============================================ WARNING: possible recursive locking detected 6.4.0-rc6-next-20230616-syzkaller #0 Not tainted -------------------------------------------- syz-executor196/6178 is trying to acquire lock: ffff88801eccb640 (&new_timer->it_lock){-.-.}-{2:2}, at: itimer_delete kernel/time/posix-timers.c:1049 [inline] ffff88801eccb640 (&new_timer->it_lock){-.-.}-{2:2}, at: exit_itimers+0x2ac/0x540 kernel/time/posix-timers.c:1109 but task is already holding lock: ffff88801eccb640 (&new_timer->it_lock){-.-.}-{2:2}, at: __lock_timer+0x1cc/0x4d0 kernel/time/posix-timers.c:595 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&new_timer->it_lock); lock(&new_timer->it_lock); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz-executor196/6178: #0: ffff88801eccb640 (&new_timer->it_lock){-.-.}-{2:2}, at: __lock_timer+0x1cc/0x4d0 kernel/time/posix-timers.c:595 stack backtrace: CPU: 1 PID: 6178 Comm: syz-executor196 Not tainted 6.4.0-rc6-next-20230616-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3070 [inline] validate_chain kernel/locking/lockdep.c:3863 [inline] __lock_acquire+0x2a33/0x5e20 kernel/locking/lockdep.c:5144 lock_acquire.part.0+0x11c/0x370 kernel/locking/lockdep.c:5761 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 itimer_delete kernel/time/posix-timers.c:1049 [inline] exit_itimers+0x2ac/0x540 kernel/time/posix-timers.c:1109 do_exit+0x630/0x2a30 kernel/exit.c:848 do_group_exit+0xd4/0x2a0 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1033 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f5dc8cc4dd9 Code: 00 49 c7 c0 b8 ff ff ff be e7 00 00 00 ba 3c 00 00 00 eb 12 0f 1f 44 00 00 89 d0 0f 05 48 3d 00 f0 ff ff 77 1c f4 89 f0 0f 05 <48> 3d 00 f0 ff ff 76 e7 f7 d8 64 41 89 00 eb df 0f 1f 80 00 00 00 RSP: 002b:00007ffe0c959208 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f5dc8d4f210 RCX: 00007f5dc8cc4dd9 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffb8 R09: 00007f5dc8d151cf R10: 00007ffe0c959290 R11: 0000000000000246 R12: 00007f5dc8d4f210 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001