INFO: task syz-executor.4:22000 can't die for more than 143 seconds. task:syz-executor.4 state:D stack:27224 pid:22000 ppid: 8510 flags:0x00004004 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:2211 do_new_mount_fc fs/namespace.c:2839 [inline] do_new_mount fs/namespace.c:2898 [inline] path_mount+0x1678/0x1e70 fs/namespace.c:3227 do_mount fs/namespace.c:3240 [inline] __do_sys_mount fs/namespace.c:3448 [inline] __se_sys_mount fs/namespace.c:3425 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3425 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e159 RSP: 002b:00007f290c1f0c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045e159 RDX: 0000000020002000 RSI: 00000000200042c0 RDI: 0000000000000000 RBP: 000000000119bfd0 R08: 0000000020002140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007fff80ed6eef R14: 00007f290c1f19c0 R15: 000000000119bf8c INFO: task syz-executor.4:22000 blocked for more than 143 seconds. Not tainted 5.10.0-next-20201215-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:27224 pid:22000 ppid: 8510 flags:0x00004004 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:2211 do_new_mount_fc fs/namespace.c:2839 [inline] do_new_mount fs/namespace.c:2898 [inline] path_mount+0x1678/0x1e70 fs/namespace.c:3227 do_mount fs/namespace.c:3240 [inline] __do_sys_mount fs/namespace.c:3448 [inline] __se_sys_mount fs/namespace.c:3425 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3425 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e159 RSP: 002b:00007f290c1f0c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045e159 RDX: 0000000020002000 RSI: 00000000200042c0 RDI: 0000000000000000 RBP: 000000000119bfd0 R08: 0000000020002140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007fff80ed6eef R14: 00007f290c1f19c0 R15: 000000000119bf8c INFO: task syz-executor.4:22007 can't die for more than 144 seconds. task:syz-executor.4 state:R running task stack:26992 pid:22007 ppid: 8510 flags:0x00004006 Call Trace: Showing all locks held in the system: 1 lock held by khungtaskd/1665: #0: ffffffff8b78f920 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x28c kernel/locking/lockdep.c:6254 1 lock held by in:imklog/8186: #0: ffff888020d2d770 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:923 1 lock held by syz-executor.4/22000: #0: ffff88806b308810 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] #0: ffff88806b308810 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lock_mount+0x8a/0x2e0 fs/namespace.c:2211 4 locks held by syz-executor.4/22007: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1665 Comm: khungtaskd Not tainted 5.10.0-next-20201215-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: 11308 Comm: kworker/u4:6 Not tainted 5.10.0-next-20201215-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:hlock_class kernel/locking/lockdep.c:198 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4506 [inline] RIP: 0010:__lock_acquire+0x3be/0x54b0 kernel/locking/lockdep.c:4782 Code: 45 89 4c 24 20 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 9f 11 00 00 8b 84 24 38 01 00 00 41 89 44 24 24 <4c> 8b 6c 24 08 be 08 00 00 00 41 81 e5 ff 1f 00 00 4c 89 e8 48 c1 RSP: 0018:ffffc9000353f9f0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801a050a04 RBP: ffff88801a050000 R08: 0000000000000001 R09: 000000000002002c R10: 0000000000000050 R11: 0000000000000000 R12: ffff88801a0509e0 R13: 0000000000000000 R14: ffffffff8b78f920 R15: 0000000000020000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562857fa7180 CR3: 000000002c2e9000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x750 kernel/locking/lockdep.c:5402 rcu_lock_acquire include/linux/rcupdate.h:253 [inline] rcu_read_lock include/linux/rcupdate.h:642 [inline] batadv_nc_process_nc_paths.part.0+0xec/0x3e0 net/batman-adv/network-coding.c:683 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:675 [inline] batadv_nc_worker+0xb2b/0xe80 net/batman-adv/network-coding.c:724 process_one_work+0x98d/0x1630 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296