INFO: task syz-executor.3:25851 blocked for more than 143 seconds. Not tainted 5.8.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28440 25851 7083 0x00004004 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1873 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x163/0x260 kernel/sched/completion.c:138 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2832 nbd_start_device_ioctl drivers/block/nbd.c:1327 [inline] __nbd_ioctl drivers/block/nbd.c:1402 [inline] nbd_ioctl+0x7ac/0xb77 drivers/block/nbd.c:1442 __blkdev_driver_ioctl block/ioctl.c:224 [inline] blkdev_ioctl+0x255/0x6c0 block/ioctl.c:620 block_ioctl+0xf9/0x140 fs/block_dev.c:1988 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007f63f3086c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000010ac0 RCX: 000000000045c1d9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000078bf38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007fff76891b9f R14: 00007f63f30879c0 R15: 000000000078bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1150: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 2 locks held by kworker/u5:1/12161: #0: ffff8880945f1138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880945f1138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880945f1138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880945f1138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880945f1138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880945f1138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90003f97da8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1150 Comm: khungtaskd Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3884 Comm: systemd-journal Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:156 [inline] RIP: 0010:unwind_next_frame+0x20f/0x1f90 arch/x86/kernel/unwind_orc.c:446 Code: b8 02 00 00 48 81 f9 83 1c 20 88 0f 83 ab 02 00 00 44 8b 15 83 b4 4e 08 48 89 ce 48 81 ee 00 00 00 81 48 c1 ee 08 41 8d 52 ff <39> d6 0f 83 54 12 00 00 48 ba 00 00 00 00 00 fc ff df 41 89 f0 4a RSP: 0018:ffffc900016279e8 EFLAGS: 00000003 RAX: 0000000000000000 RBX: 1ffff920002c4f45 RCX: ffffffff81b2d38e RDX: 000000000007201d RSI: 000000000000b2d3 RDI: ffff8880930b17f8 RBP: 0000000000000001 R08: ffffffff89b4f920 R09: 0000000000000001 R10: 000000000007201e R11: 0000000000000001 R12: ffffc90001627b08 R13: ffffc90001627af5 R14: ffffc90001627b10 R15: ffffc90001627ac0 FS: 00007fdec767b8c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdec4c3a000 CR3: 00000000934f2000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kmem_cache_free+0x7f/0x310 mm/slab.c:3694 __put_cred+0x1de/0x250 kernel/cred.c:148 put_cred include/linux/cred.h:287 [inline] put_cred include/linux/cred.h:280 [inline] revert_creds+0x1a8/0x1f0 kernel/cred.c:598 do_faccessat+0x2ca/0x820 fs/open.c:464 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fdec69379c7 Code: Bad RIP value. RSP: 002b:00007ffcae6c0c08 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffcae6c3b20 RCX: 00007fdec69379c7 RDX: 00007fdec73a8a00 RSI: 0000000000000000 RDI: 0000564da9b119a3 RBP: 00007ffcae6c0c40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffcae6c3b20 R15: 00007ffcae6c1130