From: Peter Wu <lekensteyn@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Kernel development list <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] writeback: fix NULL dereference when device is gone
Date: Tue, 20 Aug 2013 12:13:58 +0200 [thread overview]
Message-ID: <1755678.6GItDDY0bW@al> (raw)
In-Reply-To: <20130819230240.GA6869@mtj.dyndns.org>
On Monday 19 August 2013 19:02:40 Tejun Heo wrote:
> On Tue, Aug 20, 2013 at 12:45:53AM +0200, Peter Wu wrote:
> > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> > index 68851ff..6e38a8b 100644
> > --- a/fs/fs-writeback.c
> > +++ b/fs/fs-writeback.c
> > @@ -1007,7 +1007,8 @@ void bdi_writeback_workfn(struct work_struct *work)
> >
> > struct backing_dev_info *bdi = wb->bdi;
> > long pages_written;
> >
> > - set_worker_desc("flush-%s", dev_name(bdi->dev));
> > + if (bdi->dev)
> > + set_worker_desc("flush-%s", dev_name(bdi->dev));
>
> Hmmm... bdi->dev is cleared after bdi_wb_shutdown() so the work item
> should no longer be running. It seems like something is queueing the
> work item after shutdown and the proper fix would be finding out which
> and fixing it. Can you please verify whether adding
> WARN_ON(!bdi->dev) in bdi_wakeup_thread_delayed() trigger anything?
Initially I did not get any warnings, so I added more. The patch (on top of
v3.11-rc6-27-g94fc5d9 plus some unrelated r8169 patches):
---8<---
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 68851ff..64a4cf9 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1007,7 +1007,9 @@ void bdi_writeback_workfn(struct work_struct *work)
struct backing_dev_info *bdi = wb->bdi;
long pages_written;
- set_worker_desc("flush-%s", dev_name(bdi->dev));
+ WARN_ON(!bdi->dev);
+ if (bdi->dev)
+ set_worker_desc("flush-%s", dev_name(bdi->dev));
current->flags |= PF_SWAPWRITE;
if (likely(!current_is_workqueue_rescuer() ||
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index e04454c..6f754ed 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -290,6 +290,7 @@ void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi)
{
unsigned long timeout;
+ WARN_ON(!bdi->dev);
timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
mod_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
}
@@ -362,6 +363,7 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
* @bdi->bdi_list is empty telling bdi_Writeback_workfn() that @bdi
* is dying and its work_list needs to be drained no matter what.
*/
+ WARN_ON(!bdi->dev);
mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0);
flush_delayed_work(&bdi->wb.dwork);
WARN_ON(!list_empty(&bdi->work_list));
@@ -406,6 +408,10 @@ void bdi_unregister(struct backing_dev_info *bdi)
spin_unlock_bh(&bdi->wb_lock);
device_unregister(dev);
+ if (delayed_work_pending(&bdi->wb.dwork))
+ WARN(1, "bdi->dwork is pending!");
+ else
+ WARN(1, "in bdi_unregister");
}
}
EXPORT_SYMBOL(bdi_unregister);
--->8---
In order to reproduce, I used the command:
sudo dd if=/dev/zero of=/dev/sdc bs=1M count=300 &
sleep .1 && sudo tee /sys/bus/usb/devices/6-2/remove <<<1
=== serial console ===
[ 196.186205] usb 6-2: new SuperSpeed USB device number 2 using xhci_hcd
[ 196.208702] usb 6-2: Parent hub missing LPM exit latency info. Power management will be impacted.
