[syzbot] INFO: task hung in r871xu_dev_remove

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syzbot

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Dec 9, 2021, 1:27:27 AM12/9/21
to Larry....@lwfinger.net, florian.c....@googlemail.com, gre...@linuxfoundation.org, linux-...@vger.kernel.org, linux-...@lists.linux.dev, linu...@vger.kernel.org, paskr...@gmail.com, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: d598c3c46ea6 Merge 5.16-rc4 into usb-next
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=14cf0e55b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c6df5f09a0b9c823
dashboard link: https://syzkaller.appspot.com/bug?extid=f39c1dad0b7db49ca4a8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f39c1d...@syzkaller.appspotmail.com

INFO: task kworker/0:6:4133 blocked for more than 143 seconds.
Not tainted 5.16.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:6 state:D stack:21848 pid: 4133 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0x931/0x2320 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6385
__mutex_lock_common kernel/locking/mutex.c:680 [inline]
__mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:740
unregister_netdev+0xe/0x20 net/core/dev.c:11138
r871xu_dev_remove+0x24f/0x2c0 drivers/staging/rtl8712/usb_intf.c:599
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x40b/0x500 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

Showing all locks held in the system:
6 locks held by kworker/0:0/5:
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc9000005fdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88810cd40220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88810cd40220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff888130eb0220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff888130eb0220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#4: ffff888112be81a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff888112be81a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#5: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
1 lock held by khungtaskd/25:
#0: ffffffff87891640 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
6 locks held by kworker/1:2/69:
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc900009a7db0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88810ce9e220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88810ce9e220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff888117a52220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff888117a52220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#4: ffff888117a511a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff888117a511a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#5: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
6 locks held by kworker/0:2/704:
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90001f37db0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88810cdbe220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88810cdbe220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff888139190220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff888139190220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#4: ffff88811292d1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88811292d1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#5: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_register_hw+0x1b52/0x3ed0 net/mac80211/main.c:1245
3 locks held by kworker/0:3/1129:
#0: ffff88810deff938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88810deff938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88810deff938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88810deff938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88810deff938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88810deff938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90002c27db0 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4595
2 locks held by dhcpcd/1205:
#0: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x1b3/0x1ca0 net/ipv4/devinet.c:1068
#1: ffff888104fa4de0 (&padapter->mutex_start){+.+.}-{3:3}, at: netdev_open+0x2e/0x6c0 drivers/staging/rtl8712/os_intfs.c:375
2 locks held by getty/1229:
#0: ffff88810e389098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
#1: ffffc900000432e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
3 locks held by udevd/3986:
#0: ffff88810beedc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
#0: ffff88810beedc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
#1: ffff88811696ebd0 (kn->active#49){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
#1: ffff88811696ebd0 (kn->active#49){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
#2: ffff888139190220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
#2: ffff888139190220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
6 locks held by kworker/1:3/3999:
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90001737db0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88810cdd6220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88810cdd6220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff888103bf7220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff888103bf7220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#4: ffff8881151001a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff8881151001a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#5: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
6 locks held by kworker/1:4/4010:
