======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.0.1240/12537 is trying to acquire lock:
ffffffff8e849920 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_lock include/linux/cgroup.h:456 [inline]
ffffffff8e849920 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_kn_lock_live+0x116/0x520 kernel/cgroup/cgroup.c:1683
but task is already holding lock:
ffff88805a349440 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
ffff88805a349440 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: vfs_rmdir fs/namei.c:5351 [inline]
ffff88805a349440 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: vfs_rmdir+0xed/0x8a0 fs/namei.c:5339
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&type->i_mutex_dir_key#6){++++}-{4:4}:
down_read+0x99/0x450 kernel/locking/rwsem.c:1568
inode_lock_shared include/linux/fs.h:1044 [inline]
lookup_slow+0x42/0x70 fs/namei.c:1931
walk_component fs/namei.c:2278 [inline]
lookup_last fs/namei.c:2785 [inline]
path_lookupat+0x5e8/0xc40 fs/namei.c:2809
filename_lookup+0x202/0x590 fs/namei.c:2838
kern_path+0x37/0x50 fs/namei.c:3044
lookup_bdev+0xd8/0x280 block/bdev.c:1213
bdev_file_open_by_path+0x82/0x330 block/bdev.c:1086
add_device drivers/mtd/devices/block2mtd.c:279 [inline]
block2mtd_setup2.isra.0+0x2ee/0xc70 drivers/mtd/devices/block2mtd.c:459
block2mtd_setup+0xbd/0xd0 drivers/mtd/devices/block2mtd.c:476
param_attr_store+0x199/0x300 kernel/params.c:589
module_attr_store+0x58/0x80 kernel/params.c:904
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1070 fs/read_write.c:688
ksys_write+0x12a/0x250 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (param_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
ieee80211_rate_control_ops_get net/mac80211/rate.c:223 [inline]
rate_control_alloc net/mac80211/rate.c:269 [inline]
ieee80211_init_rate_ctrl_alg+0x1df/0x3b0 net/mac80211/rate.c:1016
ieee80211_register_hw+0x2c20/0x4570 net/mac80211/main.c:1559
mac80211_hwsim_new_radio+0x2a01/0x5aa0 drivers/net/wireless/virtual/mac80211_hwsim.c:6019
init_mac80211_hwsim+0x3f2/0x830 drivers/net/wireless/virtual/mac80211_hwsim.c:7394
do_one_initcall+0x121/0x750 init/main.c:1392
do_initcall_level init/main.c:1454 [inline]
do_initcalls init/main.c:1470 [inline]
do_basic_setup init/main.c:1490 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
kernel_init+0x1f/0x1e0 init/main.c:1593
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #1 (rtnl_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
cgrp_css_online+0xa1/0x1f0 net/core/netprio_cgroup.c:157
online_css+0xb2/0x350 kernel/cgroup/cgroup.c:5720
css_create kernel/cgroup/cgroup.c:5798 [inline]
cgroup_apply_control_enable+0xa8d/0xdd0 kernel/cgroup/cgroup.c:3351
cgroup_mkdir+0x59c/0x1310 kernel/cgroup/cgroup.c:5999
kernfs_iop_mkdir+0x111/0x190 fs/kernfs/dir.c:1306
vfs_mkdir+0x361/0x850 fs/namei.c:5261
filename_mkdirat+0x48b/0x5e0 fs/namei.c:5294
__do_sys_mkdirat fs/namei.c:5315 [inline]
__se_sys_mkdirat fs/namei.c:5312 [inline]
__x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5312
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (cgroup_mutex){+.+.}-{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+0x14b8/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
cgroup_lock include/linux/cgroup.h:456 [inline]
cgroup_kn_lock_live+0x116/0x520 kernel/cgroup/cgroup.c:1683
cgroup_rmdir+0x26/0x2e0 kernel/cgroup/cgroup.c:6259
kernfs_iop_rmdir+0x106/0x170 fs/kernfs/dir.c:1324
vfs_rmdir fs/namei.c:5366 [inline]
vfs_rmdir+0x328/0x8a0 fs/namei.c:5339
filename_rmdir+0x31a/0x5c0 fs/namei.c:5421
__do_sys_rmdir fs/namei.c:5444 [inline]
__se_sys_rmdir fs/namei.c:5441 [inline]
__x64_sys_rmdir+0x46/0x70 fs/namei.c:5441
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
cgroup_mutex --> param_lock --> &type->i_mutex_dir_key#6
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&type->i_mutex_dir_key#6);
lock(param_lock);
lock(&type->i_mutex_dir_key#6);
lock(cgroup_mutex);
*** DEADLOCK ***
3 locks held by syz.0.1240/12537:
#0: ffff888079a74410 (sb_writers#9){.+.+}-{0:0}, at: filename_rmdir+0x1ff/0x5c0 fs/namei.c:5410
#1: ffff88805a20b580 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
#1: ffff88805a20b580 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2914 [inline]
#1: ffff88805a20b580 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2938 [inline]
#1: ffff88805a20b580 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: filename_rmdir+0x258/0x5c0 fs/namei.c:5414
#2: ffff88805a349440 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#2: ffff88805a349440 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: vfs_rmdir fs/namei.c:5351 [inline]
#2: ffff88805a349440 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: vfs_rmdir+0xed/0x8a0 fs/namei.c:5339
stack backtrace:
CPU: 0 UID: 0 PID: 12537 Comm: syz.0.1240 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
check_noncircular+0x146/0x160 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+0x14b8/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
cgroup_lock include/linux/cgroup.h:456 [inline]
cgroup_kn_lock_live+0x116/0x520 kernel/cgroup/cgroup.c:1683
cgroup_rmdir+0x26/0x2e0 kernel/cgroup/cgroup.c:6259
kernfs_iop_rmdir+0x106/0x170 fs/kernfs/dir.c:1324
vfs_rmdir fs/namei.c:5366 [inline]
vfs_rmdir+0x328/0x8a0 fs/namei.c:5339
filename_rmdir+0x31a/0x5c0 fs/namei.c:5421
__do_sys_rmdir fs/namei.c:5444 [inline]
__se_sys_rmdir fs/namei.c:5441 [inline]
__x64_sys_rmdir+0x46/0x70 fs/namei.c:5441
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8a08b9ce59
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:00007f8a09aa9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007f8a08e16180 RCX: 00007f8a08b9ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000080
RBP: 00007f8a08c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8a08e16218 R14: 00007f8a08e16180 R15: 00007ffc54d072c8
</TASK>