random: crng reseeded on system resumption
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 1
CPU: 0 UID: 0 PID: 5326 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x412/0x560 lib/fault-inject.c:174
 should_failslab+0xa8/0x100 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4495 [inline]
 slab_alloc_node mm/slub.c:4846 [inline]
 __kmalloc_cache_noprof+0x88/0x660 mm/slub.c:5378
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 async_schedule_node_domain+0x5b/0x120 kernel/async.c:208
 async_schedule_domain include/linux/async.h:72 [inline]
 dev_cache_fw_image+0x36c/0x3f0 drivers/base/firmware_loader/main.c:1456
 dpm_for_each_dev+0x56/0xb0 drivers/base/power/main.c:2326
 device_cache_fw_images drivers/base/firmware_loader/main.c:1506 [inline]
 fw_pm_notify+0x20c/0x2d0 drivers/base/firmware_loader/main.c:1557
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 notifier_call_chain_robust kernel/notifier.c:120 [inline]
 blocking_notifier_call_chain_robust+0x85/0x100 kernel/notifier.c:345
 pm_notifier_call_chain_robust+0x2c/0x60 kernel/power/main.c:172
 snapshot_open+0x133/0x280 kernel/power/user.c:87
 misc_open+0x2d5/0x350 drivers/char/misc.c:163
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
 do_dentry_open+0x785/0x14e0 fs/open.c:949
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f960d79c799
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:00007f960e6a6fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f960da15fa0 RCX: 00007f960d79c799
RDX: 0000000000042801 RSI: 00002000000002c0 RDI: ffffffffffffff9c
RBP: 00007f960e6a7050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f960da16038 R14: 00007f960da15fa0 R15: 00007fff62f72288
 </TASK>
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.0/5326 is trying to acquire lock:
ffffffff8f1936a8 (fw_lock){+.+.}-{4:4}, at: assign_fw+0x52/0x8d0 drivers/base/firmware_loader/main.c:700

but task is already holding lock:
ffffffff8f1936a8 (fw_lock){+.+.}-{4:4}, at: device_cache_fw_images drivers/base/firmware_loader/main.c:1504 [inline]
ffffffff8f1936a8 (fw_lock){+.+.}-{4:4}, at: fw_pm_notify+0x1f4/0x2d0 drivers/base/firmware_loader/main.c:1557

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

       CPU0
       ----
  lock(fw_lock);
  lock(fw_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz.0.0/5326:
 #0: ffffffff8f019e28 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125
 #1: ffffffff8e607d68 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x49/0x70 kernel/power/main.c:71
 #2: ffffffff8e62f350 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust+0x65/0x100 kernel/notifier.c:344
 #3: ffffffff8f1936a8 (fw_lock){+.+.}-{4:4}, at: device_cache_fw_images drivers/base/firmware_loader/main.c:1504 [inline]
 #3: ffffffff8f1936a8 (fw_lock){+.+.}-{4:4}, at: fw_pm_notify+0x1f4/0x2d0 drivers/base/firmware_loader/main.c:1557
 #4: ffffffff8f18e548 (dpm_list_mtx){+.+.}-{4:4}, at: device_pm_lock drivers/base/power/main.c:127 [inline]
 #4: ffffffff8f18e548 (dpm_list_mtx){+.+.}-{4:4}, at: dpm_for_each_dev+0x29/0xb0 drivers/base/power/main.c:2324

stack backtrace:
CPU: 0 UID: 0 PID: 5326 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x253f/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
 __mutex_lock_common kernel/locking/mutex.c:614 [inline]
 __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776
 assign_fw+0x52/0x8d0 drivers/base/firmware_loader/main.c:700
 _request_firmware+0xfb6/0x1780 drivers/base/firmware_loader/main.c:901
 request_firmware drivers/base/firmware_loader/main.c:948 [inline]
 cache_firmware drivers/base/firmware_loader/main.c:1286 [inline]
 __async_dev_cache_fw_image+0x7f/0x2d0 drivers/base/firmware_loader/main.c:1400
 async_schedule_node_domain+0xe1/0x120 kernel/async.c:221
 async_schedule_domain include/linux/async.h:72 [inline]
 dev_cache_fw_image+0x36c/0x3f0 drivers/base/firmware_loader/main.c:1456
 dpm_for_each_dev+0x56/0xb0 drivers/base/power/main.c:2326
 device_cache_fw_images drivers/base/firmware_loader/main.c:1506 [inline]
 fw_pm_notify+0x20c/0x2d0 drivers/base/firmware_loader/main.c:1557
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 notifier_call_chain_robust kernel/notifier.c:120 [inline]
 blocking_notifier_call_chain_robust+0x85/0x100 kernel/notifier.c:345
 pm_notifier_call_chain_robust+0x2c/0x60 kernel/power/main.c:172
 snapshot_open+0x133/0x280 kernel/power/user.c:87
 misc_open+0x2d5/0x350 drivers/char/misc.c:163
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
 do_dentry_open+0x785/0x14e0 fs/open.c:949
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f960d79c799
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:00007f960e6a6fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f960da15fa0 RCX: 00007f960d79c799
RDX: 0000000000042801 RSI: 00002000000002c0 RDI: ffffffffffffff9c
RBP: 00007f960e6a7050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f960da16038 R14: 00007f960da15fa0 R15: 00007fff62f72288
 </TASK>