====================================================== WARNING: possible circular locking dependency detected 6.4.0-rc4-syzkaller-gcd6bd67ad7ab #0 Not tainted ------------------------------------------------------ syz-executor.4/6190 is trying to acquire lock: ffff80008df30cd0 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_slow_inc+0x1c/0x40 kernel/jump_label.c:185 but task is already holding lock: ffff80008e0c3428 (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+0x2c/0x38 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:4071 kernfs_fop_write_iter+0x334/0x48c fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:1868 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x618/0x918 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+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 -> #0 (cpu_hotplug_lock){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3113 [inline] check_prevs_add kernel/locking/lockdep.c:3232 [inline] validate_chain kernel/locking/lockdep.c:3847 [inline] __lock_acquire+0x3308/0x7604 kernel/locking/lockdep.c:5088 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x58/0x2a4 kernel/cpu.c:310 static_key_slow_inc+0x1c/0x40 kernel/jump_label.c:185 freezer_css_online+0xbc/0x150 kernel/cgroup/legacy_freezer.c:117 online_css+0xc8/0x2b4 kernel/cgroup/cgroup.c:5491 css_create kernel/cgroup/cgroup.c:5562 [inline] cgroup_apply_control_enable+0x6d8/0x9ac kernel/cgroup/cgroup.c:3249 cgroup_mkdir+0x9b4/0xd50 kernel/cgroup/cgroup.c:5758 kernfs_iop_mkdir+0x22c/0x3bc fs/kernfs/dir.c:1219 vfs_mkdir+0x240/0x3a8 fs/namei.c:4115 do_mkdirat+0x20c/0x610 fs/namei.c:4138 __do_sys_mkdirat fs/namei.c:4153 [inline] __se_sys_mkdirat fs/namei.c:4151 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4151 __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+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(freezer_mutex); lock(cpu_hotplug_lock); lock(freezer_mutex); rlock(cpu_hotplug_lock); *** DEADLOCK *** 4 locks held by syz-executor.4/6190: #0: ffff0000c6d2c460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:394 #1: ffff00012f4eb900 (&type->i_mutex_dir_key#7/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:810 [inline] #1: ffff00012f4eb900 (&type->i_mutex_dir_key#7/1){+.+.}-{3:3}, at: filename_create+0x204/0x468 fs/namei.c:3884 #2: ffff80008e0b8ba8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:370 [inline] #2: ffff80008e0b8ba8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xf8/0x258 kernel/cgroup/cgroup.c:1683 #3: ffff80008e0c3428 (freezer_mutex){+.+.}-{3:3}, at: freezer_css_online+0x50/0x150 kernel/cgroup/legacy_freezer.c:111 stack backtrace: CPU: 0 PID: 6190 Comm: syz-executor.4 Not tainted 6.4.0-rc4-syzkaller-gcd6bd67ad7ab #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2066 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2188 check_prev_add kernel/locking/lockdep.c:3113 [inline] check_prevs_add kernel/locking/lockdep.c:3232 [inline] validate_chain kernel/locking/lockdep.c:3847 [inline] __lock_acquire+0x3308/0x7604 kernel/locking/lockdep.c:5088 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x58/0x2a4 kernel/cpu.c:310 static_key_slow_inc+0x1c/0x40 kernel/jump_label.c:185 freezer_css_online+0xbc/0x150 kernel/cgroup/legacy_freezer.c:117 online_css+0xc8/0x2b4 kernel/cgroup/cgroup.c:5491 css_create kernel/cgroup/cgroup.c:5562 [inline] cgroup_apply_control_enable+0x6d8/0x9ac kernel/cgroup/cgroup.c:3249 cgroup_mkdir+0x9b4/0xd50 kernel/cgroup/cgroup.c:5758 kernfs_iop_mkdir+0x22c/0x3bc fs/kernfs/dir.c:1219 vfs_mkdir+0x240/0x3a8 fs/namei.c:4115 do_mkdirat+0x20c/0x610 fs/namei.c:4138 __do_sys_mkdirat fs/namei.c:4153 [inline] __se_sys_mkdirat fs/namei.c:4151 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4151 __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+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591