------------[ cut here ]------------ WARNING: CPU: 1 PID: 24031 at lib/percpu-refcount.c:111 percpu_ref_exit+0xab/0xd0 lib/percpu-refcount.c:111 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 24031 Comm: syz-executor999 Not tainted 5.6.0-rc2-next-20200221-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+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:175 [inline] fixup_bug arch/x86/kernel/traps.c:170 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:percpu_ref_exit+0xab/0xd0 lib/percpu-refcount.c:111 Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 1d 48 c7 43 08 03 00 00 00 e8 b1 00 d2 fd 5b 41 5c 41 5d 5d c3 e8 a5 00 d2 fd <0f> 0b eb bf 4c 89 ef e8 29 2e 11 fe eb d9 e8 82 2d 11 fe eb a7 4c RSP: 0018:ffffc90003b57bb0 EFLAGS: 00010293 RAX: ffff8880a3b32500 RBX: ffff8880a6e3e210 RCX: ffffffff83a3e392 RDX: 0000000000000000 RSI: ffffffff83a3e3fb RDI: ffff8880a6e3e228 RBP: ffffc90003b57bc8 R08: ffff8880a3b32500 R09: ffffed1014dc7c4a R10: ffffed1014dc7c49 R11: ffff8880a6e3e24f R12: 0000607f51435468 R13: ffff8880a6e3e218 R14: ffff888096c8f000 R15: ffff888096c8f2a8 io_sqe_files_unregister+0x8f/0x2f0 fs/io_uring.c:5417 io_ring_ctx_free fs/io_uring.c:6413 [inline] io_ring_ctx_wait_and_kill+0x4ed/0xa60 fs/io_uring.c:6504 io_uring_release+0x42/0x50 fs/io_uring.c:6512 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xbcb/0x3030 kernel/exit.c:802 do_group_exit+0x135/0x360 kernel/exit.c:900 __do_sys_exit_group kernel/exit.c:911 [inline] __se_sys_exit_group kernel/exit.c:909 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:909 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440068 Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 RSP: 002b:00007fff809b5518 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440068 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004bf890 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds..