syzbot

================================
WARNING: inconsistent lock state
syzkaller #0 Tainted: G             L     
--------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
syz.2.1847/12914 [HC1[1]:SC0[0]:HE0:SE1] takes:
ffff888032c07068 (&dev->spinlock){?...}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
ffff888032c07068 (&dev->spinlock){?...}-{3:3}, at: das16m1_interrupt+0x68/0x120 drivers/comedi/drivers/das16m1.c:460
{HARDIRQ-ON-W} state was registered at:
  lock_acquire kernel/locking/lockdep.c:5868 [inline]
  lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
  __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline]
  _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
  spin_lock_bh include/linux/spinlock.h:347 [inline]
  waveform_ao_cancel+0x96/0x150 drivers/comedi/drivers/comedi_test.c:628
  do_cancel+0xf4/0x180 drivers/comedi/comedi_fops.c:818
  comedi_close+0x2f6/0x470 drivers/comedi/comedi_fops.c:3036
  __fput+0x3ff/0xb40 fs/file_table.c:469
  task_work_run+0x150/0x240 kernel/task_work.c:233
  resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
  __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
  exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98
  __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
  syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
  syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
  do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
irq event stamp: 2574
hardirqs last  enabled at (2573): [<ffffffff8b93e153>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:187 [inline]
hardirqs last  enabled at (2573): [<ffffffff8b93e153>] _raw_spin_unlock_irq+0x23/0x50 kernel/locking/spinlock.c:202
hardirqs last disabled at (2574): [<ffffffff8b90bdc9>] common_interrupt+0x19/0xe0 arch/x86/kernel/irq.c:326
softirqs last  enabled at (2566): [<ffffffff81c9240f>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last  enabled at (2566): [<ffffffff81c9240f>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last  enabled at (2566): [<ffffffff81c9240f>] __irq_exit_rcu+0xef/0x150 kernel/softirq.c:723
softirqs last disabled at (2557): [<ffffffff81c9240f>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (2557): [<ffffffff81c9240f>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (2557): [<ffffffff81c9240f>] __irq_exit_rcu+0xef/0x150 kernel/softirq.c:723

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

       CPU0
       ----
  lock(&dev->spinlock);
  <Interrupt>
    lock(&dev->spinlock);

 *** DEADLOCK ***

3 locks held by syz.2.1847/12914:
 #0: ffff888037695900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff888037695900 (&mm->mmap_lock){++++}-{4:4}, at: __mm_populate+0x229/0x3a0 mm/gup.c:1942
 #1: ffffffff8e7e7920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #1: ffffffff8e7e7920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #1: ffffffff8e7e7920 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x310 mm/pgtable-generic.c:288
 #2: ffff888078312138 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
 #2: ffff888078312138 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:402

stack backtrace:
CPU: 1 UID: 0 PID: 12914 Comm: syz.2.1847 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_usage_bug.part.0+0x257/0x340 kernel/locking/lockdep.c:4042
 print_usage_bug kernel/locking/lockdep.c:4010 [inline]
 valid_state kernel/locking/lockdep.c:4056 [inline]
 mark_lock_irq kernel/locking/lockdep.c:4267 [inline]
 mark_lock+0x74a/0xa20 kernel/locking/lockdep.c:4753
 mark_usage kernel/locking/lockdep.c:4639 [inline]
 __lock_acquire+0x10ff/0x2630 kernel/locking/lockdep.c:5191
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:341 [inline]
 das16m1_interrupt+0x68/0x120 drivers/comedi/drivers/das16m1.c:460
 __handle_irq_event_percpu+0x232/0x8e0 kernel/irq/handle.c:209
 handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
 handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:263
 handle_edge_irq+0x375/0x970 kernel/irq/chip.c:855
 generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
 handle_irq arch/x86/kernel/irq.c:262 [inline]
 call_irq_handler arch/x86/kernel/irq.c:318 [inline]
 __common_interrupt+0xd8/0x2f0 arch/x86/kernel/irq.c:333
 common_interrupt+0xb9/0xe0 arch/x86/kernel/irq.c:326
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_release kernel/locking/lockdep.c:5885 [inline]
RIP: 0010:lock_release+0x8d/0x320 kernel/locking/lockdep.c:5875
Code: 00 00 65 4c 8b 25 2b 40 29 12 41 8b bc 24 54 0b 00 00 85 ff 0f 85 21 01 00 00 48 81 3b 40 27 15 94 0f 84 14 01 00 00 9c 41 5e <fa> 48 c7 c7 07 bc f6 8d e8 f6 04 ac 09 65 ff 05 67 87 29 12 8b 35
RSP: 0018:ffffc9000da0f958 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffff888078312138 RCX: ffffc9000ea11000
RDX: 0000000000000000 RSI: ffffffff8c1b19a0 RDI: 0000000000000000
RBP: ffffffff825695e5 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88804655c980
R13: 0000000000000000 R14: 0000000000000287 R15: 1ffff92001b41f3d
 __raw_spin_unlock include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:389 [inline]
 follow_page_pte+0x8b5/0x1400 mm/gup.c:889
 follow_pmd_mask mm/gup.c:928 [inline]
 follow_pud_mask mm/gup.c:967 [inline]
 follow_p4d_mask mm/gup.c:984 [inline]
 follow_page_mask mm/gup.c:1023 [inline]
 __get_user_pages+0x745/0x34d0 mm/gup.c:1426
 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860
 __mm_populate+0x107/0x3a0 mm/gup.c:1963
 mm_populate include/linux/mm.h:3894 [inline]
 vm_mmap_pgoff+0x37f/0x470 mm/util.c:586
 ksys_mmap_pgoff+0xe1/0x650 mm/mmap.c:605
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe1d3f9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe1d4e7b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe1d4215fa0 RCX: 00007fe1d3f9c819
RDX: 0000000002000001 RSI: 0000000000600000 RDI: 00002000009fd000
RBP: 00007fe1d4032c91 R08: ffffffffffffffff R09: 0000000000002000
R10: 0000000000006031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe1d4216038 R14: 00007fe1d4215fa0 R15: 00007fff06dc2158
 </TASK>
comedi comedi2: fifo overflow
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	65 4c 8b 25 2b 40 29 	mov    %gs:0x1229402b(%rip),%r12        # 0x12294035
   9:	12
   a:	41 8b bc 24 54 0b 00 	mov    0xb54(%r12),%edi
  11:	00
  12:	85 ff                	test   %edi,%edi
  14:	0f 85 21 01 00 00    	jne    0x13b
  1a:	48 81 3b 40 27 15 94 	cmpq   $0xffffffff94152740,(%rbx)
  21:	0f 84 14 01 00 00    	je     0x13b
  27:	9c                   	pushf
  28:	41 5e                	pop    %r14
* 2a:	fa                   	cli <-- trapping instruction
  2b:	48 c7 c7 07 bc f6 8d 	mov    $0xffffffff8df6bc07,%rdi
  32:	e8 f6 04 ac 09       	call   0x9ac052d
  37:	65 ff 05 67 87 29 12 	incl   %gs:0x12298767(%rip)        # 0x122987a5
  3e:	8b                   	.byte 0x8b
  3f:	35                   	.byte 0x35