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc900019c7db0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88810bab6220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88810bab6220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff88810a4ae220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff88810a4ae220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#4: ffff88811d57b1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88811d57b1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
#5: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
3 locks held by udevd/4012:
#0: ffff8881158fb488 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
#0: ffff8881158fb488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
#1: ffff88813a213cb8 (kn->active#49){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
#1: ffff88813a213cb8 (kn->active#49){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
#2: ffff88810a4ae220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
#2: ffff88810a4ae220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
3 locks held by udevd/4015:
#0: ffff8881392a2888 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
#0: ffff8881392a2888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
#1: ffff8881051cc748 (kn->active#49){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
#1: ffff8881051cc748 (kn->active#49){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
#2: ffff888103bf7220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
#2: ffff888103bf7220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
6 locks held by kworker/0:6/4133:
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888107da7938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc900028cfdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88810cdba220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88810cdba220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff88811a725220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff88811a725220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff88810b5171a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88810b5171a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff88810b5171a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff88810b5171a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
#5: ffffffff8886a7a8 (rtnl_mutex){+.+.}-{3:3}, at: unregister_netdev+0xe/0x20 net/core/dev.c:11138
2 locks held by kworker/0:7/5061:
#0: ffff888100066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888100066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888100066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888100066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888100066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888100066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc900013dfdb0 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
3 locks held by udevd/6728:
#0: ffff88810dadfc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
#0: ffff88810dadfc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
#1: ffff88810c392bd0 (kn->active#49){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
#1: ffff88810c392bd0 (kn->active#49){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
#2: ffff888130eb0220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
#2: ffff888130eb0220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
4 locks held by syz-executor.2/13210:
#0: ffff88810e8ac438 (sb_writers#4){.+.+}-{0:0}, at: ioctl_setflags fs/ioctl.c:729 [inline]
#0: ffff88810e8ac438 (sb_writers#4){.+.+}-{0:0}, at: do_vfs_ioctl+0xe36/0x15d0 fs/ioctl.c:843
#1: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
#1: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x148/0xb70 fs/ioctl.c:685
#2: ffff88810e8aebd0 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ind_migrate+0x237/0x840 fs/ext4/migrate.c:623
#3: ffffffff87899f68 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#3: ffffffff87899f68 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4fa/0x620 kernel/rcu/tree_exp.h:836
3 locks held by syz-executor.2/13211:
#0: ffff8881112ead70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:994
#1: ffff88810e8ac438 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0x12d/0x250 fs/read_write.c:643
#2: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
#2: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_dio_write_iter fs/ext4/file.c:510 [inline]
#2: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_file_write_iter+0x375/0x19b0 fs/ext4/file.c:679
1 lock held by syz-executor.2/13212:
#0: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
#0: ffff888131765c40 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: process_measurement+0x17c0/0x1920 security/integrity/ima/ima_main.c:241
3 locks held by syz-executor.5/13215:
#0: ffff88810e8ac438 (sb_writers#4){.+.+}-{0:0}, at: ioctl_setflags fs/ioctl.c:729 [inline]
#0: ffff88810e8ac438 (sb_writers#4){.+.+}-{0:0}, at: do_vfs_ioctl+0xe36/0x15d0 fs/ioctl.c:843
#1: ffff88813146ab30 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
#1: ffff88813146ab30 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x148/0xb70 fs/ioctl.c:685
#2: ffff88810e8aebd0 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ind_migrate+0x237/0x840 fs/ext4/migrate.c:623
1 lock held by syz-executor.5/13216:
#0: ffff88813146ab30 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
#0: ffff88813146ab30 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: process_measurement+0x17c0/0x1920 security/integrity/ima/ima_main.c:241
1 lock held by syz-executor.5/13217:
#0: ffff88813146ab30 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline]
#0: ffff88813146ab30 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: process_measurement+0x17c0/0x1920 security/integrity/ima/ima_main.c:241