[ 196.221963] usb 6-2: New USB device found, idVendor=1058, idProduct=0748
[ 196.228662] usb 6-2: New USB device strings: Mfr=1, Product=2, SerialNumber=5
[ 196.235791] usb 6-2: Product: My Passport 0748
[ 196.240234] usb 6-2: Manufacturer: Western Digital
[ 196.245025] usb 6-2: SerialNumber: 575842314133334E35383439
[ 196.252492] usb-storage 6-2:1.0: USB Mass Storage device detected
[ 196.258827] scsi13 : usb-storage 6-2:1.0
[ 197.263013] scsi 13:0:0:0: Direct-Access WD My Passport 0748 1022 PQ: 0 ANSI: 6
[ 197.271459] scsi 13:0:0:1: Enclosure WD SES Device 1022 PQ: 0 ANSI: 6
[ 197.279981] sd 13:0:0:0: Attached scsi generic sg3 type 0
[ 197.280207] sd 13:0:0:0: [sdc] 1953458176 512-byte logical blocks: (1.00 TB/931 GiB)
[ 197.280668] sd 13:0:0:0: [sdc] Write Protect is off
[ 197.280670] sd 13:0:0:0: [sdc] Mode Sense: 47 00 10 08
[ 197.281340] sd 13:0:0:0: [sdc] No Caching mode page present
[ 197.281341] sd 13:0:0:0: [sdc] Assuming drive cache: write through
[ 197.283092] sd 13:0:0:0: [sdc] No Caching mode page present
[ 197.283093] sd 13:0:0:0: [sdc] Assuming drive cache: write through
[ 197.283318] sdc: unknown partition table
[ 197.330898] scsi 13:0:0:1: Attached scsi generic sg4 type 13
[ 197.338824] sd 13:0:0:0: [sdc] No Caching mode page present
[ 197.344449] sd 13:0:0:0: [sdc] Assuming drive cache: write through
[ 197.350647] sd 13:0:0:0: [sdc] Attached SCSI disk
[ 245.972280] ------------[ cut here ]------------
[ 245.976904] WARNING: CPU: 3 PID: 2605 at /home/pc/Linux-src/linux/mm/backing-dev.c:414 bdi_unregister+0x107/0x1c0()
[ 245.978167] ------------[ cut here ]------------
[ 245.978170] WARNING: CPU: 1 PID: 2608 at /home/pc/Linux-src/linux/mm/backing-dev.c:293 bdi_wakeup_thread_delayed+0x5e/0x60()
[ 245.978189] Modules linked in: kvm_intel kvm dm_crypt binfmt_misc joydev snd_hda_codec_hdmi snd_hda_codec_realtek hid_logitech_dj hid_generic mxm_wmi nls_iso8859_1 snd_hda_intel snd_hda_codec usbhid hid snd_hwdep psmouse usb_storage snd_pcm serio_raw lpc_ich snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd wmi it87 mac_hid hwmon_vid coretemp soundcore snd_page_alloc r8169 eeprom_93cx6 mii pci_stub ahci libahci i915 drm_kms_helper drm video i2c_algo_bit
[ 245.978191] CPU: 1 PID: 2608 Comm: ata_id Tainted: G W 3.11.0-rc6-usbdbg-00030-g693d742-dirty #1
[ 245.978192] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z68X-UD3H-B3, BIOS U1l 03/08/2013
[ 245.978194] 0000000000000125 ffff8805d3a4fa98 ffffffff8165986e 00000000000060d0
[ 245.978196] 0000000000000000 ffff8805d3a4fad8 ffffffff81047acc ffff880602f6beb8
[ 245.978197] ffff8805fc024618 ffff880602f6be30 ffffffff81c58f80 ffff880602f6beb8
[ 245.978198] Call Trace:
[ 245.978202] [<ffffffff8165986e>] dump_stack+0x55/0x76
[ 245.978204] [<ffffffff81047acc>] warn_slowpath_common+0x8c/0xc0
[ 245.978206] [<ffffffff81047b1a>] warn_slowpath_null+0x1a/0x20
[ 245.978207] [<ffffffff811424fe>] bdi_wakeup_thread_delayed+0x5e/0x60
