Subject: Re: netfilter: active obj WARN when cleaning up

From: Bart Van Assche <[email-masked]>
Date: Thu, 19 Dec 2013 13:12:41 +0100

On 12/17/13 20:53, Sasha Levin wrote:
> I'm still seeing warnings with this patch applied:
> 
> [   24.900482] WARNING: CPU: 12 PID: 3654 at lib/debugobjects.c:260
> debug_print_object+
> 0x8d/0xb0()
> [   24.900482] ODEBUG: free active (active state 0) object type:
> timer_list hint: delay
> ed_work_timer_fn+0x0/0x20
> [   24.900482] Modules linked in:
> [   24.900482] CPU: 12 PID: 3654 Comm: kworker/12:1 Tainted: G       
> W    3.13.0-rc4-n
> ext-20131217-sasha-00013-ga878504-dirty #4149
> [   24.900482] Workqueue: events kobject_delayed_cleanup
> [   24.900482]  0000000000000104 ffff8804f429bae8 ffffffff8439501c
> ffffffff8555a92c
> [   24.900482]  ffff8804f429bb38 ffff8804f429bb28 ffffffff8112f8ac
> ffff8804f429bb58
> [   24.900482]  ffffffff856a9413 ffff880826333530 ffffffff85c68c40
> ffffffff8801bb58
> [   24.900482] Call Trace:
> [   24.900482]  [<ffffffff8439501c>] dump_stack+0x52/0x7f
> [   24.900482]  [<ffffffff8112f8ac>] warn_slowpath_common+0x8c/0xc0
> [   24.900482]  [<ffffffff8112f996>] warn_slowpath_fmt+0x46/0x50
> [   24.900482]  [<ffffffff81adb50d>] debug_print_object+0x8d/0xb0
> [   24.900482]  [<ffffffff81153090>] ? __queue_work+0x3f0/0x3f0
> [   24.900482]  [<ffffffff81adbd15>] __debug_check_no_obj_freed+0xa5/0x220
> [   24.900482]  [<ffffffff832b1acb>] ? rtc_device_release+0x2b/0x40
> [   24.900482]  [<ffffffff832b1acb>] ? rtc_device_release+0x2b/0x40
> [   24.900482]  [<ffffffff81adbea5>] debug_check_no_obj_freed+0x15/0x20
> [   24.900482]  [<ffffffff812ad54f>] kfree+0x21f/0x2e0
> [   24.900482]  [<ffffffff832b1acb>] rtc_device_release+0x2b/0x40
> [   24.900482]  [<ffffffff8207efd5>] device_release+0x65/0xc0
> [   24.900482]  [<ffffffff81ab05e5>] kobject_cleanup+0x145/0x190
> [   24.900482]  [<ffffffff81ab063d>] kobject_delayed_cleanup+0xd/0x10
> [   24.900482]  [<ffffffff81153a60>] process_one_work+0x320/0x530
> [   24.900482]  [<ffffffff81153940>] ? process_one_work+0x200/0x530
> [   24.900482]  [<ffffffff81155fe5>] worker_thread+0x215/0x350
> [   24.900482]  [<ffffffff81155dd0>] ? manage_workers+0x180/0x180
> [   24.900482]  [<ffffffff8115c9c5>] kthread+0x105/0x110
> [   24.900482]  [<ffffffff8115c8c0>] ? set_kthreadd_affinity+0x30/0x30
> [   24.900482]  [<ffffffff843a5e7c>] ret_from_fork+0x7c/0xb0
> [   24.900482]  [<ffffffff8115c8c0>] ? set_kthreadd_affinity+0x30/0x30
> [   24.900482] ---[ end trace 45529ebf79b2573e ]---

Can anyone tell me whether the patch below makes sense ? Please note
that I'm not familiar with the timer subsystem.

diff --git a/kernel/timer.c b/kernel/timer.c
index accfd24..828b666 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -969,6 +969,8 @@ int del_timer(struct timer_list *timer)
                base = lock_timer_base(timer, &flags);
                ret = detach_if_pending(timer, base, true);
                spin_unlock_irqrestore(&base->lock, flags);
+       } else {
+               debug_deactivate(timer);
        }

        return ret;

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to [email-masked].  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"[email-masked]"> [email-masked] </a>