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 25 Comm: khungtaskd Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
watchdog+0xc1d/0xf50 kernel/hung_task.c:295
kthread+0x40b/0x500 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1168 Comm: udevd Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:from_kuid_munged+0x0/0x130 kernel/user_namespace.c:436
Code: 00 48 8b 4c 24 58 65 48 2b 0c 25 28 00 00 00 75 10 48 83 c4 60 5b 5d 41 5c c3 e8 9b bf 32 00 eb c2 e8 84 4f 8e 04 0f 1f 40 00 <41> 54 49 89 fc 55 48 bd 00 00 00 00 00 fc ff df 53 48 83 ec 60 48
RSP: 0018:ffffc90000947ca0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90000947e20 RCX: 0000000000000000
RDX: 1ffff92000128fca RSI: 0000000000000000 RDI: ffffffff877562e0
RBP: 1ffff92000128f95 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff817852a1 R11: 0000000000000000 R12: 00007ffe89e9cf50
R13: ffff888110ce5400 R14: 00007f62917bf75a R15: 0000000000000000
FS: 00007f62915d2840(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f333a5b5008 CR3: 000000010d05b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
cp_new_stat+0x1ff/0x5b0 fs/stat.c:364
__do_sys_newfstatat+0x107/0x120 fs/stat.c:415
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f62917291da
Code: 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 0b 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 90 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 69 fc 0c 00 f7
RSP: 002b:00007ffe89e9cf48 EFLAGS: 00000206 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007f62917f6380 RCX: 00007f62917291da
RDX: 00007ffe89e9cf50 RSI: 00007f62917bf75a RDI: 000000000000000c
RBP: 0000559e56448a60 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000206 R12: 0000559e56448a60
R13: 0000000000000000 R14: 00007ffe89e9d528 R15: 0000000000003fff
</TASK>
----------------
Code disassembly (best guess):
0: 00 48 8b add %cl,-0x75(%rax)
3: 4c 24 58 rex.WR and $0x58,%al
6: 65 48 2b 0c 25 28 00 sub %gs:0x28,%rcx
d: 00 00
f: 75 10 jne 0x21
11: 48 83 c4 60 add $0x60,%rsp
15: 5b pop %rbx
16: 5d pop %rbp
17: 41 5c pop %r12
19: c3 retq
1a: e8 9b bf 32 00 callq 0x32bfba
1f: eb c2 jmp 0xffffffe3
21: e8 84 4f 8e 04 callq 0x48e4faa
26: 0f 1f 40 00 nopl 0x0(%rax)
* 2a: 41 54 push %r12 <-- trapping instruction
2c: 49 89 fc mov %rdi,%r12
2f: 55 push %rbp
30: 48 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%rbp
37: fc ff df
3a: 53 push %rbx
3b: 48 83 ec 60 sub $0x60,%rsp
3f: 48 rex.W


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

Pavel Skripkin

unread,
Dec 9, 2021, 1:22:33 PM12/9/21
to syzbot, Larry....@lwfinger.net, florian.c....@googlemail.com, gre...@linuxfoundation.org, linux-...@vger.kernel.org, linux-...@lists.linux.dev, linu...@vger.kernel.org, syzkall...@googlegroups.com
Seems like syz-executor ddosed the kernel. unregister_netdev() tries to
lock rtnl and there are 8 mentions of rtnl_mutex in "Showing all locks
held in the system" section.

Looks false-positive to me




With regards,
Pavel Skripkin

syzbot

unread,
Dec 15, 2021, 8:30:25 AM12/15/21
to Larry....@lwfinger.net, florian.c....@googlemail.com, gre...@linuxfoundation.org, linux-...@vger.kernel.org, linux-...@lists.linux.dev, linu...@vger.kernel.org, paskr...@gmail.com, syzkall...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: 5472f14a3742 Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1767bc25b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=fa556098924b78f0
dashboard link: https://syzkaller.appspot.com/bug?extid=f39c1dad0b7db49ca4a8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=174f3f51b00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17568e83b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f39c1d...@syzkaller.appspotmail.com