[ 245.978211] [<ffffffff811bdc71>] bdev_inode_switch_bdi+0xf1/0x160
[ 245.978212] [<ffffffff811bedd2>] __blkdev_get+0x372/0x4d0
[ 245.978214] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.978216] [<ffffffff811bf115>] blkdev_get+0x1e5/0x380
[ 245.978218] [<ffffffff8166551b>] ? _raw_spin_unlock+0x2b/0x50
[ 245.978219] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.978221] [<ffffffff811bf36f>] blkdev_open+0x5f/0x90
[ 245.978223] [<ffffffff81180cd6>] do_dentry_open+0x226/0x2a0
[ 245.978225] [<ffffffff81180fa5>] finish_open+0x35/0x50
[ 245.978227] [<ffffffff81192d9e>] do_last+0x48e/0x7a0
[ 245.978229] [<ffffffff81193174>] path_openat+0xc4/0x4e0
[ 245.978230] [<ffffffff81193d83>] do_filp_open+0x43/0xa0
[ 245.978232] [<ffffffff811a14a7>] ? __alloc_fd+0xa7/0x130
[ 245.978234] [<ffffffff81182422>] do_sys_open+0x132/0x220
[ 245.978236] [<ffffffff8118252e>] SyS_open+0x1e/0x20
[ 245.978238] [<ffffffff8166e802>] system_call_fastpath+0x16/0x1b
[ 245.978239] ---[ end trace 04d4f07eb5cc8c11 ]---
[ 245.979484] ------------[ cut here ]------------
[ 245.979487] WARNING: CPU: 1 PID: 2609 at /home/pc/Linux-src/linux/mm/backing-dev.c:293 bdi_wakeup_thread_delayed+0x5e/0x60()
[ 245.979500] Modules linked in: kvm_intel kvm dm_crypt binfmt_misc joydev snd_hda_codec_hdmi snd_hda_codec_realtek hid_logitech_dj hid_generic mxm_wmi nls_iso8859_1 snd_hda_intel snd_hda_codec usbhid hid snd_hwdep psmouse usb_storage snd_pcm serio_raw lpc_ich snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd wmi it87 mac_hid hwmon_vid coretemp soundcore snd_page_alloc r8169 eeprom_93cx6 mii pci_stub ahci libahci i915 drm_kms_helper drm video i2c_algo_bit
[ 245.979502] CPU: 1 PID: 2609 Comm: scsi_id Tainted: G W 3.11.0-rc6-usbdbg-00030-g693d742-dirty #1
[ 245.979502] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z68X-UD3H-B3, BIOS U1l 03/08/2013
[ 245.979504] 0000000000000125 ffff8805d391fa98 ffffffff8165986e 000000000000613d
[ 245.979506] 0000000000000000 ffff8805d391fad8 ffffffff81047acc ffff880602f6beb8
[ 245.979507] ffff8805fc024618 ffff880602f6be30 ffffffff81c58f80 ffff880602f6beb8
[ 245.979507] Call Trace:
[ 245.979510] [<ffffffff8165986e>] dump_stack+0x55/0x76
[ 245.979512] [<ffffffff81047acc>] warn_slowpath_common+0x8c/0xc0
[ 245.979513] [<ffffffff81047b1a>] warn_slowpath_null+0x1a/0x20
[ 245.979515] [<ffffffff811424fe>] bdi_wakeup_thread_delayed+0x5e/0x60
[ 245.979516] [<ffffffff811bdc71>] bdev_inode_switch_bdi+0xf1/0x160
[ 245.979518] [<ffffffff811bedd2>] __blkdev_get+0x372/0x4d0
[ 245.979520] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.979522] [<ffffffff811bf115>] blkdev_get+0x1e5/0x380
[ 245.979523] [<ffffffff8166551b>] ? _raw_spin_unlock+0x2b/0x50
[ 245.979525] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.979527] [<ffffffff811bf36f>] blkdev_open+0x5f/0x90
[ 245.979528] [<ffffffff81180cd6>] do_dentry_open+0x226/0x2a0
[ 245.979530] [<ffffffff81180fa5>] finish_open+0x35/0x50
