================================ WARNING: inconsistent lock state 6.7.0-rc1-next-20231117-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. syz-executor.2/13183 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff88804dcf9bd8 (&sighand->siglock){?...}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88804dcf9bd8 (&sighand->siglock){?...}-{2:2}, at: class_spinlock_constructor include/linux/spinlock.h:530 [inline] ffff88804dcf9bd8 (&sighand->siglock){?...}-{2:2}, at: ptrace_set_stopped kernel/ptrace.c:391 [inline] ffff88804dcf9bd8 (&sighand->siglock){?...}-{2:2}, at: ptrace_attach+0x401/0x650 kernel/ptrace.c:478 {IN-HARDIRQ-W} state was registered at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 kernel/signal.c:1422 lock_task_sighand include/linux/sched/signal.h:748 [inline] send_sigqueue+0x1d4/0x840 kernel/signal.c:1996 posix_timer_event kernel/time/posix-timers.c:298 [inline] posix_timer_fn+0x181/0x3d0 kernel/time/posix-timers.c:324 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x20c/0xc20 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline] __sysvec_apic_timer_interrupt+0x10c/0x410 arch/x86/kernel/apic/apic.c:1082 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 get_current arch/x86/include/asm/current.h:48 [inline] finish_task_switch.isra.0+0x220/0xcb0 kernel/sched/core.c:5273 context_switch kernel/sched/core.c:5402 [inline] __schedule+0xf1d/0x5c00 kernel/sched/core.c:6726 __schedule_loop kernel/sched/core.c:6801 [inline] schedule+0xe7/0x270 kernel/sched/core.c:6816 do_nanosleep+0x216/0x500 kernel/time/hrtimer.c:2047 hrtimer_nanosleep+0x1ab/0x440 kernel/time/hrtimer.c:2100 common_nsleep+0xa1/0xc0 kernel/time/posix-timers.c:1350 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1396 [inline] __se_sys_clock_nanosleep kernel/time/posix-timers.c:1373 [inline] __x64_sys_clock_nanosleep+0x341/0x490 kernel/time/posix-timers.c:1373 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a irq event stamp: 3833 hardirqs last enabled at (3833): [] irqentry_exit+0x3b/0x80 kernel/entry/common.c:435 hardirqs last disabled at (3832): [] sysvec_apic_timer_interrupt+0xe/0xb0 arch/x86/kernel/apic/apic.c:1076 softirqs last enabled at (1658): [] softirq_handle_end kernel/softirq.c:399 [inline] softirqs last enabled at (1658): [] __do_softirq+0x591/0x8d5 kernel/softirq.c:582 softirqs last disabled at (1641): [] invoke_softirq kernel/softirq.c:427 [inline] softirqs last disabled at (1641): [] __irq_exit_rcu kernel/softirq.c:632 [inline] softirqs last disabled at (1641): [] irq_exit_rcu+0xb5/0x120 kernel/softirq.c:644 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sighand->siglock); lock(&sighand->siglock); *** DEADLOCK *** 2 locks held by syz-executor.2/13183: #0: ffff88801da4e3c8 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: class_mutex_intr_constructor include/linux/mutex.h:225 [inline] #0: ffff88801da4e3c8 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: ptrace_attach+0x1eb/0x650 kernel/ptrace.c:455 #1: ffffffff8cc0a098 (tasklist_lock){++++}-{2:2}, at: class_write_lock_constructor include/linux/spinlock.h:564 [inline] #1: ffffffff8cc0a098 (tasklist_lock){++++}-{2:2}, at: ptrace_attach+0x2c3/0x650 kernel/ptrace.c:464 stack backtrace: CPU: 1 PID: 13183 Comm: syz-executor.2 Not tainted 6.7.0-rc1-next-20231117-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3970 [inline] valid_state kernel/locking/lockdep.c:4012 [inline] mark_lock_irq kernel/locking/lockdep.c:4215 [inline] mark_lock+0x91a/0xc50 kernel/locking/lockdep.c:4677 mark_usage kernel/locking/lockdep.c:4586 [inline] __lock_acquire+0x919/0x3b10 kernel/locking/lockdep.c:5090 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:530 [inline] ptrace_set_stopped kernel/ptrace.c:391 [inline] ptrace_attach+0x401/0x650 kernel/ptrace.c:478 __do_sys_ptrace+0x204/0x230 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a RIP: 0033:0x7f9acba7cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9acc7540c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000065 RAX: ffffffffffffffda RBX: 00007f9acbb9bf80 RCX: 00007f9acba7cae9 RDX: 0000000000000000 RSI: 00000000000004d8 RDI: 0000000000000010 RBP: 00007f9acbac847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f9acbb9bf80 R15: 00007ffdeaf5ffd8