================================ WARNING: inconsistent lock state 5.10.0-rc4-next-20201123-syzkaller #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. syz-fuzzer/8512 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff8881442e36a8 (&file_data->lock){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff8881442e36a8 (&file_data->lock){+.?.}-{2:2}, at: io_file_data_ref_zero+0x75/0x480 fs/io_uring.c:7598 {SOFTIRQ-ON-W} state was registered at: lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] io_sqe_files_register fs/io_uring.c:7733 [inline] __io_uring_register fs/io_uring.c:9823 [inline] __do_sys_io_uring_register+0x33ca/0x40d0 fs/io_uring.c:9913 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 irq event stamp: 185876 hardirqs last enabled at (185876): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] hardirqs last enabled at (185876): [] _raw_spin_unlock_irqrestore+0x42/0x50 kernel/locking/spinlock.c:191 hardirqs last disabled at (185875): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (185875): [] _raw_spin_lock_irqsave+0x4e/0x50 kernel/locking/spinlock.c:159 softirqs last enabled at (185680): [] asm_call_irq_on_stack+0xf/0x20 softirqs last disabled at (185829): [] asm_call_irq_on_stack+0xf/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&file_data->lock); lock(&file_data->lock); *** DEADLOCK *** 2 locks held by syz-fuzzer/8512: #0: ffffffff8b339d40 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2493 [inline] #0: ffffffff8b339d40 (rcu_callback){....}-{0:0}, at: rcu_core+0x698/0xfc0 kernel/rcu/tree.c:2739 #1: ffffffff8b339e60 (rcu_read_lock){....}-{1:2}, at: percpu_ref_put_many.constprop.0+0x0/0x250 net/netfilter/xt_cgroup.c:62 stack backtrace: CPU: 0 PID: 8512 Comm: syz-fuzzer Not tainted 5.10.0-rc4-next-20201123-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 print_usage_bug kernel/locking/lockdep.c:3740 [inline] valid_state kernel/locking/lockdep.c:3751 [inline] mark_lock_irq kernel/locking/lockdep.c:3954 [inline] mark_lock.cold+0x31/0x73 kernel/locking/lockdep.c:4411 mark_usage kernel/locking/lockdep.c:4306 [inline] __lock_acquire+0x11a5/0x5500 kernel/locking/lockdep.c:4786 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] io_file_data_ref_zero+0x75/0x480 fs/io_uring.c:7598 percpu_ref_put_many.constprop.0+0x217/0x250 include/linux/percpu-refcount.h:322 rcu_do_batch kernel/rcu/tree.c:2504 [inline] rcu_core+0x70c/0xfc0 kernel/rcu/tree.c:2739 __do_softirq+0x2a0/0x9f6 kernel/softirq.c:298 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x132/0x200 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628 RIP: 0033:0x410a10 Code: 46 0f b6 14 0b 41 80 fa 01 0f 87 5b 01 00 00 48 85 c9 49 89 db 48 0f 45 d9 4d 89 cc 4d 0f 45 c8 45 84 d2 75 be 48 83 7e 18 00 <0f> 85 a7 00 00 00 48 8b 3e 48 ff c7 0f b6 4e 09 48 83 ff 08 7e 77 RSP: 002b:000000c00031db40 EFLAGS: 00000206 RAX: 9a472e9e02bc8652 RBX: 000000c000bd4bf0 RCX: 0000000000000000 RDX: 0000000000943b20 RSI: 000000c0008db230 RDI: 0000000000000038 RBP: 000000c00031db70 R08: 0000000000000000 R09: 0000000000000004 R10: 0000000000000000 R11: 000000c000bd4bf0 R12: 0000000000000004 R13: 0000000000000001 R14: 0000000000000003 R15: 0000000000000004