[ 245.979531] [<ffffffff81192d9e>] do_last+0x48e/0x7a0
[ 245.979533] [<ffffffff81193174>] path_openat+0xc4/0x4e0
[ 245.979534] [<ffffffff81193d83>] do_filp_open+0x43/0xa0
[ 245.979536] [<ffffffff811a14a7>] ? __alloc_fd+0xa7/0x130
[ 245.979537] [<ffffffff81182422>] do_sys_open+0x132/0x220
[ 245.979539] [<ffffffff8118252e>] SyS_open+0x1e/0x20
[ 245.979541] [<ffffffff8166e802>] system_call_fastpath+0x16/0x1b
[ 245.979542] ---[ end trace 04d4f07eb5cc8c12 ]---
[ 245.980314] ------------[ cut here ]------------
[ 245.980317] WARNING: CPU: 2 PID: 2610 at /home/pc/Linux-src/linux/mm/backing-dev.c:293 bdi_wakeup_thread_delayed+0x5e/0x60()
[ 245.980330] Modules linked in: kvm_intel kvm dm_crypt binfmt_misc joydev snd_hda_codec_hdmi snd_hda_codec_realtek hid_logitech_dj hid_generic mxm_wmi nls_iso8859_1 snd_hda_intel snd_hda_codec usbhid hid snd_hwdep psmouse usb_storage snd_pcm serio_raw lpc_ich snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd wmi it87 mac_hid hwmon_vid coretemp soundcore snd_page_alloc r8169 eeprom_93cx6 mii pci_stub ahci libahci i915 drm_kms_helper drm video i2c_algo_bit
[ 245.980331] CPU: 2 PID: 2610 Comm: blkid Tainted: G W 3.11.0-rc6-usbdbg-00030-g693d742-dirty #1
[ 245.980332] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z68X-UD3H-B3, BIOS U1l 03/08/2013
[ 245.980334] 0000000000000125 ffff8805d6e93a98 ffffffff8165986e 00000000000061aa
[ 245.980335] 0000000000000000 ffff8805d6e93ad8 ffffffff81047acc ffff880602f6beb8
[ 245.980337] ffff8805fc024618 ffff880602f6be30 ffffffff81c58f80 ffff880602f6beb8
[ 245.980337] Call Trace:
[ 245.980339] [<ffffffff8165986e>] dump_stack+0x55/0x76
[ 245.980341] [<ffffffff81047acc>] warn_slowpath_common+0x8c/0xc0
[ 245.980343] [<ffffffff81047b1a>] warn_slowpath_null+0x1a/0x20
[ 245.980344] [<ffffffff811424fe>] bdi_wakeup_thread_delayed+0x5e/0x60
[ 245.980346] [<ffffffff811bdc71>] bdev_inode_switch_bdi+0xf1/0x160
[ 245.980348] [<ffffffff811bedd2>] __blkdev_get+0x372/0x4d0
[ 245.980349] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.980351] [<ffffffff811bf115>] blkdev_get+0x1e5/0x380
[ 245.980352] [<ffffffff8166551b>] ? _raw_spin_unlock+0x2b/0x50
[ 245.980354] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.980356] [<ffffffff811bf36f>] blkdev_open+0x5f/0x90
[ 245.980357] [<ffffffff81180cd6>] do_dentry_open+0x226/0x2a0
[ 245.980359] [<ffffffff81180fa5>] finish_open+0x35/0x50
[ 245.980360] [<ffffffff81192d9e>] do_last+0x48e/0x7a0
[ 245.980362] [<ffffffff81193174>] path_openat+0xc4/0x4e0
[ 245.980363] [<ffffffff81193d83>] do_filp_open+0x43/0xa0
[ 245.980365] [<ffffffff811a14a7>] ? __alloc_fd+0xa7/0x130
[ 245.980366] [<ffffffff81182422>] do_sys_open+0x132/0x220
[ 245.980368] [<ffffffff8118252e>] SyS_open+0x1e/0x20
[ 245.980369] [<ffffffff8166e802>] system_call_fastpath+0x16/0x1b
[ 245.980370] ---[ end trace 04d4f07eb5cc8c13 ]---
[ 245.981935] ------------[ cut here ]------------
