======================================================
WARNING: possible circular locking dependency detected
6.1.35-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/23981 is trying to acquire lock:
ffff800015635450 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_slow_inc+0x1c/0x38 kernel/jump_label.c:158

but task is already holding lock:
ffff8000157c6c88 (freezer_mutex){+.+.}-{3:3}, at: freezer_css_online+0x50/0x150 kernel/cgroup/legacy_freezer.c:111

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (freezer_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       freezer_change_state kernel/cgroup/legacy_freezer.c:389 [inline]
       freezer_write+0xc4/0x43c kernel/cgroup/legacy_freezer.c:429
       cgroup_file_write+0x258/0x5ac kernel/cgroup/cgroup.c:4057
       kernfs_fop_write_iter+0x334/0x48c fs/kernfs/file.c:330
       call_write_iter include/linux/fs.h:2205 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x610/0x914 fs/read_write.c:584
       ksys_write+0x15c/0x26c fs/read_write.c:637
       __do_sys_write fs/read_write.c:649 [inline]
       __se_sys_write fs/read_write.c:646 [inline]
       __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

-> #0 (cpu_hotplug_lock){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain kernel/locking/lockdep.c:3832 [inline]
       __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       cpus_read_lock+0x70/0x2bc kernel/cpu.c:310
       static_key_slow_inc+0x1c/0x38 kernel/jump_label.c:158
       freezer_css_online+0xbc/0x150 kernel/cgroup/legacy_freezer.c:117
       online_css+0xc8/0x2b4 kernel/cgroup/cgroup.c:5476
       css_create kernel/cgroup/cgroup.c:5547 [inline]
       cgroup_apply_control_enable+0x6d8/0x9ac kernel/cgroup/cgroup.c:3235
       cgroup_mkdir+0x9b4/0xd50 kernel/cgroup/cgroup.c:5743
       kernfs_iop_mkdir+0x114/0x160 fs/kernfs/dir.c:1196
       vfs_mkdir+0x334/0x4e4 fs/namei.c:4036
       do_mkdirat+0x20c/0x610 fs/namei.c:4061
       __do_sys_mkdirat fs/namei.c:4076 [inline]
       __se_sys_mkdirat fs/namei.c:4074 [inline]
       __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4074
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(
freezer_mutex);
                               lock(cpu_hotplug_lock
);
                               lock(freezer_mutex);
  lock(
cpu_hotplug_lock);

 *** DEADLOCK ***

4 locks held by syz-executor.3/23981:
 #0: ffff0000d5e58460 (
sb_writers#9){.+.+}-{0:0}
, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
 #1: ffff0000cb51b900 (&type->i_mutex_dir_key#7/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
 #1: ffff0000cb51b900 (&type->i_mutex_dir_key#7/1){+.+.}-{3:3}, at: filename_create+0x200/0x464 fs/namei.c:3807
 #2: ffff8000157bc3c8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
 #2: ffff8000157bc3c8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xf8/0x258 kernel/cgroup/cgroup.c:1667
 #3: ffff8000157c6c88 (freezer_mutex){+.+.}-{3:3}, at: freezer_css_online+0x50/0x150 kernel/cgroup/legacy_freezer.c:111

stack backtrace:
CPU: 1 PID: 23981 Comm: syz-executor.3 Not tainted 6.1.35-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain kernel/locking/lockdep.c:3832 [inline]
 __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 cpus_read_lock+0x70/0x2bc kernel/cpu.c:310
 static_key_slow_inc+0x1c/0x38 kernel/jump_label.c:158
 freezer_css_online+0xbc/0x150 kernel/cgroup/legacy_freezer.c:117
 online_css+0xc8/0x2b4 kernel/cgroup/cgroup.c:5476
 css_create kernel/cgroup/cgroup.c:5547 [inline]
 cgroup_apply_control_enable+0x6d8/0x9ac kernel/cgroup/cgroup.c:3235
 cgroup_mkdir+0x9b4/0xd50 kernel/cgroup/cgroup.c:5743
 kernfs_iop_mkdir+0x114/0x160 fs/kernfs/dir.c:1196
 vfs_mkdir+0x334/0x4e4 fs/namei.c:4036
 do_mkdirat+0x20c/0x610 fs/namei.c:4061
 __do_sys_mkdirat fs/namei.c:4076 [inline]
 __se_sys_mkdirat fs/namei.c:4074 [inline]
 __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4074
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581