INFO: task kworker/1:2:23048 blocked for more than 143 seconds. Not tainted 5.5.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:2 D26936 23048 2 0x80004000 Workqueue: events kernfs_notify_workfn Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 kernfs_notify_workfn+0xe0/0x480 fs/kernfs/file.c:882 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 3 locks held by init/1: 1 lock held by khungtaskd/1121: #0: ffffffff899a3f00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 3 locks held by rsyslogd/9423: #0: ffff888091a86868 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 #1: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 #2: ffffffff899a3f00 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:435 [inline] #2: ffffffff899a3f00 (rcu_read_lock){....}, at: update_curr+0x2ea/0x8d0 kernel/sched/fair.c:859 3 locks held by cron/9463: 2 locks held by getty/9513: #0: ffff88809dffa090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000183b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9514: #0: ffff8880945ca090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9515: #0: ffff888094be9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000181b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9516: #0: ffff888094bea090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000184b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9517: #0: ffff8880a84ba090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000182b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9518: #0: ffff88809dff9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000185b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9519: #0: ffff8880a06af090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 3 locks held by sshd/9533: #0: ffff888091ab55a8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 #1: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 #2: ffffffff899a3f00 (rcu_read_lock){....}, at: mem_cgroup_iter+0x101/0x5f0 mm/memcontrol.c:1011 4 locks held by syz-fuzzer/9535: 3 locks held by syz-fuzzer/9536: 2 locks held by syz-fuzzer/9537: #0: ffff888096a083a8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 #1: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 1 lock held by syz-fuzzer/9540: #0: ffff888096a083a8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 1 lock held by syz-fuzzer/15681: #0: ffff888096a083a8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 4 locks held by syz-executor.1/9556: #0: ffff8880a944a9d8 (&mm->mmap_sem#2){++++}, at: do_user_addr_fault arch/x86/mm/fault.c:1382 [inline] #0: ffff8880a944a9d8 (&mm->mmap_sem#2){++++}, at: __do_page_fault+0x33c/0xd80 arch/x86/mm/fault.c:1506 #1: ffffffff89a5bee0 (memcg_oom_lock#2){+.+.}, at: mem_cgroup_oom mm/memcontrol.c:1802 [inline] #1: ffffffff89a5bee0 (memcg_oom_lock#2){+.+.}, at: try_charge+0xa33/0x14d0 mm/memcontrol.c:2504 #2: ffffffff89a18620 (oom_lock){+.+.}, at: mem_cgroup_out_of_memory+0xa4/0x240 mm/memcontrol.c:1569 #3: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 2 locks held by syz-executor.0/16759: #0: ffff88808ba413e8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 #1: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 3 locks held by kworker/1:2/23048: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc90005537dc0 (kernfs_notify_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff89aa3d20 (kernfs_mutex){+.+.}, at: kernfs_notify_workfn+0xe0/0x480 fs/kernfs/file.c:882 3 locks held by kworker/u4:2/24620: #0: ffff8880ae937358 (&rq->lock){-.-.}, at: newidle_balance+0xa28/0xe80 kernel/sched/fair.c:10177 #1: ffffffff899a3f00 (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:5729 #2: ffff8880ae927258 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:936 3 locks held by udevd/29576: #0: ffff88814980aa00 (&type->i_mutex_dir_key#5){++++}, at: inode_lock_shared include/linux/fs.h:801 [inline] #0: ffff88814980aa00 (&type->i_mutex_dir_key#5){++++}, at: lookup_slow fs/namei.c:1680 [inline] #0: ffff88814980aa00 (&type->i_mutex_dir_key#5){++++}, at: walk_component+0x7ad/0xc90 fs/namei.c:1801 #1: ffffffff89aa3d20 (kernfs_mutex){+.+.}, at: kernfs_iop_lookup+0x4f/0x230 fs/kernfs/dir.c:1087 #2: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 1 lock held by syz-executor.1/29997: #0: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 2 locks held by syz-executor.0/30058: #0: ffff88808ba413e8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:5976 #1: ffffffff89a40580 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 2 locks held by kworker/1:1/30061: #0: ffff8880ae937358 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1215 [inline] #0: ffff8880ae937358 (&rq->lock){-.-.}, at: __schedule+0x232/0x1f90 kernel/sched/core.c:4029 #1: ffffffff899a3f00 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:435 [inline] #1: ffffffff899a3f00 (rcu_read_lock){....}, at: update_curr+0x2ea/0x8d0 kernel/sched/fair.c:859 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1121 Comm: khungtaskd Not tainted 5.5.0-rc6-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 24620 Comm: kworker/u4:2 Not tainted 5.5.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_purge_orig RIP: 0010:mark_usage kernel/locking/lockdep.c:3583 [inline] RIP: 0010:__lock_acquire+0x137f/0x4a00 kernel/locking/lockdep.c:3909 Code: 00 00 4c 89 d6 4c 89 df 4c 89 95 40 ff ff ff 4c 89 9d 48 ff ff ff e8 80 d9 ff ff 85 c0 0f 84 87 fe ff ff 4c 8b 9d 48 ff ff ff <48> b8 00 00 00 00 00 fc ff df 4c 8b 95 40 ff ff ff 49 8d bb 80 08 RSP: 0000:ffffc9001434fa50 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 1ffffffff166701e RSI: 0000000000000008 RDI: ffffffff8b3380f0 RBP: ffffc9001434fb68 R08: 1ffffffff165e7b4 R09: fffffbfff165e7b5 R10: fffffbfff165e7b4 R11: ffff88809f5e8380 R12: 000000000000062e R13: ffff88809f5e8c8a R14: 0000000000000000 R15: 000000000004062e FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f76d7a14e40 CR3: 0000000028530000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_purge_orig_ref+0x189/0x1360 net/batman-adv/originator.c:1350 batadv_purge_orig+0x1b/0x70 net/batman-adv/originator.c:1379 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352