[ 245.981938] WARNING: CPU: 2 PID: 2611 at /home/pc/Linux-src/linux/mm/backing-dev.c:293 bdi_wakeup_thread_delayed+0x5e/0x60()
[ 245.981951] Modules linked in: kvm_intel kvm dm_crypt binfmt_misc joydev snd_hda_codec_hdmi snd_hda_codec_realtek hid_logitech_dj hid_generic mxm_wmi nls_iso8859_1 snd_hda_intel snd_hda_codec usbhid hid snd_hwdep psmouse usb_storage snd_pcm serio_raw lpc_ich snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd wmi it87 mac_hid hwmon_vid coretemp soundcore snd_page_alloc r8169 eeprom_93cx6 mii pci_stub ahci libahci i915 drm_kms_helper drm video i2c_algo_bit
[ 245.981952] CPU: 2 PID: 2611 Comm: udisks-part-id Tainted: G W 3.11.0-rc6-usbdbg-00030-g693d742-dirty #1
[ 245.981953] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z68X-UD3H-B3, BIOS U1l 03/08/2013
[ 245.981955] 0000000000000125 ffff8805d6e97a98 ffffffff8165986e 0000000000006217
[ 245.981956] 0000000000000000 ffff8805d6e97ad8 ffffffff81047acc ffff880602f6beb8
[ 245.981957] ffff8805fc024618 ffff880602f6be30 ffffffff81c58f80 ffff880602f6beb8
[ 245.981958] Call Trace:
[ 245.981960] [<ffffffff8165986e>] dump_stack+0x55/0x76
[ 245.981962] [<ffffffff81047acc>] warn_slowpath_common+0x8c/0xc0
[ 245.981964] [<ffffffff81047b1a>] warn_slowpath_null+0x1a/0x20
[ 245.981965] [<ffffffff811424fe>] bdi_wakeup_thread_delayed+0x5e/0x60
[ 245.981967] [<ffffffff811bdc71>] bdev_inode_switch_bdi+0xf1/0x160
[ 245.981968] [<ffffffff811bedd2>] __blkdev_get+0x372/0x4d0
[ 245.981970] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.981972] [<ffffffff811bf115>] blkdev_get+0x1e5/0x380
[ 245.981973] [<ffffffff8166551b>] ? _raw_spin_unlock+0x2b/0x50
[ 245.981975] [<ffffffff811bf310>] ? blkdev_get_by_dev+0x60/0x60
[ 245.981977] [<ffffffff811bf36f>] blkdev_open+0x5f/0x90
[ 245.981978] [<ffffffff81180cd6>] do_dentry_open+0x226/0x2a0
[ 245.981980] [<ffffffff81180fa5>] finish_open+0x35/0x50
[ 245.981981] [<ffffffff81192d9e>] do_last+0x48e/0x7a0
[ 245.981983] [<ffffffff81193174>] path_openat+0xc4/0x4e0
[ 245.981984] [<ffffffff81193d83>] do_filp_open+0x43/0xa0
[ 245.981986] [<ffffffff811a14a7>] ? __alloc_fd+0xa7/0x130
[ 245.981987] [<ffffffff81182422>] do_sys_open+0x132/0x220
[ 245.981989] [<ffffffff8118252e>] SyS_open+0x1e/0x20
[ 245.981990] [<ffffffff8166e802>] system_call_fastpath+0x16/0x1b
[ 245.981991] ---[ end trace 04d4f07eb5cc8c14 ]---
[ 246.864116] in bdi_unregister
[ 246.866911] Modules linked in: kvm_intel kvm dm_crypt binfmt_misc joydev snd_hda_codec_hdmi snd_hda_codec_realtek hid_logitech_dj hid_generic mxm_wmi nls_iso8859_1 snd_hda_intel snd_hda_codec usbhid hid snd_hwdep psmouse usb_storage snd_pcm serio_raw lpc_ich snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd wmi it87 mac_hid hwmon_vid coretemp soundcore snd_page_alloc r8169 eeprom_93cx6 mii pci_stub ahci libahci i915 drm_kms_helper drm video i2c_algo_bit
[ 246.910673] CPU: 3 PID: 2605 Comm: tee Tainted: G W 3.11.0-rc6-usbdbg-00030-g693d742-dirty #1
