INFO: task syz-executor.4:11144 can't die for more than 143 seconds. task:syz-executor.4 state:D stack:27072 pid:11144 ppid: 8511 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x8eb/0x21b0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 rwsem_down_write_slowpath+0x809/0x1220 kernel/locking/rwsem.c:1106 __down_write_common kernel/locking/rwsem.c:1261 [inline] __down_write_common kernel/locking/rwsem.c:1258 [inline] __down_write kernel/locking/rwsem.c:1270 [inline] down_write+0x132/0x150 kernel/locking/rwsem.c:1407 inode_lock include/linux/fs.h:773 [inline] lock_mount+0x8a/0x2e0 fs/namespace.c:2214 do_new_mount_fc fs/namespace.c:2842 [inline] do_new_mount fs/namespace.c:2901 [inline] path_mount+0x1678/0x1e70 fs/namespace.c:3230 do_mount fs/namespace.c:3243 [inline] __do_sys_mount fs/namespace.c:3451 [inline] __se_sys_mount fs/namespace.c:3428 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3428 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e149 RSP: 002b:00007f87e770fc68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045e149 RDX: 0000000020002100 RSI: 00000000200020c0 RDI: 0000000000000000 RBP: 000000000119bfd0 R08: 0000000020002140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffe5cffc5ef R14: 00007f87e77109c0 R15: 000000000119bf8c INFO: task syz-executor.4:11144 blocked for more than 143 seconds. Not tainted 5.10.0-next-20201223-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:27072 pid:11144 ppid: 8511 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x8eb/0x21b0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 rwsem_down_write_slowpath+0x809/0x1220 kernel/locking/rwsem.c:1106 __down_write_common kernel/locking/rwsem.c:1261 [inline] __down_write_common kernel/locking/rwsem.c:1258 [inline] __down_write kernel/locking/rwsem.c:1270 [inline] down_write+0x132/0x150 kernel/locking/rwsem.c:1407 inode_lock include/linux/fs.h:773 [inline] lock_mount+0x8a/0x2e0 fs/namespace.c:2214 do_new_mount_fc fs/namespace.c:2842 [inline] do_new_mount fs/namespace.c:2901 [inline] path_mount+0x1678/0x1e70 fs/namespace.c:3230 do_mount fs/namespace.c:3243 [inline] __do_sys_mount fs/namespace.c:3451 [inline] __se_sys_mount fs/namespace.c:3428 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3428 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e149 RSP: 002b:00007f87e770fc68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045e149 RDX: 0000000020002100 RSI: 00000000200020c0 RDI: 0000000000000000 RBP: 000000000119bfd0 R08: 0000000020002140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffe5cffc5ef R14: 00007f87e77109c0 R15: 000000000119bf8c INFO: task syz-executor.4:11154 can't die for more than 144 seconds. task:syz-executor.4 state:R running task stack:27440 pid:11154 ppid: 8511 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x8eb/0x21b0 kernel/sched/core.c:5078 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:5238 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:40 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:183 Showing all locks held in the system: 2 locks held by kworker/u4:4/237: 1 lock held by khungtaskd/1665: #0: ffffffff8b793ae0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x28c kernel/locking/lockdep.c:6254 1 lock held by in:imklog/8189: #0: ffff8880219659f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:949 1 lock held by syz-executor.4/11144: #0: ffff88807e9d0150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] #0: ffff88807e9d0150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lock_mount+0x8a/0x2e0 fs/namespace.c:2214 3 locks held by syz-executor.4/11154: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1665 Comm: khungtaskd Not tainted 5.10.0-next-20201223-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x3c/0xef lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 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+0xe75/0x1020 kernel/hung_task.c:338 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4251 Comm: kworker/1:2 Not tainted 5.10.0-next-20201223-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: 0x0 (events) RIP: 0010:__lock_release kernel/locking/lockdep.c:5148 [inline] RIP: 0010:lock_release+0x2ab/0x710 kernel/locking/lockdep.c:5457 Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e bb 03 00 00 66 83 6b 22 10 66 f7 43 22 f0 ff 0f 85 0c 01 00 00 4c 89 f2 44 8b 64 24 50 <48> b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 84 c0 74 08 RSP: 0018:ffffc900061afb80 EFLAGS: 00000046 RAX: 0000000000000003 RBX: ffff88801f8a89b8 RCX: ffffc900061afbd0 RDX: ffff88801f8a8988 RSI: 0000000000000000 RDI: ffff88801f8a89da RBP: 1ffff92000c35f72 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000002 R14: ffff88801f8a8988 R15: ffff88801f8a8000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2490bb0000 CR3: 000000001216b000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cgroup_account_cputime include/linux/cgroup.h:779 [inline] update_curr+0x2ef/0x880 kernel/sched/fair.c:870 dequeue_entity+0x23/0xe10 kernel/sched/fair.c:4316 dequeue_task_fair+0x12e/0xdd0 kernel/sched/fair.c:5614 dequeue_task kernel/sched/core.c:1610 [inline] deactivate_task kernel/sched/core.c:1624 [inline] __schedule+0xc15/0x21b0 kernel/sched/core.c:5035 schedule+0xcf/0x270 kernel/sched/core.c:5157 worker_thread+0x14c/0x1120 kernel/workqueue.c:2442 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296