Hello, syzbot found the following issue on: HEAD commit: 06a81c1c Merge tag 'arm64-fixes' of git://git.kernel.org/p.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13fbac1c900000 kernel config: https://syzkaller.appspot.com/x/.config?x=bf68a13f867fd1b4 dashboard link: https://syzkaller.appspot.com/bug?extid=d4586d3028284ff8a0be compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1362024e900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1672fd34900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d4586d3028284ff8a0be@xxxxxxxxxxxxxxxxxxxxxxxxx ============================================ WARNING: possible recursive locking detected 5.8.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor880/6847 is trying to acquire lock: ffff8880a19214d8 (&ctx->completion_lock){....}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:379 [inline] ffff8880a19214d8 (&ctx->completion_lock){....}-{2:2}, at: io_queue_linked_timeout+0x4c/0x200 fs/io_uring.c:5928 but task is already holding lock: ffff8880a19214d8 (&ctx->completion_lock){....}-{2:2}, at: io_cqring_overflow_flush+0x814/0xaa0 fs/io_uring.c:1333 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&ctx->completion_lock); lock(&ctx->completion_lock); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz-executor880/6847: #0: ffff8880a19214d8 (&ctx->completion_lock){....}-{2:2}, at: io_cqring_overflow_flush+0x814/0xaa0 fs/io_uring.c:1333 stack backtrace: CPU: 1 PID: 6847 Comm: syz-executor880 Not tainted 5.8.0-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 print_deadlock_bug kernel/locking/lockdep.c:2391 [inline] check_deadlock kernel/locking/lockdep.c:2432 [inline] validate_chain kernel/locking/lockdep.c:3202 [inline] __lock_acquire.cold+0x115/0x396 kernel/locking/lockdep.c:4426 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5005 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x5b/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:379 [inline] io_queue_linked_timeout+0x4c/0x200 fs/io_uring.c:5928 __io_queue_async_work+0x1f8/0x4c0 fs/io_uring.c:1192 __io_queue_deferred fs/io_uring.c:1237 [inline] io_commit_cqring+0x456/0x7a0 fs/io_uring.c:1265 io_cqring_overflow_flush+0x5b8/0xaa0 fs/io_uring.c:1359 io_ring_ctx_wait_and_kill+0x30e/0x600 fs/io_uring.c:7808 io_uring_release+0x3e/0x50 fs/io_uring.c:7829 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:135 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb7d/0x29f0 kernel/exit.c:806 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: 0033:0x43f598 Code: Bad RIP value. RSP: 002b:00007ffd3a4fbaa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043f598 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004beda8 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d11a0 R14: 0000000000000000 R15: 0000000000000000 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
