INFO: task syz-executor.0:11045 blocked for more than 143 seconds. Not tainted 5.11.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:28344 pid:11045 ppid: 8422 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x999/0xe70 kernel/sched/core.c:5078 schedule+0x14b/0x200 kernel/sched/core.c:5157 schedule_timeout+0x43/0x250 kernel/time/timer.c:1854 do_wait_for_common+0x266/0x3a0 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x43/0x50 kernel/sched/completion.c:138 flush_workqueue+0x704/0x1620 kernel/workqueue.c:2838 nbd_start_device_ioctl drivers/block/nbd.c:1332 [inline] __nbd_ioctl drivers/block/nbd.c:1393 [inline] nbd_ioctl+0x76d/0x940 drivers/block/nbd.c:1433 blkdev_ioctl+0x2d6/0x5f0 block/ioctl.c:576 block_ioctl+0xae/0xf0 fs/block_dev.c:1658 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x465d99 RSP: 002b:00007f367e74a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465d99 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 00000000004bcf27 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffff169cfbf R14: 00007f367e74a300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1647: #0: ffffffff8c711680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151 3 locks held by in:imklog/8114: #0: ffff888016016370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:947 #1: ffff8880b9c34758 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1320 [inline] #1: ffff8880b9c34758 (&rq->lock){-.-.}-{2:2}, at: __schedule+0xd8/0xe70 kernel/sched/core.c:4995 #2: ffffffff8c7d9e80 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151 3 locks held by kworker/u5:2/8438: #0: ffff88801c7c6138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: process_one_work+0x6f4/0xfc0 kernel/workqueue.c:2248 #1: ffffc90001a3fd78 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x733/0xfc0 kernel/workqueue.c:2250 #2: ffff88806e744120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1594 [inline] #2: ffff88806e744120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: ax25_recvmsg+0x86/0x740 net/ax25/af_ax25.c:1626 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1647 Comm: khungtaskd Not tainted 5.11.0-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+0x137/0x1be lib/dump_stack.c:120 nmi_cpu_backtrace+0x16c/0x190 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xce9/0xd30 kernel/hung_task.c:294 kthread+0x39a/0x3c0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4864 Comm: systemd-journal Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_memory_region+0x222/0x2f0 mm/kasan/generic.c:185 Code: 03 4d 89 cf 49 8d 5e 07 4d 85 f6 49 0f 49 de 48 83 e3 f8 49 29 de 74 11 45 0f b6 1f 45 84 db 75 64 49 ff c7 49 ff ce 75 ef 5b <41> 5c 41 5d 41 5e 41 5f c3 45 84 db 75 50 45 8a 59 01 45 84 db 0f RSP: 0018:ffffc9000159fb78 EFLAGS: 00000056 RAX: 0000000000000001 RBX: 00000000000000a1 RCX: ffffffff815b9761 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f90b490 RBP: ffffc9000159fd48 R08: dffffc0000000000 R09: fffffbfff1f21693 R10: fffffbfff1f21693 R11: 0000000000000000 R12: 1ffffffff1f21692 R13: dffffc0000000001 R14: 0000000000000001 R15: ffff8880134d8978 FS: 00007f60a188f8c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f609eccb000 CR3: 0000000011ff3000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] hlock_class kernel/locking/lockdep.c:198 [inline] lookup_chain_cache_add kernel/locking/lockdep.c:3520 [inline] validate_chain kernel/locking/lockdep.c:3576 [inline] __lock_acquire+0x1351/0x5e90 kernel/locking/lockdep.c:4832 lock_acquire+0x114/0x5e0 kernel/locking/lockdep.c:5442 fs_reclaim_acquire+0x75/0xd0 mm/page_alloc.c:4343 might_alloc include/linux/sched/mm.h:193 [inline] slab_pre_alloc_hook mm/slab.h:493 [inline] slab_alloc_node mm/slub.c:2817 [inline] slab_alloc mm/slub.c:2900 [inline] kmem_cache_alloc+0x36/0x2e0 mm/slub.c:2905 prepare_creds+0x3d/0x5f0 kernel/cred.c:258 access_override_creds fs/open.c:353 [inline] do_faccessat+0x86/0x870 fs/open.c:417 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f60a0b4a9c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007fff05bfdeb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007fff05c00dd0 RCX: 00007f60a0b4a9c7 RDX: 00007f60a15bba00 RSI: 0000000000000000 RDI: 0000564322b899a3 RBP: 00007fff05bfdef0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fff05c00dd0 R15: 00007fff05bfe3e0