EXT4-fs error (device sda1): ext4_lookup:1787: inode #274: comm syz.4.1983: 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 Not tainted ------------------------------------------------------ syz.4.1983/17054 is trying to acquire lock: ffffffff8e4751d0 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xa9/0x250 kernel/umh.c:214 but task is already holding lock: ffffffff8f5173c8 (dpm_list_mtx){+.+.}-{4:4}, at: device_pm_lock drivers/base/power/main.c:128 [inline] ffffffff8f5173c8 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev drivers/base/power/main.c:2290 [inline] ffffffff8f5173c8 (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+0x5d4/0x6f0 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+0x5a/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/0x490 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.4.1983/17054: #0: ffffffff8f306f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 #1: ffffffff8e484808 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:57 #2: ffffffff8e4c4c70 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust kernel/notifier.c:344 [inline] #2: ffffffff8e4c4c70 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust+0xa8/0x160 kernel/notifier.c:333 #3: ffffffff8f51c9c8 (fw_lock){+.+.}-{4:4}, at: device_cache_fw_images drivers/base/firmware_loader/main.c:1513 [inline] #3: ffffffff8f51c9c8 (fw_lock){+.+.}-{4:4}, at: fw_pm_notify+0x69/0x150 drivers/base/firmware_loader/main.c:1566 #4: ffffffff8f5173c8 (dpm_list_mtx){+.+.}-{4:4}, at: device_pm_lock drivers/base/power/main.c:128 [inline] #4: ffffffff8f5173c8 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev drivers/base/power/main.c:2290 [inline] #4: ffffffff8f5173c8 (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: 17054 Comm: syz.4.1983 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __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+0x5a/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/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe5da58ebe9 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:00007fe5db48d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fe5da7b5fa0 RCX: 00007fe5da58ebe9 RDX: 0000000000000101 RSI: 0000200000000180 RDI: ffffffffffffff9c RBP: 00007fe5da611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe5da7b6038 R14: 00007fe5da7b5fa0 R15: 00007ffd0ab287a8