INFO: task syz-executor.4:11329 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:23400 pid:11329 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: 0033:0x7f7db1dbcf57 RSP: 002b:00007ffe620752a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f7db1dbcf57 RDX: 00007ffe6207537c RSI: 000000000000000a RDI: 00007ffe62075370 RBP: 00007ffe62075370 R08: 00000000ffffffff R09: 00007ffe62075140 R10: 0000555555ad5903 R11: 0000000000000246 R12: 00007f7db1e15105 R13: 00007ffe62076430 R14: 0000555555ad5810 R15: 00007ffe62076470 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 4 locks held by kworker/u4:3/90: 1 lock held by in:imklog/6221: #0: ffff8880239ec370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 2 locks held by agetty/6227: #0: ffff88801d36e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252 #1: ffffc90001fbc2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113 2 locks held by syz-executor.4/11329: #0: ffff88801ac4f918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x97/0x9e0 block/bdev.c:914 #1: ffff88801ac4b360 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x7a/0x1070 drivers/block/loop.c:1106 ============================================= NMI backtrace for cpu 1 CPU: 1 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 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:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x7/0x60 kernel/kcov.c:200 Code: 46 00 5d be 03 00 00 00 e9 c6 65 5f 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 8b 05 f9 cb 8a 7e <89> c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 a9 RSP: 0018:ffffc90001b6fc78 EFLAGS: 00000093 RAX: 0000000080000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88807b4457c0 RSI: ffffffff817dea3e RDI: 0000000000000003 RBP: ffffffff81be7965 R08: 0000000000000000 R09: 00000000f08cc7fe R10: ffffffff817dea08 R11: 0000000000000000 R12: ffff888010dd13c0 R13: 0000000000000200 R14: ffffc90001b6fd50 R15: ffff8880a6f7b300 FS: 00007fb7c81b28c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7c5085000 CR3: 000000002391a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000006 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] static_key_false include/linux/jump_label.h:212 [inline] trace_irq_enable_rcuidle include/trace/events/preemptirq.h:40 [inline] trace_hardirqs_on+0x7a/0x1c0 kernel/trace/trace_preemptirq.c:44 kasan_quarantine_put+0xf5/0x210 mm/kasan/quarantine.c:220 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 slab_free mm/slub.c:3513 [inline] kmem_cache_free+0x92/0x5e0 mm/slub.c:3529 putname fs/namei.c:270 [inline] putname+0xfe/0x140 fs/namei.c:256 do_sys_openat2+0x153/0x4d0 fs/open.c:1221 do_sys_open fs/open.c:1228 [inline] __do_sys_open fs/open.c:1236 [inline] __se_sys_open fs/open.c:1232 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1232 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: 0033:0x7fb7c7741840 Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24 RSP: 002b:00007ffcc6d9ca88 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ffcc6d9cd90 RCX: 00007fb7c7741840 RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 0000559fe0ef1a50 RBP: 000000000000000d R08: 00000000000001c0 R09: 00000000ffffffff R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000559fe0ee5040 R14: 00007ffcc6d9cd50 R15: 0000559fe0ef1870 ---------------- Code disassembly (best guess): 0: 46 00 5d be rex.RX add %r11b,-0x42(%rbp) 4: 03 00 add (%rax),%eax 6: 00 00 add %al,(%rax) 8: e9 c6 65 5f 02 jmpq 0x25f65d3 d: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 13: 48 8b be b0 01 00 00 mov 0x1b0(%rsi),%rdi 1a: e8 b4 ff ff ff callq 0xffffffd3 1f: 31 c0 xor %eax,%eax 21: c3 retq 22: 90 nop 23: 65 8b 05 f9 cb 8a 7e mov %gs:0x7e8acbf9(%rip),%eax # 0x7e8acc23 * 2a: 89 c1 mov %eax,%ecx <-- trapping instruction 2c: 48 8b 34 24 mov (%rsp),%rsi 30: 81 e1 00 01 00 00 and $0x100,%ecx 36: 65 48 8b 14 25 40 70 mov %gs:0x27040,%rdx 3d: 02 00 3f: a9 .byte 0xa9