INFO: task kworker/1:1:25 blocked for more than 143 seconds.
Not tainted 5.16.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1 state:D stack:24888 pid: 25 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x174/0x270 kernel/sched/completion.c:138
r871xu_dev_remove+0x6e/0x2c0 drivers/staging/rtl8712/usb_intf.c:597
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
process_scheduled_works kernel/workqueue.c:2361 [inline]
worker_thread+0x85c/0x11f0 kernel/workqueue.c:2447
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
INFO: task kworker/1:2:137 blocked for more than 143 seconds.
Not tainted 5.16.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2 state:D stack:25016 pid: 137 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6385
__mutex_lock_common kernel/locking/mutex.c:680 [inline]
__mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:740
unregister_netdev+0xe/0x20 net/core/dev.c:11138
r871xu_dev_remove+0x24f/0x2c0 drivers/staging/rtl8712/usb_intf.c:599
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
process_scheduled_works kernel/workqueue.c:2361 [inline]
worker_thread+0x85c/0x11f0 kernel/workqueue.c:2447
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
INFO: task kworker/0:3:1136 blocked for more than 143 seconds.
Not tainted 5.16.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:3 state:D stack:24888 pid: 1136 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x174/0x270 kernel/sched/completion.c:138
r871xu_dev_remove+0x6e/0x2c0 drivers/staging/rtl8712/usb_intf.c:597
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
process_scheduled_works kernel/workqueue.c:2361 [inline]
worker_thread+0x85c/0x11f0 kernel/workqueue.c:2447
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
INFO: task kworker/1:0:3714 blocked for more than 144 seconds.
Not tainted 5.16.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0 state:D stack:24864 pid: 3714 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x174/0x270 kernel/sched/completion.c:138
r871xu_dev_remove+0x6e/0x2c0 drivers/staging/rtl8712/usb_intf.c:597
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
process_scheduled_works kernel/workqueue.c:2361 [inline]
worker_thread+0x85c/0x11f0 kernel/workqueue.c:2447
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
INFO: task kworker/1:3:3717 blocked for more than 144 seconds.
Not tainted 5.16.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:3 state:D stack:24488 pid: 3717 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x174/0x270 kernel/sched/completion.c:138
r871xu_dev_remove+0x6e/0x2c0 drivers/staging/rtl8712/usb_intf.c:597
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
process_scheduled_works kernel/workqueue.c:2361 [inline]
worker_thread+0x85c/0x11f0 kernel/workqueue.c:2447
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
INFO: task kworker/1:5:3722 blocked for more than 144 seconds.
Not tainted 5.16.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:5 state:D stack:24888 pid: 3722 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6385
__mutex_lock_common kernel/locking/mutex.c:680 [inline]
__mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:740
netdev_run_todo+0x6fa/0xa80 net/core/dev.c:10635
r871xu_dev_remove+0x24f/0x2c0 drivers/staging/rtl8712/usb_intf.c:599
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
__device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
device_release_driver_internal drivers/base/dd.c:1236 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1259
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
device_del+0x502/0xd60 drivers/base/core.c:3581
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5643 [inline]
hub_event+0x1c9c/0x4460 drivers/usb/core/hub.c:5725
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
process_scheduled_works kernel/workqueue.c:2361 [inline]
worker_thread+0x85c/0x11f0 kernel/workqueue.c:2447
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

