EXT4-fs error (device sda1): ext4_lookup:1787: inode #274: comm syz.4.5929: iget: checksum invalid
(NULL device *): loading /lib/firmware/regulatory.db failed with error -74
(NULL device *): Direct firmware load for regulatory.db failed with error -74
(NULL device *): Falling back to sysfs fallback for: regulatory.db
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G     U             
------------------------------------------------------
syz.4.5929/14370 is trying to acquire lock:
ffffffff8e475550 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xa9/0x250 kernel/umh.c:214

but task is already holding lock:
ffffffff8f518668 (dpm_list_mtx){+.+.}-{4:4}, at: device_pm_lock drivers/base/power/main.c:128 [inline]
ffffffff8f518668 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev drivers/base/power/main.c:2290 [inline]
ffffffff8f518668 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev+0x2d/0xb0 drivers/base/power/main.c:2283

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (dpm_list_mtx){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:598 [inline]
       __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
       device_pm_add+0x87/0x3e0 drivers/base/power/main.c:152
       device_add+0x9cd/0x1aa0 drivers/base/core.c:3652
       fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:86 [inline]
       fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:162 [inline]
       firmware_fallback_sysfs+0x2ec/0xbe0 drivers/base/firmware_loader/fallback.c:238
       _request_firmware+0xfe9/0x1470 drivers/base/firmware_loader/main.c:906
       request_firmware_work_func+0xea/0x250 drivers/base/firmware_loader/main.c:1159
       process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236
       process_scheduled_works kernel/workqueue.c:3319 [inline]
       worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
       kthread+0x3c5/0x780 kernel/kthread.c:463
       ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (umhelper_sem){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
       down_read+0x9b/0x480 kernel/locking/rwsem.c:1537
       usermodehelper_read_trylock+0xa9/0x250 kernel/umh.c:214
       fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:147 [inline]
       firmware_fallback_sysfs+0x6ba/0xbe0 drivers/base/firmware_loader/fallback.c:238
       _request_firmware+0xfe9/0x1470 drivers/base/firmware_loader/main.c:906
       request_firmware drivers/base/firmware_loader/main.c:957 [inline]
       cache_firmware drivers/base/firmware_loader/main.c:1295 [inline]
       __async_dev_cache_fw_image+0xb1/0x340 drivers/base/firmware_loader/main.c:1409
       async_schedule_node_domain+0xd4/0x120 kernel/async.c:221
       async_schedule_domain include/linux/async.h:72 [inline]
       dev_cache_fw_image+0x38e/0x490 drivers/base/firmware_loader/main.c:1465
       dpm_for_each_dev drivers/base/power/main.c:2292 [inline]
       dpm_for_each_dev+0x5d/0xb0 drivers/base/power/main.c:2283
       device_cache_fw_images drivers/base/firmware_loader/main.c:1515 [inline]
       fw_pm_notify+0x81/0x150 drivers/base/firmware_loader/main.c:1566
       notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
       notifier_call_chain_robust kernel/notifier.c:120 [inline]
       blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline]
       blocking_notifier_call_chain_robust+0xc8/0x160 kernel/notifier.c:333
       pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:103
       snapshot_open+0x218/0x2b0 kernel/power/user.c:87
       misc_open+0x35a/0x420 drivers/char/misc.c:161
       chrdev_open+0x234/0x6a0 fs/char_dev.c:414
       do_dentry_open+0x982/0x1530 fs/open.c:965
       vfs_open+0x82/0x3f0 fs/open.c:1095
       do_open fs/namei.c:3887 [inline]
       path_openat+0x1de4/0x2cb0 fs/namei.c:4046
       do_filp_open+0x20b/0x470 fs/namei.c:4073
       do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
       do_sys_open fs/open.c:1450 [inline]
       __do_sys_openat fs/open.c:1466 [inline]
       __se_sys_openat fs/open.c:1461 [inline]
       __x64_sys_openat+0x174/0x210 fs/open.c:1461
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(dpm_list_mtx);
                               lock(umhelper_sem);
                               lock(dpm_list_mtx);
  rlock(umhelper_sem);

 *** DEADLOCK ***

5 locks held by syz.4.5929/14370:
 #0: ffffffff8f3080e8 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125
 #1: ffffffff8e484b88 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:57
 #2: ffffffff8e4c4ff0 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust kernel/notifier.c:344 [inline]
 #2: ffffffff8e4c4ff0 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust+0xa8/0x160 kernel/notifier.c:333
 #3: ffffffff8f51dc68 (fw_lock){+.+.}-{4:4}, at: device_cache_fw_images drivers/base/firmware_loader/main.c:1513 [inline]
 #3: ffffffff8f51dc68 (fw_lock){+.+.}-{4:4}, at: fw_pm_notify+0x69/0x150 drivers/base/firmware_loader/main.c:1566
 #4: ffffffff8f518668 (dpm_list_mtx){+.+.}-{4:4}, at: device_pm_lock drivers/base/power/main.c:128 [inline]
 #4: ffffffff8f518668 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev drivers/base/power/main.c:2290 [inline]
 #4: ffffffff8f518668 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev+0x2d/0xb0 drivers/base/power/main.c:2283

stack backtrace:
CPU: 0 UID: 0 PID: 14370 Comm: syz.4.5929 Tainted: G     U              syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2043
 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
 down_read+0x9b/0x480 kernel/locking/rwsem.c:1537
 usermodehelper_read_trylock+0xa9/0x250 kernel/umh.c:214
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:147 [inline]
 firmware_fallback_sysfs+0x6ba/0xbe0 drivers/base/firmware_loader/fallback.c:238
 _request_firmware+0xfe9/0x1470 drivers/base/firmware_loader/main.c:906
 request_firmware drivers/base/firmware_loader/main.c:957 [inline]
 cache_firmware drivers/base/firmware_loader/main.c:1295 [inline]
 __async_dev_cache_fw_image+0xb1/0x340 drivers/base/firmware_loader/main.c:1409
 async_schedule_node_domain+0xd4/0x120 kernel/async.c:221
 async_schedule_domain include/linux/async.h:72 [inline]
 dev_cache_fw_image+0x38e/0x490 drivers/base/firmware_loader/main.c:1465
 dpm_for_each_dev drivers/base/power/main.c:2292 [inline]
 dpm_for_each_dev+0x5d/0xb0 drivers/base/power/main.c:2283
 device_cache_fw_images drivers/base/firmware_loader/main.c:1515 [inline]
 fw_pm_notify+0x81/0x150 drivers/base/firmware_loader/main.c:1566
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
 notifier_call_chain_robust kernel/notifier.c:120 [inline]
 blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline]
 blocking_notifier_call_chain_robust+0xc8/0x160 kernel/notifier.c:333
 pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:103
 snapshot_open+0x218/0x2b0 kernel/power/user.c:87
 misc_open+0x35a/0x420 drivers/char/misc.c:161
 chrdev_open+0x234/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x982/0x1530 fs/open.c:965
 vfs_open+0x82/0x3f0 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4046
 do_filp_open+0x20b/0x470 fs/namei.c:4073
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f43d378eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f43d4569038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f43d39e6090 RCX: 00007f43d378eec9
RDX: 0000000000080643 RSI: 0000200000001940 RDI: ffffffffffffff9c
RBP: 00007f43d3811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f43d39e6128 R14: 00007f43d39e6090 R15: 00007ffcb07240e8
 </TASK>