INFO: task kworker/1:3:7153 blocked for more than 143 seconds.
      Not tainted 5.8.0-rc2-next-20200626-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:3     D27136  7153      2 0x00004000
Workqueue: afs afs_manage_cell
Call Trace:
 context_switch kernel/sched/core.c:3455 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4180
 schedule+0xd0/0x2a0 kernel/sched/core.c:4255
 bit_wait+0x12/0xa0 kernel/sched/wait_bit.c:199
 __wait_on_bit+0x60/0x190 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd5/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit include/linux/wait_bit.h:76 [inline]
 wait_for_key_construction+0x10b/0x140 security/keys/request_key.c:664
 request_key_tag+0x7a/0xb0 security/keys/request_key.c:705
 dns_query+0x257/0x6c3 net/dns_resolver/dns_query.c:128
 afs_dns_query+0xff/0x350 fs/afs/addr_list.c:249
 afs_update_cell fs/afs/cell.c:395 [inline]
 afs_manage_cell+0x88e/0x1100 fs/afs/cell.c:699
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Showing all locks held in the system:
3 locks held by kworker/1:0/17:
3 locks held by kworker/u4:3/94:
2 locks held by kworker/u4:4/185:
 #0: ffff8880aa031138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880aa031138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880aa031138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880aa031138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880aa031138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880aa031138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc900011a7da8 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
1 lock held by khungtaskd/1154:
 #0: ffffffff89bc3180 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779
1 lock held by systemd-udevd/3884:
 #0: ffff8880a2b65840 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x167/0x14d0 fs/block_dev.c:1578
1 lock held by in:imklog/6477:
 #0: ffff8880a26878b0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:928
2 locks held by syz-executor.0/6806:
 #0: ffff8880a2b65840 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x167/0x14d0 fs/block_dev.c:1578
 #1: ffffffff8a2af628 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1889
2 locks held by syz-executor.1/6913:
 #0: ffff88808aa9f8c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x167/0x14d0 fs/block_dev.c:1578
 #1: ffffffff8a2af628 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1889
1 lock held by syz-executor.3/7087:
 #0: ffff88808aa9a240 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x167/0x14d0 fs/block_dev.c:1578
2 locks held by kworker/1:3/7153:
 #0: ffff888214c40938 ((wq_completion)afs){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888214c40938 ((wq_completion)afs){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff888214c40938 ((wq_completion)afs){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff888214c40938 ((wq_completion)afs){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff888214c40938 ((wq_completion)afs){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff888214c40938 ((wq_completion)afs){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90005137da8 ((work_completion)(&cell->manager)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
1 lock held by syz-executor.5/7261:
 #0: ffff88808aa72940 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x167/0x14d0 fs/block_dev.c:1578
2 locks held by kworker/0:4/8058:
 #0: ffff8880aa023d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880aa023d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880aa023d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880aa023d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880aa023d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880aa023d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90016cefda8 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
1 lock held by systemd-udevd/20685:
 #0: ffff8880a2b65840 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x167/0x14d0 fs/block_dev.c:1578
2 locks held by systemd-udevd/20692:
 #0: ffff88808aa9a240 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1887
 #1: ffffffff8a2af628 (loop_ctl_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x88/0xe60 drivers/block/loop.c:1209
2 locks held by systemd-udevd/20696:
 #0: ffff88808aa72940 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1887
 #1: ffffffff8a2af628 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1908

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

NMI backtrace for cpu 0
CPU: 0 PID: 1154 Comm: khungtaskd Not tainted 5.8.0-rc2-next-20200626-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline]
 watchdog+0xd89/0xf30 kernel/hung_task.c:339
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6478 Comm: rs:main Q:Reg Not tainted 5.8.0-rc2-next-20200626-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:match_held_lock+0xa/0x170 kernel/locking/lockdep.c:4442
Code: c6 c0 b2 4b 88 48 c7 c7 00 b3 4b 88 e8 01 ae 5d f9 0f 0b eb c9 90 66 2e 0f 1f 84 00 00 00 00 00 48 39 77 10 0f 84 99 00 00 00 <66> f7 47 22 f0 ff 74 4f 55 53 48 83 ec 10 48 8b 46 08 48 85 c0 0f
RSP: 0018:ffffc90003997840 EFLAGS: 00000087
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000000016de
RDX: dffffc0000000000 RSI: ffffffff89bc3120 RDI: ffff88809f226b98
RBP: ffff88809f2262c0 R08: 0000000000000000 R09: ffff888214ab63c7
R10: fffffffffffff000 R11: 0000000000000000 R12: ffffffff89bc3120
R13: ffff88809f226b98 R14: ffff88809f226b98 R15: 0000000000000282
FS:  00007fca66de7700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4dae6ee010 CR3: 00000000a7b26000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __lock_is_held kernel/locking/lockdep.c:4733 [inline]
 lock_is_held_type+0x72/0xe0 kernel/locking/lockdep.c:4996
 lock_is_held include/linux/lockdep.h:264 [inline]
 ___might_sleep+0x22b/0x2f0 kernel/sched/core.c:6914
 __ext4_mark_inode_dirty+0xf4/0x910 fs/ext4/inode.c:5808
 ext4_dirty_inode+0xf3/0x130 fs/ext4/inode.c:5854
 __mark_inode_dirty+0x8cc/0x1300 fs/fs-writeback.c:2260
 generic_update_time+0x21c/0x370 fs/inode.c:1762
 update_time fs/inode.c:1775 [inline]
 file_update_time+0x434/0x520 fs/inode.c:1990
 file_modified fs/inode.c:2013 [inline]
 file_modified+0x7d/0xa0 fs/inode.c:1998
 ext4_write_checks fs/ext4/file.c:249 [inline]
 ext4_buffered_write_iter+0xfc/0x4a0 fs/ext4/file.c:265
 ext4_file_write_iter+0x1f3/0x13d0 fs/ext4/file.c:655
 call_write_iter include/linux/fs.h:1877 [inline]
 new_sync_write+0x422/0x650 fs/read_write.c:484
 __vfs_write+0xc9/0x100 fs/read_write.c:497
 vfs_write+0x268/0x5d0 fs/read_write.c:559
 ksys_write+0x12d/0x250 fs/read_write.c:612
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fca6982b1cd
Code: Bad RIP value.
RSP: 002b:00007fca66de6590 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fca5c00a050 RCX: 00007fca6982b1cd
RDX: 0000000000000584 RSI: 00007fca5c00a050 RDI: 0000000000000006
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007fca5c009dd0
R13: 00007fca66de65b0 R14: 000055ae9a41b360 R15: 0000000000000584