syzbot

========================================================
WARNING: possible irq lock inversion dependency detected
6.7.0-rc1-next-20231117-syzkaller #0 Not tainted
--------------------------------------------------------
syz-executor.3/7674 just changed the state of lock:
ffff88802796e038 (&new_timer->it_lock){-...}-{2:2}, at: posix_timer_fn+0x2d/0x3d0 kernel/time/posix-timers.c:318
but this lock took another, HARDIRQ-unsafe lock in the past:
 (&sighand->siglock){+.+.}-{2:2}


and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sighand->siglock);
                               local_irq_disable();
                               lock(&new_timer->it_lock);
                               lock(&sighand->siglock);
  <Interrupt>
    lock(&new_timer->it_lock);

 *** DEADLOCK ***

no locks held by syz-executor.3/7674.

the shortest dependencies between 2nd lock and 1st lock:
 -> (&sighand->siglock){+.+.}-{2:2} {
    HARDIRQ-ON-W at:
                      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
    SOFTIRQ-ON-W at:
                      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
    INITIAL USE at:
                     lock_acquire kernel/locking/lockdep.c:5753 [inline]
                     lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718
                     __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
                     _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170
                     spin_lock_irq include/linux/spinlock.h:376 [inline]
                     calculate_sigpending+0x44/0xa0 kernel/signal.c:197
                     ret_from_fork+0x23/0x80 arch/x86/kernel/process.c:143
                     ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
  }
  ... key      at: [<ffffffff90b4af80>] __key.341+0x0/0x40
  ... acquired at:
   __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]
   __do_sys_timer_delete kernel/time/posix-timers.c:1023 [inline]
   __se_sys_timer_delete kernel/time/posix-timers.c:1006 [inline]
   __x64_sys_timer_delete+0x16a/0x3e0 kernel/time/posix-timers.c:1006
   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

-> (&new_timer->it_lock){-...}-{2:2} {
   IN-HARDIRQ-W 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
                    posix_timer_fn+0x2d/0x3d0 kernel/time/posix-timers.c:318
                    __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
                    __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
                    _raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194
                    spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
                    unlock_timer kernel/time/posix-timers.c:128 [inline]
                    do_timer_settime+0x260/0x2f0 kernel/time/posix-timers.c:934
                    __do_sys_timer_settime kernel/time/posix-timers.c:954 [inline]
                    __se_sys_timer_settime kernel/time/posix-timers.c:940 [inline]
                    __x64_sys_timer_settime+0x266/0x2c0 kernel/time/posix-timers.c:940
                    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
   INITIAL USE 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_timer+0x20d/0x4c0 kernel/time/posix-timers.c:595
                   do_timer_settime+0x197/0x2f0 kernel/time/posix-timers.c:916
                   __do_sys_timer_settime kernel/time/posix-timers.c:954 [inline]
                   __se_sys_timer_settime kernel/time/posix-timers.c:940 [inline]
                   __x64_sys_timer_settime+0x266/0x2c0 kernel/time/posix-timers.c:940
                   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
 }
 ... key      at: [<ffffffff9280bea0>] __key.0+0x0/0x40
 ... acquired at:
   mark_usage kernel/locking/lockdep.c:4563 [inline]
   __lock_acquire+0x1347/0x3b10 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_irqsave include/linux/spinlock_api_smp.h:110 [inline]
   _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
   posix_timer_fn+0x2d/0x3d0 kernel/time/posix-timers.c:318
   __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
   __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
   _raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194
   spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
   unlock_timer kernel/time/posix-timers.c:128 [inline]
   do_timer_settime+0x260/0x2f0 kernel/time/posix-timers.c:934
   __do_sys_timer_settime kernel/time/posix-timers.c:954 [inline]
   __se_sys_timer_settime kernel/time/posix-timers.c:940 [inline]
   __x64_sys_timer_settime+0x266/0x2c0 kernel/time/posix-timers.c:940
   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


stack backtrace:
CPU: 1 PID: 7674 Comm: syz-executor.3 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:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_irq_inversion_bug.part.0+0x3e1/0x590 kernel/locking/lockdep.c:4079
 print_irq_inversion_bug kernel/locking/lockdep.c:4032 [inline]
 check_usage_forwards kernel/locking/lockdep.c:4110 [inline]
 mark_lock_irq kernel/locking/lockdep.c:4242 [inline]
 mark_lock+0x570/0xc50 kernel/locking/lockdep.c:4677
 mark_usage kernel/locking/lockdep.c:4563 [inline]
 __lock_acquire+0x1347/0x3b10 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_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
 posix_timer_fn+0x2d/0x3d0 kernel/time/posix-timers.c:318
 __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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 16 c8 e3 f6 48 89 df e8 ce 3f e4 f6 f7 c5 00 02 00 00 75 1f 9c 58 f6 c4 02 75 2f <bf> 01 00 00 00 e8 85 ed d5 f6 65 8b 05 a6 18 7f 75 85 c0 74 12 5b
RSP: 0018:ffffc900164d7d70 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88802796e020 RCX: 1ffffffff1e31619
RDX: 0000000000000000 RSI: ffffffff8accbfe0 RDI: ffffffff8b2f1520
RBP: 0000000000000287 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8f18e357 R11: 0000000000000002 R12: 0000000000000000
R13: 1ffff92002c9afb3 R14: ffffffff81789850 R15: dffffc0000000000
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 unlock_timer kernel/time/posix-timers.c:128 [inline]
 do_timer_settime+0x260/0x2f0 kernel/time/posix-timers.c:934
 __do_sys_timer_settime kernel/time/posix-timers.c:954 [inline]
 __se_sys_timer_settime kernel/time/posix-timers.c:940 [inline]
 __x64_sys_timer_settime+0x266/0x2c0 kernel/time/posix-timers.c:940
 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: 0033:0x7fc9d9c7cae9
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:00007fc9da9cd0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000df
RAX: ffffffffffffffda RBX: 00007fc9d9d9c120 RCX: 00007fc9d9c7cae9
RDX: 0000000020000340 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fc9d9cc847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fc9d9d9c120 R15: 00007ffc40ae69b8
 </TASK>
----------------
Code disassembly (best guess):
   0:	f5                   	cmc
   1:	53                   	push   %rbx
   2:	48 8b 74 24 10       	mov    0x10(%rsp),%rsi
   7:	48 89 fb             	mov    %rdi,%rbx
   a:	48 83 c7 18          	add    $0x18,%rdi
   e:	e8 16 c8 e3 f6       	call   0xf6e3c829
  13:	48 89 df             	mov    %rbx,%rdi
  16:	e8 ce 3f e4 f6       	call   0xf6e43fe9
  1b:	f7 c5 00 02 00 00    	test   $0x200,%ebp
  21:	75 1f                	jne    0x42
  23:	9c                   	pushf
  24:	58                   	pop    %rax
  25:	f6 c4 02             	test   $0x2,%ah
  28:	75 2f                	jne    0x59
* 2a:	bf 01 00 00 00       	mov    $0x1,%edi <-- trapping instruction
  2f:	e8 85 ed d5 f6       	call   0xf6d5edb9
  34:	65 8b 05 a6 18 7f 75 	mov    %gs:0x757f18a6(%rip),%eax        # 0x757f18e1
  3b:	85 c0                	test   %eax,%eax
  3d:	74 12                	je     0x51
  3f:	5b                   	pop    %rbx