INFO: task syz-executor600:6855 blocked for more than 143 seconds. Not tainted 5.8.0-next-20200814-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor600 D28096 6855 6849 0x80000002 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 io_uring_cancel_files fs/io_uring.c:7897 [inline] io_uring_flush+0x740/0xa90 fs/io_uring.c:7914 filp_close+0xb4/0x170 fs/open.c:1276 close_files fs/file.c:401 [inline] put_files_struct fs/file.c:429 [inline] put_files_struct+0x1cc/0x350 fs/file.c:426 exit_files+0x7e/0xa0 fs/file.c:458 do_exit+0xb43/0x29f0 kernel/exit.c:801 do_group_exit+0x125/0x310 kernel/exit.c:903 __do_sys_exit_group kernel/exit.c:914 [inline] __se_sys_exit_group kernel/exit.c:912 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:912 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x43f298 Code: Bad RIP value. RSP: 002b:00007ffeb6d09838 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043f298 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004beaa8 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000000400a29 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d01a0 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1171: #0: ffffffff89c66c40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5825 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1171 Comm: khungtaskd Not tainted 5.8.0-next-20200814-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:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd89/0xf30 kernel/hung_task.c:339 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3896 Comm: systemd-journal Not tainted 5.8.0-next-20200814-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unwind_next_frame+0x17/0x1f90 arch/x86/kernel/unwind_orc.c:424 Code: 0c 24 e8 7c 16 81 00 48 8b 0c 24 e9 72 ff ff ff 0f 1f 00 48 b8 00 00 00 00 00 fc ff df 41 57 49 89 ff 41 56 41 55 41 54 55 53 <48> 81 ec a0 00 00 00 48 c7 44 24 40 b3 8a b5 41 48 8d 5c 24 40 48 RSP: 0018:ffffc900015f78e0 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: ffffffff816366e0 RCX: 0000000000000000 RDX: 1ffff920002bef4e RSI: ffffffff81c3b941 RDI: ffffc900015f7918 RBP: ffffc900015f79a0 R08: ffffffff8b31425a R09: 0000000000000001 R10: 000000000007201e R11: 0000000000000001 R12: ffffc900015f79d0 R13: 0000000000000000 R14: ffff8880930bc280 R15: ffffc900015f7918 FS: 00007f26714f28c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f266e891000 CR3: 000000009320f000 CR4: 00000000001506f0 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 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 putname+0xe1/0x120 fs/namei.c:259 filename_lookup+0x3b1/0x560 fs/namei.c:2376 user_path_at include/linux/namei.h:59 [inline] do_faccessat+0x129/0x820 fs/open.c:423 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f26707ae9c7 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:00007fffe2919f38 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007fffe291ce50 RCX: 00007f26707ae9c7 RDX: 00007f267121fa00 RSI: 0000000000000000 RDI: 00005580040b09a3 RBP: 00007fffe2919f70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fffe291ce50 R15: 00007fffe291a460