[ 246.920049] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z68X-UD3H-B3, BIOS U1l 03/08/2013
[ 246.930300] 000000000000019e ffff8805d71c39b8 ffffffff8165986e ffff88061f38f418
[ 246.937763] ffff8805d71c3a08 ffff8805d71c39f8 ffffffff81047acc ffff8805fd7a0410
[ 246.945223] ffff8805fc024618 ffff8805fd7a0400 ffff8805fc0249d8 0000000000800020
[ 246.952683] Call Trace:
[ 246.955128] [<ffffffff8165986e>] dump_stack+0x55/0x76
[ 246.960261] [<ffffffff81047acc>] warn_slowpath_common+0x8c/0xc0
[ 246.966264] [<ffffffff81047bb6>] warn_slowpath_fmt+0x46/0x50
[ 246.972009] [<ffffffff8140ad17>] ? put_device+0x17/0x20
[ 246.977318] [<ffffffff81141d17>] bdi_unregister+0x107/0x1c0
[ 246.982977] [<ffffffff812f86eb>] del_gendisk+0xfb/0x260
[ 246.988287] [<ffffffff81459bd9>] sd_remove+0x79/0xe0
[ 246.993339] [<ffffffff8140f54f>] __device_release_driver+0x7f/0xf0
[ 246.999603] [<ffffffff8140f5e5>] device_release_driver+0x25/0x40
[ 247.005693] [<ffffffff8140ee47>] bus_remove_device+0x107/0x150
[ 247.011611] [<ffffffff8140c033>] device_del+0x133/0x1c0
[ 247.016922] [<ffffffff81455355>] __scsi_remove_device+0xc5/0xd0
[ 247.022925] [<ffffffff81453c3f>] scsi_forget_host+0x6f/0x80
[ 247.028584] [<ffffffff81448baa>] scsi_remove_host+0x7a/0x130
[ 247.034330] [<ffffffffa01fc6e3>] quiesce_and_remove_host+0x63/0xd0 [usb_storage]
[ 247.041805] [<ffffffffa01fc822>] usb_stor_disconnect+0x22/0x40 [usb_storage]
[ 247.048935] [<ffffffff814a9c23>] usb_unbind_interface+0x63/0x1b0
[ 247.055024] [<ffffffff8140f54f>] __device_release_driver+0x7f/0xf0
[ 247.061288] [<ffffffff8140f5e5>] device_release_driver+0x25/0x40
[ 247.067379] [<ffffffff8140ee47>] bus_remove_device+0x107/0x150
[ 247.073296] [<ffffffff8140c033>] device_del+0x133/0x1c0
[ 247.078609] [<ffffffff814a764f>] usb_disable_device+0xaf/0x200
[ 247.084526] [<ffffffff814a7f9c>] usb_set_configuration+0x14c/0x800
[ 247.090789] [<ffffffff814ad8ad>] ? usb_remove_store+0x2d/0x80
[ 247.096619] [<ffffffff814ad8e4>] usb_remove_store+0x64/0x80
[ 247.102278] [<ffffffff8140a908>] dev_attr_store+0x18/0x30
[ 247.107764] [<ffffffff811f8c86>] sysfs_write_file+0xe6/0x170
[ 247.113505] [<ffffffff811836ae>] vfs_write+0xce/0x200
[ 247.118646] [<ffffffff816625ca>] ? __schedule+0x3ca/0x870
[ 247.124129] [<ffffffff81183bb5>] SyS_write+0x55/0xa0
[ 247.129179] [<ffffffff8166e802>] system_call_fastpath+0x16/0x1b
[ 247.135181] ---[ end trace 04d4f07eb5cc8c15 ]---
[ 247.141812] usb 6-2: USB disconnect, device number 2
next prev parent reply other threads:[~2013-08-20 10:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-18 1:08 [3.11-rc5..] NULL pointer dereference in bdi_writeback_workfn Alan Stern
2013-08-19 22:45 ` [PATCH] writeback: fix NULL dereference when device is gone Peter Wu
2013-08-19 23:02 ` Tejun Heo
2013-08-20 10:13 ` Peter Wu [this message]
2013-08-20 13:33 ` Tejun Heo
2013-08-28 22:31 ` Peter Wu
2013-09-04 18:21 ` Tejun Heo
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