 ` [tip:tracing/kprobes] kprobes: " Ananth N Mavinakayanahalli
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