INFO: task systemd-udevd:8616 blocked for more than 143 seconds. Not tainted 5.15.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-udevd state:D stack:27160 pid: 8616 ppid: 2970 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4969 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6250 schedule+0xd2/0x260 kernel/sched/core.c:6323 blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178 lo_release+0x160/0x1f0 drivers/block/loop.c:1768 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: 0033:0x7f26619be270 RSP: 002b:00007fff478113a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f26619be270 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f2662878710 R08: 000055568eb005a0 R09: 000055568eb00300 R10: 00007f26628788c0 R11: 0000000000000246 R12: 0000000000000000 R13: 000055568eb00660 R14: 0000000000000003 R15: 000000000000000e Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8bb80fe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 1 lock held by in:imklog/6215: 1 lock held by syz-executor.2/29733: #0: ffff88801acd2918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0x9b/0xb50 block/bdev.c:819 2 locks held by systemd-udevd/8616: #0: ffff88801acd2918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x97/0x9e0 block/bdev.c:914 #1: ffff88801ac62360 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:1748 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline] watchdog+0xc1d/0xf50 kernel/hung_task.c:295 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2952 Comm: systemd-journal Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unwind_next_frame+0x4c/0x1ce0 arch/x86/kernel/unwind_orc.c:418 Code: 40 b3 8a b5 41 48 8d 5c 24 40 48 c7 44 24 48 69 2a 36 8b 48 c1 eb 03 48 c7 44 24 50 a0 3a 34 81 48 8d 14 03 c7 02 f1 f1 f1 f1 42 04 00 f3 f3 f3 48 89 fa 65 48 8b 34 25 28 00 00 00 48 89 b4 RSP: 0018:ffffc9000aca79c0 EFLAGS: 00000a02 RAX: dffffc0000000000 RBX: 1ffff92001594f40 RCX: 0000000000000000 RDX: fffff52001594f40 RSI: ffffffff81bcfe05 RDI: ffffc9000aca7a98 RBP: ffffc9000aca7b20 R08: 0000000000000001 R09: 0000000000000001 R10: fffff52001594f5e R11: 000000000008808a R12: ffffc9000aca7b50 R13: 0000000000000000 R14: ffffc9000aca7a98 R15: ffff88801b5ed600 FS: 00007fee2fe9e8c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fee2d71f008 CR3: 0000000077a35000 CR4: 00000000003506f0 DR0: 00000000000043ce DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x85/0xb0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc mm/slab.c:3323 [inline] kmem_cache_alloc+0x265/0x560 mm/slab.c:3507 prepare_creds+0x3f/0x7b0 kernel/cred.c:260 access_override_creds fs/open.c:351 [inline] do_faccessat+0x3f4/0x850 fs/open.c:415 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: 0033:0x7fee2f1599c7 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:00007ffcbd2e0ca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffcbd2e3cd0 RCX: 00007fee2f1599c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055fde38d69a3 RBP: 00007ffcbd2e0df0 R08: 000055fde38cc3e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000055fde42f68c0 R15: 00007ffcbd2e12e0 ---------------- Code disassembly (best guess): 0: 40 b3 8a mov $0x8a,%bl 3: b5 41 mov $0x41,%ch 5: 48 8d 5c 24 40 lea 0x40(%rsp),%rbx a: 48 c7 44 24 48 69 2a movq $0xffffffff8b362a69,0x48(%rsp) 11: 36 8b 13: 48 c1 eb 03 shr $0x3,%rbx 17: 48 c7 44 24 50 a0 3a movq $0xffffffff81343aa0,0x50(%rsp) 1e: 34 81 20: 48 8d 14 03 lea (%rbx,%rax,1),%rdx 24: c7 02 f1 f1 f1 f1 movl $0xf1f1f1f1,(%rdx) * 2a: c7 42 04 00 f3 f3 f3 movl $0xf3f3f300,0x4(%rdx) <-- trapping instruction 31: 48 89 fa mov %rdi,%rdx 34: 65 48 8b 34 25 28 00 mov %gs:0x28,%rsi 3b: 00 00 3d: 48 rex.W 3e: 89 .byte 0x89 3f: b4 .byte 0xb4