Showing all locks held in the system:
5 locks held by kworker/1:1/25:
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90000dffdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff88801cfca220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88801cfca220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff888075ba6220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff888075ba6220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff88807b5081a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88807b5081a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff88807b5081a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff88807b5081a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
1 lock held by khungtaskd/27:
#0: ffffffff8bb83e60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
6 locks held by kworker/1:2/137:
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc9000209fdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff888148291220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff888148291220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff88807656e220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff88807656e220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff88807d3fb1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88807d3fb1a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff88807d3fb1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff88807d3fb1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
#5: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: unregister_netdev+0xe/0x20 net/core/dev.c:11138
5 locks held by kworker/0:3/1136:
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90004e6fdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff8881482e9220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff8881482e9220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff88807d1fa220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff88807d1fa220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff88807d1f91a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88807d1f91a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff88807d1f91a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff88807d1f91a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
2 locks held by dhcpcd/3184:
#0: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x1b3/0x1ca0 net/ipv4/devinet.c:1068
#1: ffff88807f254e60 (&padapter->mutex_start){+.+.}-{3:3}, at: netdev_open+0x2e/0x6c0 drivers/staging/rtl8712/os_intfs.c:375
2 locks held by getty/3283:
#0: ffff88802276f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
#1: ffffc90002b962e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
3 locks held by udevd/3682:
#0: ffff888022339c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
#0: ffff888022339c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
#1: ffff88801af0a748 (kn->active#50){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
#1: ffff88801af0a748 (kn->active#50){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
#2: ffff888075ba0220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
#2: ffff888075ba0220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
5 locks held by kworker/1:0/3714:
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90001fbfdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff888148301220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff888148301220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff88807f12e220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff88807f12e220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff8880155e61a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff8880155e61a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff8880155e61a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff8880155e61a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
5 locks held by kworker/1:3/3717:
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc9000291fdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff888148289220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff888148289220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff888075ba0220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff888075ba0220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff88807e0fd1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88807e0fd1a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff88807e0fd1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff88807e0fd1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
3 locks held by kworker/1:4/3720:
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc9000294fdb0 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
3 locks held by kworker/0:0/3721:
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc9000295fdb0 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
6 locks held by kworker/1:5/3722:
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88801578f938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc9000296fdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffff888148311220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff888148311220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4460 drivers/usb/core/hub.c:5671
#3: ffff88807e543220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#3: ffff88807e543220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
#4: ffff88807d3fe1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#4: ffff88807d3fe1a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
#4: ffff88807d3fe1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
#4: ffff88807d3fe1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
#5: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x6fa/0xa80 net/core/dev.c:10635
3 locks held by kworker/0:2/3729:
#0: ffff88814b0d8938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88814b0d8938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88814b0d8938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff88814b0d8938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff88814b0d8938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff88814b0d8938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc900029d7db0 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4595
3 locks held by kworker/1:8/3734:
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc900029ffdb0 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458
3 locks held by udevd/3737:
#0: ffff88807d251c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
#0: ffff88807d251c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
#1: ffff88801b95d490 (kn->active#50){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
#1: ffff88801b95d490 (kn->active#50){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
#2: ffff88807e543220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
#2: ffff88807e543220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
3 locks held by kworker/1:10/3926:
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
#0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
#1: ffffc90002b2fdb0 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
#2: ffffffff8d30d3a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x11/0x50 net/core/dev.c:10458

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
watchdog+0xc1d/0xf50 kernel/hung_task.c:295
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3709 Comm: syz-executor834 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:util_est_update kernel/sched/fair.c:4001 [inline]
RIP: 0010:dequeue_task_fair+0x4bf/0xea0 kernel/sched/fair.c:5742
Code: 42 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 6e 08 00 00 41 8b bf c0 01 00 00 85 ff 0f 84 0c fe ff ff 44 0f b6 74 24 08 41 83 e6 01 <45> 84 f6 0f 84 19 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 54
RSP: 0018:ffffc900020bfac0 EFLAGS: 00000093
RAX: ffff8880b9d39a80 RBX: 0000000000000005 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffff8880b9d39b5c RDI: ffff88801f9a9df0
RBP: ffff88801f9a9d00 R08: 0000000000000000 R09: ffff8880b9d39bc8
R10: 00000000000002ab R11: 0000000000000001 R12: 0000000000000009
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880b9d39b40
FS: 0000555555f6c400(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6cecc8bd40 CR3: 00000000780a3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
deactivate_task kernel/sched/core.c:2033 [inline]
__schedule+0xbe1/0x4940 kernel/sched/core.c:6207
schedule+0xd2/0x260 kernel/sched/core.c:6326
freezable_schedule include/linux/freezer.h:172 [inline]
do_nanosleep+0x24e/0x690 kernel/time/hrtimer.c:2044
hrtimer_nanosleep+0x1f9/0x4a0 kernel/time/hrtimer.c:2097
common_nsleep+0xa2/0xc0 kernel/time/posix-timers.c:1227
__do_sys_clock_nanosleep kernel/time/posix-timers.c:1267 [inline]
__se_sys_clock_nanosleep kernel/time/posix-timers.c:1245 [inline]
__x64_sys_clock_nanosleep+0x2f4/0x430 kernel/time/posix-timers.c:1245
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f6cecb20251
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 ba dc ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 f3 dc ff ff 48 8b 04 24 eb 97 66 2e 0f 1f
RSP: 002b:00007f6cecc8cd40 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 00000000001b25ad RCX: 00007f6cecb20251
RDX: 00007f6cecc8cd80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000000003f R08: 0000000000000000 R09: 00007ffed43bc080
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f6cecc8cdcc
R13: 00007f6cecc8ce00 R14: 00007f6cecc8cde0 R15: 000000000000003d
</TASK>
----------------
Code disassembly (best guess):
0: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax
5: 84 c0 test %al,%al
7: 74 08 je 0x11
9: 3c 03 cmp $0x3,%al
b: 0f 8e 6e 08 00 00 jle 0x87f
11: 41 8b bf c0 01 00 00 mov 0x1c0(%r15),%edi
18: 85 ff test %edi,%edi
1a: 0f 84 0c fe ff ff je 0xfffffe2c
20: 44 0f b6 74 24 08 movzbl 0x8(%rsp),%r14d
26: 41 83 e6 01 and $0x1,%r14d
* 2a: 45 84 f6 test %r14b,%r14b <-- trapping instruction
2d: 0f 84 19 02 00 00 je 0x24c
33: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
3a: fc ff df
3d: 48 rex.W
3e: 8b .byte 0x8b
3f: 54 push %rsp

