INFO: task syz-executor.1:6540 blocked for more than 143 seconds. Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:23792 pid: 6540 ppid: 1 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4987 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6268 schedule+0xd2/0x260 kernel/sched/core.c:6341 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6400 __mutex_lock_common kernel/locking/mutex.c:680 [inline] __mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:740 blkdev_get_by_dev.part.0+0x9b/0xb50 block/bdev.c:819 blkdev_get_by_dev+0x6b/0x80 block/bdev.c:859 blkdev_open+0x154/0x2e0 block/fops.c:501 do_dentry_open+0x4c8/0x1250 fs/open.c:822 do_open fs/namei.c:3426 [inline] path_openat+0x1cad/0x2750 fs/namei.c:3559 do_filp_open+0x1aa/0x400 fs/namei.c:3586 do_sys_openat2+0x16d/0x4d0 fs/open.c:1212 do_sys_open fs/open.c:1228 [inline] __do_sys_openat fs/open.c:1244 [inline] __se_sys_openat fs/open.c:1239 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1239 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7ffb519cea04 RSP: 002b:00007fff5deed840 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fff5deed940 RCX: 00007ffb519cea04 RDX: 0000000000000002 RSI: 00007fff5deed980 RDI: 00000000ffffff9c RBP: 00007fff5deed980 R08: 0000000000000000 R09: 00007fff5deed750 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000014 R15: 00007fff5deed980 INFO: task systemd-udevd:16347 blocked for more than 143 seconds. Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-udevd state:D stack:26144 pid:16347 ppid: 2970 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4987 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6268 schedule+0xd2/0x260 kernel/sched/core.c:6341 blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178 __loop_clr_fd+0x1ae/0x1070 drivers/block/loop.c:1122 lo_release+0x1ac/0x1f0 drivers/block/loop.c:1761 blkdev_put_whole block/bdev.c:694 [inline] blkdev_put+0x2fb/0x9e0 block/bdev.c:956 blkdev_close+0x6a/0x80 block/fops.c:515 __fput+0x286/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2207b88270 RSP: 002b:00007ffd5202d518 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f2207b88270 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f2208a42710 R08: 00005592976290d0 R09: 0000559297628e00 R10: 00007f2208a428c0 R11: 0000000000000246 R12: 0000000000000000 R13: 00005592976295c0 R14: 0000000000000003 R15: 000000000000000e Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8bb83ba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 2 locks held by kworker/u4:4/279: 1 lock held by in:imklog/6225: #0: ffff8880221bc370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 1 lock held by syz-executor.1/6540: #0: ffff88801ab62118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0x9b/0xb50 block/bdev.c:819 3 locks held by kworker/u4:15/13761: 2 locks held by systemd-udevd/16347: #0: ffff88801ab62118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x97/0x9e0 block/bdev.c:914 #1: ffff88801ab0db60 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x7a/0x1070 drivers/block/loop.c:1106 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline] watchdog+0xcb7/0xed0 kernel/hung_task.c:339 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2969 Comm: systemd-journal Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_preemption_disabled+0x3e/0x170 lib/smp_processor_id.c:56 Code: 44 8b 25 0d d0 c0 76 65 8b 1d 7e 2a c1 76 81 e3 ff ff ff 7f 31 ff 89 de 0f 1f 44 00 00 85 db 74 11 0f 1f 44 00 00 44 89 e0 5b <5d> 41 5c 41 5d 41 5e c3 0f 1f 44 00 00 9c 5b 81 e3 00 02 00 00 31 RSP: 0018:ffffc9000b4b7828 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffffff8a04b6a0 R08: 0000000000000000 R09: ffffffff8d90e7d7 R10: fffffbfff1b21cfa R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff89ac1080 R14: 00000000ffffffff R15: ffff88807ab4a7a8 FS: 00007f4dcb2d88c0(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4dc8810000 CR3: 00000000190c0000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:438 [inline] lock_is_held_type+0xd7/0x140 kernel/locking/lockdep.c:5681 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x442/0x510 kernel/locking/lockdep.c:5608 seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline] __follow_mount_rcu fs/namei.c:1455 [inline] handle_mounts fs/namei.c:1486 [inline] step_into+0x1429/0x1c80 fs/namei.c:1800 walk_component+0x171/0x6a0 fs/namei.c:1976 link_path_walk.part.0+0x757/0xd00 fs/namei.c:2297 link_path_walk fs/namei.c:2221 [inline] path_lookupat+0xc8/0x860 fs/namei.c:2448 filename_lookup+0x1c6/0x590 fs/namei.c:2478 user_path_at_empty+0x42/0x60 fs/namei.c:2801 user_path_at include/linux/namei.h:57 [inline] do_faccessat+0x127/0x850 fs/open.c:421 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f4dca5939c7 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:00007ffd305c73d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffd305ca2f0 RCX: 00007f4dca5939c7 RDX: 00007f4dcb004a00 RSI: 0000000000000000 RDI: 0000564188ca49a3 RBP: 00007ffd305c7410 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffd305ca2f0 R15: 00007ffd305c7900 ---------------- Code disassembly (best guess): 0: 44 8b 25 0d d0 c0 76 mov 0x76c0d00d(%rip),%r12d # 0x76c0d014 7: 65 8b 1d 7e 2a c1 76 mov %gs:0x76c12a7e(%rip),%ebx # 0x76c12a8c e: 81 e3 ff ff ff 7f and $0x7fffffff,%ebx 14: 31 ff xor %edi,%edi 16: 89 de mov %ebx,%esi 18: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 1d: 85 db test %ebx,%ebx 1f: 74 11 je 0x32 21: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 26: 44 89 e0 mov %r12d,%eax 29: 5b pop %rbx * 2a: 5d pop %rbp <-- trapping instruction 2b: 41 5c pop %r12 2d: 41 5d pop %r13 2f: 41 5e pop %r14 31: c3 retq 32: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 37: 9c pushfq 38: 5b pop %rbx 39: 81 e3 00 02 00 00 and $0x200,%ebx 3f: 31 .byte 0x31