INFO: task syz-executor.5:10688 blocked for more than 143 seconds. Not tainted 5.16.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.5 state:D stack:29520 pid:10688 ppid: 8466 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178 del_gendisk+0x598/0x860 block/genhd.c:623 loop_remove+0x39/0xf0 drivers/block/loop.c:2080 loop_control_remove drivers/block/loop.c:2137 [inline] loop_control_ioctl+0x445/0x4a0 drivers/block/loop.c:2175 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 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: 0033:0x7ff1a0f1cae9 RSP: 002b:00007ff19e471188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ff1a1030020 RCX: 00007ff1a0f1cae9 RDX: 0000000000000006 RSI: 0000000000004c81 RDI: 0000000000000005 RBP: 00007ff1a0f76f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdf809e0af R14: 00007ff19e471300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8bb80ee0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 1 lock held by in:imklog/6220: #0: ffff888079900630 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.16.0-rc1-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2970 Comm: systemd-journal Not tainted 5.16.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__kasan_check_write+0x4/0x10 mm/kasan/shadow.c:37 Code: 5d 41 5c 41 5d c3 c3 e9 ca 8f 52 07 cc cc cc cc cc cc cc cc cc cc 48 8b 0c 24 89 f6 31 d2 e9 f3 f9 ff ff 0f 1f 00 48 8b 0c 24 <89> f6 ba 01 00 00 00 e9 e0 f9 ff ff 55 53 48 8b 07 48 89 fb 48 85 RSP: 0018:ffffc9000b58fca8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff8ba3e760 RCX: ffffffff83dad5a1 RDX: ffff888018bc4100 RSI: 0000000000000004 RDI: ffffffff8ba3e760 RBP: 00000000000001b2 R08: 00000000000001b2 R09: ffffffff8ba3e763 R10: ffffffff83dad586 R11: 0000000000000000 R12: 00000000000001b1 R13: 1ffff920016b1f97 R14: ffffc9000b58fcd8 R15: 0000000000000000 FS: 00007f40ddb858c0(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f40daaac000 CR3: 0000000018b38000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_try_cmpxchg_release include/linux/atomic/atomic-instrumented.h:519 [inline] refcount_dec_not_one+0x101/0x1e0 lib/refcount.c:91 refcount_dec_and_lock_irqsave+0x22/0x1b0 lib/refcount.c:175 free_uid+0x7e/0x1f0 kernel/user.c:185 put_cred_rcu+0x245/0x520 kernel/cred.c:122 __put_cred+0x1de/0x250 kernel/cred.c:151 put_cred include/linux/cred.h:288 [inline] put_cred include/linux/cred.h:281 [inline] revert_creds+0x1a8/0x1f0 kernel/cred.c:608 do_faccessat+0x2e7/0x850 fs/open.c:462 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: 0033:0x7f40dce409c7 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:00007fff902cf338 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007fff902d2250 RCX: 00007f40dce409c7 RDX: 00007f40dd8b1a00 RSI: 0000000000000000 RDI: 0000559211aba9a3 RBP: 00007fff902cf370 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fff902d2250 R15: 00007fff902cf860 ---------------- Code disassembly (best guess): 0: 5d pop %rbp 1: 41 5c pop %r12 3: 41 5d pop %r13 5: c3 retq 6: c3 retq 7: e9 ca 8f 52 07 jmpq 0x7528fd6 c: cc int3 d: cc int3 e: cc int3 f: cc int3 10: cc int3 11: cc int3 12: cc int3 13: cc int3 14: cc int3 15: cc int3 16: 48 8b 0c 24 mov (%rsp),%rcx 1a: 89 f6 mov %esi,%esi 1c: 31 d2 xor %edx,%edx 1e: e9 f3 f9 ff ff jmpq 0xfffffa16 23: 0f 1f 00 nopl (%rax) 26: 48 8b 0c 24 mov (%rsp),%rcx * 2a: 89 f6 mov %esi,%esi <-- trapping instruction 2c: ba 01 00 00 00 mov $0x1,%edx 31: e9 e0 f9 ff ff jmpq 0xfffffa16 36: 55 push %rbp 37: 53 push %rbx 38: 48 8b 07 mov (%rdi),%rax 3b: 48 89 fb mov %rdi,%rbx 3e: 48 rex.W 3f: 85 .byte 0x85