INFO: task syz-executor.4:9231 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.4 state:D stack:23832 pid: 9231 ppid: 1 flags:0x00004004 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 deactivate_locked_super+0x94/0x160 fs/super.c:335 deactivate_super+0xad/0xd0 fs/super.c:366 cleanup_mnt+0x3a2/0x540 fs/namespace.c:1137 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: 0033:0x7f2865385f57 RSP: 002b:00007fff446fcbf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f2865385f57 RDX: 00007fff446fccca RSI: 000000000000000a RDI: 00007fff446fccc0 RBP: 00007fff446fccc0 R08: 00000000ffffffff R09: 00007fff446fca90 R10: 00005555562a9903 R11: 0000000000000246 R12: 00007f28653de105 R13: 00007fff446fdd80 R14: 00005555562a9810 R15: 00007fff446fddc0 Showing all locks held in the system: 1 lock held by khungtaskd/26: #0: ffffffff8bb83ba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 1 lock held by in:imklog/6257: #0: ffff888073062d70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 2 locks held by agetty/6459: #0: ffff888019834098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252 #1: ffffc900029fc2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113 2 locks held by syz-executor.4/9231: #0: ffff888019e69118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x97/0x9e0 block/bdev.c:914 #1: ffff888019d9cb60 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x7a/0x1070 drivers/block/loop.c:1106 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 26 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2962 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:stack_trace_consume_entry+0xd5/0x160 kernel/stacktrace.c:93 Code: 0f 85 92 00 00 00 8d 45 01 89 43 10 48 8b 03 48 8d 2c e8 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 80 3c 02 00 75 5c <48> 89 75 00 8b 43 08 39 43 10 0f 92 c0 48 83 c4 08 5b 5d c3 83 e8 RSP: 0018:ffffc90001f6fa80 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffc90001f6fb58 RCX: 0000000000000000 RDX: 1ffff920003edf7e RSI: ffffffff8940fbb5 RDI: ffffc90001f6fb64 RBP: ffffc90001f6fbf0 R08: ffffffff8e187ac2 R09: 0000000000000001 R10: fffff520003edf5f R11: 000000000008808a R12: ffffc90001f6fb58 R13: 0000000000000000 R14: ffff88807aef3a80 R15: 0000000000000cc0 FS: 00007fc39dc0c8c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc39970a000 CR3: 000000001bf4b000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x6d/0xe0 arch/x86/kernel/stacktrace.c:27 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+0x90/0xc0 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_node mm/slub.c:3234 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247 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: 0033:0x7fc39cec79c7 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:00007ffc6d10d268 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffc6d110290 RCX: 00007fc39cec79c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055b8f80699a3 RBP: 00007ffc6d10d3b0 R08: 000055b8f805f3e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000055b8f9d0a8a0 R15: 00007ffc6d10d8a0 ---------------- Code disassembly (best guess): 0: 0f 85 92 00 00 00 jne 0x98 6: 8d 45 01 lea 0x1(%rbp),%eax 9: 89 43 10 mov %eax,0x10(%rbx) c: 48 8b 03 mov (%rbx),%rax f: 48 8d 2c e8 lea (%rax,%rbp,8),%rbp 13: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1a: fc ff df 1d: 48 89 ea mov %rbp,%rdx 20: 48 c1 ea 03 shr $0x3,%rdx 24: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 28: 75 5c jne 0x86 * 2a: 48 89 75 00 mov %rsi,0x0(%rbp) <-- trapping instruction 2e: 8b 43 08 mov 0x8(%rbx),%eax 31: 39 43 10 cmp %eax,0x10(%rbx) 34: 0f 92 c0 setb %al 37: 48 83 c4 08 add $0x8,%rsp 3b: 5b pop %rbx 3c: 5d pop %rbp 3d: c3 retq 3e: 83 .byte 0x83 3f: e8 .byte 0xe8