Hello, When using Healer to fuzz the latest Linux kernel, the following crash was triggered. HEAD commit: ff1ffd71d5f0 Merge tag 'hyperv-fixes-signed-20210915 git tree: upstream console output: https://drive.google.com/file/d/1uDfJnwful_fOzqNVRIHEf7PqIsqZDcvG/view?usp=sharing kernel config: https://drive.google.com/file/d/1zXpDhs-IdE7tX17B7MhaYP0VGUfP6m9B/view?usp=sharing Sorry, I don't have a reproducer for this crash, hope the symbolized report can help. If you fix this issue, please add the following tag to the commit: Reported-by: Hao Sun <sunhao.th@xxxxxxxxx> INFO: task syz-executor:15349 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:28400 pid:15349 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 blk_mq_freeze_queue_wait+0x114/0x160 block/blk-mq.c:151 nbd_add_socket+0x102/0x7c0 drivers/block/nbd.c:1050 __nbd_ioctl drivers/block/nbd.c:1405 [inline] nbd_ioctl+0x391/0x9c0 drivers/block/nbd.c:1462 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db27fc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c0a0 RCX: 00000000004739cd RDX: 0000000000000006 RSI: 000000000000ab00 RDI: 0000000000000008 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c0a0 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db27fdc0 INFO: task syz-executor:15350 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:28400 pid:15350 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 nbd_ioctl+0x14f/0x9c0 drivers/block/nbd.c:1455 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db25ec58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c158 RCX: 00000000004739cd RDX: 0000000000000006 RSI: 000000000000ab00 RDI: 0000000000000004 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c158 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db25edc0 INFO: task syz-executor:15351 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:29552 pid:15351 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 nbd_ioctl+0x14f/0x9c0 drivers/block/nbd.c:1455 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db23dc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c210 RCX: 00000000004739cd RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000009 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c210 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db23ddc0 INFO: task syz-executor:15352 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:28400 pid:15352 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 nbd_ioctl+0x14f/0x9c0 drivers/block/nbd.c:1455 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db21cc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c2c8 RCX: 00000000004739cd RDX: 00000000000003ff RSI: 000000000000ab0a RDI: 0000000000000003 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c2c8 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db21cdc0 INFO: task syz-executor:15353 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:28400 pid:15353 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 nbd_ioctl+0x14f/0x9c0 drivers/block/nbd.c:1455 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db1fbc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c380 RCX: 00000000004739cd RDX: 0000000000000005 RSI: 000000000000ab00 RDI: 0000000000000007 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c380 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db1fbdc0 INFO: task syz-executor:15354 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:28400 pid:15354 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 nbd_ioctl+0x14f/0x9c0 drivers/block/nbd.c:1455 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db1dac58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c438 RCX: 00000000004739cd RDX: 0000000000000005 RSI: 000000000000ab00 RDI: 0000000000000004 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c438 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db1dadc0 INFO: task syz-executor:15355 blocked for more than 143 seconds. Not tainted 5.15.0-rc1+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:29336 pid:15355 ppid: 14720 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 nbd_ioctl+0x14f/0x9c0 drivers/block/nbd.c:1455 blkdev_ioctl+0x2a4/0x720 block/ioctl.c:589 block_ioctl+0xfa/0x140 block/fops.c:477 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: 0033:0x4739cd RSP: 002b:00007fb9db1b9c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000059c4f0 RCX: 00000000004739cd RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000008 RBP: 00000000004ebd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c4f0 R13: 00007ffd4c2267df R14: 00007ffd4c226980 R15: 00007fb9db1b9dc0 INFO: lockdep is turned off. NMI backtrace for cpu 1 CPU: 1 PID: 39 Comm: khungtaskd Not tainted 5.15.0-rc1+ #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 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+0x1e1/0x220 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+0xcc8/0x1010 kernel/hung_task.c:295 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0,2-3: NMI backtrace for cpu 3 CPU: 3 PID: 3026 Comm: systemd-journal Not tainted 5.15.0-rc1+ #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0033:0x5654ffc2727b Code: e4 48 83 bb 98 00 00 00 00 74 24 48 8b 55 d8 64 48 33 14 25 28 00 00 00 44 89 e0 0f 85 ec 03 00 00 48 8d 65 e0 5b 41 5c 41 5d <41> 5e 5d c3 90 83 bb 24 02 00 00 03 74 d3 4c 8b ab f0 00 00 00 4d RSP: 002b:00007ffd23734c48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007ffd23737b30 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffd23737bd0 RBP: 00007ffd23734c50 R08: 00005654ffc273e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000009 R14: 00005655006498a0 R15: 00007ffd23735140 FS: 00007fdcd6b8d8c0 GS: 0000000000000000 NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:716 NMI backtrace for cpu 2 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 2 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 2 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:716