Hillf Danton

unread,
Jan 24, 2022, 7:34:36 AM1/24/22
to syzbot, linux-...@vger.kernel.org, paskr...@gmail.com, syzkall...@googlegroups.com
On Wed, 15 Dec 2021 05:30:24 -0800
To fix multi cases of wait_for_completion(), add a atomic flag to adapter
and ensure only one disconnector using it, with no care for other locking
in the report now.

Only for thoughts now.

Hillf

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ 5472f14a3742

--- a/drivers/staging/rtl8712/drv_types.h
+++ b/drivers/staging/rtl8712/drv_types.h
@@ -163,6 +163,7 @@ struct _adapter {
struct usb_interface *pusb_intf;
struct mutex mutex_start;
struct completion rtl8712_fw_ready;
+ atomic_t disconnecting;
};

static inline u8 *myid(struct eeprom_priv *peepriv)
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -589,15 +589,29 @@ put_dev:
*/
static void r871xu_dev_remove(struct usb_interface *pusb_intf)
{
- struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
- struct usb_device *udev = interface_to_usbdev(pusb_intf);
- struct _adapter *padapter = netdev_priv(pnetdev);
+ struct net_device *pnetdev;
+ struct usb_device *udev;
+ struct _adapter *padapter = NULL;
+
+ rcu_read_lock();
+ pnetdev = usb_get_intfdata(pusb_intf);
+ if (pnetdev) {
+ padapter = netdev_priv(pnetdev);
+ if (1 == atomic_inc_return(&padapter->disconnecting))
+ usb_set_intfdata(pusb_intf, NULL);
+ else
+ padapter = NULL;
+ }
+ rcu_read_unlock();
+ if (padapter == NULL)
+ return;
+ synchronize_rcu();
+ udev = interface_to_usbdev(pusb_intf);

/* never exit with a firmware callback pending */
wait_for_completion(&padapter->rtl8712_fw_ready);
if (pnetdev->reg_state != NETREG_UNINITIALIZED)
unregister_netdev(pnetdev); /* will call netdev_close() */
- usb_set_intfdata(pusb_intf, NULL);
release_firmware(padapter->fw);
if (drvpriv.drv_registered)
padapter->surprise_removed = true;
--

syzbot

unread,
Jan 24, 2022, 7:48:10 AM1/24/22
to hda...@sina.com, linux-...@vger.kernel.org, paskr...@gmail.com, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+f39c1d...@syzkaller.appspotmail.com

Tested on:

commit: 5472f14a Merge tag 'for_linus' of git://git.kernel.org..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
kernel config: https://syzkaller.appspot.com/x/.config?x=22b66456935ee10
dashboard link: https://syzkaller.appspot.com/bug?extid=f39c1dad0b7db49ca4a8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=15c38248700000

Note: testing is done by a robot and is best-effort only.
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