syzbot


INFO: task hung in flush_async_commits

Status: upstream: reported on 2024/10/03 20:44
Reported-by: syzbot+01f4019a1444198953d7@syzkaller.appspotmail.com
First crash: 48d, last: 48d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in flush_async_commits 2 107d 172d 0/3 auto-obsoleted due to no activity on 2024/11/14 00:01
upstream INFO: task hung in flush_async_commits (2) reiserfs 3 419d 487d 0/28 auto-obsoleted due to no activity on 2023/12/28 15:52
upstream INFO: task hung in flush_async_commits reiserfs 4 655d 706d 0/28 auto-obsoleted due to no activity on 2023/05/05 20:14

Sample crash report:
INFO: task kworker/0:12:4485 blocked for more than 143 seconds.
      Not tainted 6.1.112-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:12    state:D stack:0     pid:4485  ppid:2      flags:0x00000008
Workqueue: reiserfs/loop1 flush_async_commits
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6693
 __mutex_lock_common+0xbd8/0x21a0 kernel/locking/mutex.c:679
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
 flush_async_commits+0x44/0xc4 fs/reiserfs/journal.c:3551
 process_one_work+0x7ac/0x1404 kernel/workqueue.c:2292
 worker_thread+0x8e4/0xfec kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864

Showing all locks held in the system:
4 locks held by kworker/0:0/7:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff80001d0f7c20 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000dc79e0e0 (&type->s_umount_key#54){++++}-{3:3}, at: flush_old_commits+0xcc/0x2b8 fs/reiserfs/super.c:97
 #3: ffff0000de21f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
3 locks held by kworker/u4:0/9:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff80001d117c20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015ba50f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015ba58f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015ba4f20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
5 locks held by kworker/u4:3/132:
 #0: ffff0000c0845138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800020d77c20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017fe7150 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf4/0x994 net/core/net_namespace.c:566
 #3: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
 #4: ffff800015baa4f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #4: ffff800015baa4f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3e0/0x77c kernel/rcu/tree_exp.h:962
3 locks held by kworker/1:2/3763:
 #0: ffff0000d61b0938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000238d7c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by getty/4061:
 #0: ffff0000d690c098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001efc02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2198
3 locks held by kworker/0:6/4349:
 #0: ffff0000d61b0938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000216b7c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by kworker/0:7/4372:
 #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021717c20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
4 locks held by kworker/0:9/4438:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021927c20 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000c08540e0 (&type->s_umount_key#54){++++}-{3:3}, at: flush_old_commits+0xcc/0x2b8 fs/reiserfs/super.c:97
 #3: ffff0000f5b77090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
3 locks held by kworker/0:12/4485:
 #0: ffff0000f0c36138 ((wq_completion)reiserfs/loop1){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000213f7c20 ((work_completion)(&(&journal->j_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000de21f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
4 locks held by syz.1.102/4786:
4 locks held by syz.4.150/5200:
1 lock held by syz-executor/6062:
 #0: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e8/0xd94 net/core/rtnetlink.c:6118
4 locks held by syz-executor/6083:
5 locks held by syz-executor/6131:
 #0: ffff0000d8ba8460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x244/0x91c fs/read_write.c:580
 #1: ffff0000e9d59488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c8/0x48c fs/kernfs/file.c:325
 #2: ffff0000d0d4fae8 (kn->active#45){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1e4/0x48c fs/kernfs/file.c:326
 #3: ffff8000173b5768 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xec/0x39c drivers/net/netdevsim/bus.c:209
 #4: ffff0000fde040e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
 #4: ffff0000fde040e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1080 [inline]
 #4: ffff0000fde040e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xbc/0x724 drivers/base/dd.c:1283
1 lock held by syz.1.296/6173:
 #0: ffff800015baa4f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffff800015baa4f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x30c/0x77c kernel/rcu/tree_exp.h:962
1 lock held by syz-executor/6176:
 #0: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e8/0xd94 net/core/rtnetlink.c:6118
1 lock held by syz-executor/6180:
 #0: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff800017ff2f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e8/0xd94 net/core/rtnetlink.c:6118

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Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/03 20:43 linux-6.1.y aa4cd140bba5 d7906eff .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in flush_async_commits
* Struck through repros no longer work on HEAD.