====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.1.829/9762 is trying to acquire lock: ffff800088d607e0 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_lock include/linux/cgroup.h:456 [inline] ffff800088d607e0 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_kn_lock_live+0xdc/0x158 kernel/cgroup/cgroup.c:1717 but task is already holding lock: ffff0000ed1d6740 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff0000ed1d6740 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: vfs_rmdir+0x118/0x590 fs/namei.c:5366 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&type->i_mutex_dir_key#6){++++}-{4:4}: down_read+0x58/0x2bc kernel/locking/rwsem.c:1574 inode_lock_shared include/linux/fs.h:1039 [inline] lookup_slow+0x50/0x84 fs/namei.c:1935 lookup_one_unlocked+0x88/0xa4 fs/namei.c:3238 ovl_lookup_positive_unlocked fs/overlayfs/namei.c:216 [inline] ovl_lookup_single+0x25c/0xb74 fs/overlayfs/namei.c:260 ovl_lookup_layer+0x2e8/0x3ac fs/overlayfs/namei.c:365 ovl_lookup_layers fs/overlayfs/namei.c:1168 [inline] ovl_lookup+0x830/0x162c fs/overlayfs/namei.c:1403 lookup_open fs/namei.c:4481 [inline] open_last_lookups fs/namei.c:4608 [inline] path_openat+0xda4/0x2a60 fs/namei.c:4860 do_file_open+0x1c8/0x2e8 fs/namei.c:4892 do_sys_openat2+0x114/0x1e8 fs/open.c:1368 do_sys_open+0xb0/0xe0 fs/open.c:1374 __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __arm64_sys_openat+0xa8/0xc4 fs/open.c:1385 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 -> #3 (&ovl_i_mutex_dir_key[depth]#2){++++}-{4:4}: down_read+0x58/0x2bc kernel/locking/rwsem.c:1574 inode_lock_shared include/linux/fs.h:1039 [inline] lookup_slow+0x50/0x84 fs/namei.c:1935 walk_component fs/namei.c:2282 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x358/0x798 fs/namei.c:2813 filename_lookup+0x1d0/0x3c8 fs/namei.c:2842 kern_path+0x4c/0x70 fs/namei.c:3036 lookup_bdev+0xc0/0x248 block/bdev.c:1208 bdev_file_open_by_path+0x48/0x234 block/bdev.c:1081 add_device drivers/mtd/devices/block2mtd.c:279 [inline] block2mtd_setup2+0x3ec/0xb18 drivers/mtd/devices/block2mtd.c:459 block2mtd_setup+0x34/0xe0 drivers/mtd/devices/block2mtd.c:476 param_attr_store+0x144/0x1bc kernel/params.c:589 module_attr_store+0x6c/0x94 kernel/params.c:904 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345 do_iter_readv_writev+0x48c/0x6f8 fs/read_write.c:-1 vfs_writev+0x2a8/0x630 fs/read_write.c:1058 do_pwritev+0x11c/0x224 fs/read_write.c:1154 __do_sys_pwritev fs/read_write.c:1200 [inline] __se_sys_pwritev fs/read_write.c:1195 [inline] __arm64_sys_pwritev+0xac/0xc4 fs/read_write.c:1195 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 -> #2 (param_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0xf14 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 kernel_param_lock+0x34/0x44 kernel/params.c:602 ieee80211_rate_control_ops_get net/mac80211/rate.c:221 [inline] rate_control_alloc net/mac80211/rate.c:267 [inline] ieee80211_init_rate_ctrl_alg+0x14c/0x394 net/mac80211/rate.c:1008 ieee80211_register_hw+0x268c/0x35f4 net/mac80211/main.c:1562 mac80211_hwsim_new_radio+0x2594/0x43c8 drivers/net/wireless/virtual/mac80211_hwsim_main.c:6113 init_mac80211_hwsim+0x2e0/0x3b4 drivers/net/wireless/virtual/mac80211_hwsim_main.c:7571 do_one_initcall+0x274/0xc38 init/main.c:1347 do_initcall_level+0x12c/0x1c4 init/main.c:1409 do_initcalls+0x70/0xd0 init/main.c:1425 do_basic_setup+0x7c/0x90 init/main.c:1445 kernel_init_freeable+0x268/0x3a8 init/main.c:1658 kernel_init+0x24/0x1dc init/main.c:1548 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838 -> #1 (rtnl_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0xf14 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80 cgrp_css_online+0x80/0x130 net/core/netprio_cgroup.c:157 online_css+0xc8/0x334 kernel/cgroup/cgroup.c:5793 css_create kernel/cgroup/cgroup.c:5871 [inline] cgroup_apply_control_enable+0x7f0/0xae8 kernel/cgroup/cgroup.c:3385 cgroup_mkdir+0x768/0xbac kernel/cgroup/cgroup.c:6072 kernfs_iop_mkdir+0xe0/0x128 fs/kernfs/dir.c:1305 vfs_mkdir+0x2dc/0x464 fs/namei.c:5276 filename_mkdirat+0x228/0x3f4 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat fs/namei.c:5327 [inline] __arm64_sys_mkdirat+0x9c/0xc0 fs/namei.c:5327 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 -> #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+0x17c0/0x2ebc kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x364 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0xf14 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 cgroup_lock include/linux/cgroup.h:456 [inline] cgroup_kn_lock_live+0xdc/0x158 kernel/cgroup/cgroup.c:1717 cgroup_rmdir+0x38/0x52c kernel/cgroup/cgroup.c:6324 kernfs_iop_rmdir+0xe0/0x124 fs/kernfs/dir.c:1323 vfs_rmdir+0x354/0x590 fs/namei.c:5381 filename_rmdir+0x208/0x3d0 fs/namei.c:5438 __do_sys_unlinkat fs/namei.c:5613 [inline] __se_sys_unlinkat fs/namei.c:5606 [inline] __arm64_sys_unlinkat+0xcc/0x108 fs/namei.c:5606 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 other info that might help us debug this: Chain exists of: cgroup_mutex --> &ovl_i_mutex_dir_key[depth]#2 --> &type->i_mutex_dir_key#6 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&type->i_mutex_dir_key#6); lock(&ovl_i_mutex_dir_key[depth]#2); lock(&type->i_mutex_dir_key#6); lock(cgroup_mutex); *** DEADLOCK *** 3 locks held by syz.1.829/9762: #0: ffff0000d3dea450 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:494 #1: ffff0000da5f5900 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline] #1: ffff0000da5f5900 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: __start_dirop+0xa0/0xf4 fs/namei.c:2918 #2: ffff0000ed1d6740 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #2: ffff0000ed1d6740 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: vfs_rmdir+0x118/0x590 fs/namei.c:5366 stack backtrace: CPU: 0 UID: 0 PID: 9762 Comm: syz.1.829 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2043 check_noncircular+0x158/0x174 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+0x17c0/0x2ebc kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x364 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0xf14 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 cgroup_lock include/linux/cgroup.h:456 [inline] cgroup_kn_lock_live+0xdc/0x158 kernel/cgroup/cgroup.c:1717 cgroup_rmdir+0x38/0x52c kernel/cgroup/cgroup.c:6324 kernfs_iop_rmdir+0xe0/0x124 fs/kernfs/dir.c:1323 vfs_rmdir+0x354/0x590 fs/namei.c:5381 filename_rmdir+0x208/0x3d0 fs/namei.c:5438 __do_sys_unlinkat fs/namei.c:5613 [inline] __se_sys_unlinkat fs/namei.c:5606 [inline] __arm64_sys_unlinkat+0xcc/0x108 fs/namei.c:5606 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590