overlayfs: upperdir is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.4.1160/9782 is trying to acquire lock: ffff0000f2a1de58 (&ovl_i_mutex_dir_key[depth]#2){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline] ffff0000f2a1de58 (&ovl_i_mutex_dir_key[depth]#2){++++}-{4:4}, at: lookup_slow+0x50/0x84 fs/namei.c:1935 but task is already holding lock: ffff0000c6d99880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1b0/0x3b8 fs/kernfs/file.c:336 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x1078 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 kernfs_seq_start+0x54/0x164 fs/kernfs/file.c:165 seq_read_iter+0x340/0xbe8 fs/seq_file.c:226 kernfs_fop_read_iter+0x13c/0x414 fs/kernfs/file.c:290 __kernel_read+0x3b4/0x7cc fs/read_write.c:532 integrity_kernel_read+0x9c/0xe4 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline] ima_calc_file_hash+0x34c/0x5cc security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x420/0x874 security/integrity/ima/ima_api.c:300 process_measurement+0xe64/0x17d4 security/integrity/ima/ima_main.c:425 ima_file_check+0xd0/0x11c security/integrity/ima/ima_main.c:685 security_file_post_open+0x94/0x280 security/security.c:2755 do_open fs/namei.c:4839 [inline] path_openat+0x10d0/0x18f0 fs/namei.c:5000 do_file_open+0x1c8/0x2e8 fs/namei.c:5029 do_sys_openat2+0x114/0x1e8 fs/open.c:1417 do_sys_open+0xb0/0xe0 fs/open.c:1423 __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __arm64_sys_openat+0xa8/0xc4 fs/open.c:1434 __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+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 -> #3 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x1078 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 seq_read_iter+0xb0/0xbe8 fs/seq_file.c:183 kernfs_fop_read_iter+0x13c/0x414 fs/kernfs/file.c:290 __kernel_read+0x3b4/0x7cc fs/read_write.c:532 integrity_kernel_read+0x9c/0xe4 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline] ima_calc_file_hash+0x34c/0x5cc security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x420/0x874 security/integrity/ima/ima_api.c:300 process_measurement+0xe64/0x17d4 security/integrity/ima/ima_main.c:425 ima_file_check+0xd0/0x11c security/integrity/ima/ima_main.c:685 security_file_post_open+0x94/0x280 security/security.c:2755 do_open fs/namei.c:4839 [inline] path_openat+0x10d0/0x18f0 fs/namei.c:5000 do_file_open+0x1c8/0x2e8 fs/namei.c:5029 do_sys_openat2+0x114/0x1e8 fs/open.c:1417 do_sys_open+0xb0/0xe0 fs/open.c:1423 __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __arm64_sys_openat+0xa8/0xc4 fs/open.c:1434 __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+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 -> #2 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x1078 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 process_measurement+0x5b4/0x17d4 security/integrity/ima/ima_main.c:319 ima_file_check+0xd0/0x11c security/integrity/ima/ima_main.c:685 security_file_post_open+0x94/0x280 security/security.c:2755 do_open fs/namei.c:4839 [inline] path_openat+0x10d0/0x18f0 fs/namei.c:5000 do_file_open+0x1c8/0x2e8 fs/namei.c:5029 do_sys_openat2+0x114/0x1e8 fs/open.c:1417 do_sys_open+0xb0/0xe0 fs/open.c:1423 __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __arm64_sys_openat+0xa8/0xc4 fs/open.c:1434 __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+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 -> #1 (sb_writers#5){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write+0x5c/0x208 include/linux/fs/super.h:125 mnt_want_write+0x44/0x9c fs/namespace.c:494 ovl_want_write+0x90/0xa0 fs/overlayfs/util.c:38 ovl_fileattr_set+0xe4/0x268 fs/overlayfs/inode.c:665 vfs_fileattr_set+0x6a8/0x908 fs/file_attr.c:301 ioctl_setflags+0x1e0/0x270 fs/file_attr.c:337 do_vfs_ioctl+0x884/0x1688 fs/ioctl.c:560 __do_sys_ioctl fs/ioctl.c:595 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0xec/0x1cc fs/ioctl.c:583 __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+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 -> #0 (&ovl_i_mutex_dir_key[depth]#2){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1660/0x2b08 kernel/locking/lockdep.c:5288 lock_acquire+0x13c/0x320 kernel/locking/lockdep.c:5942 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+0xc0/0x264 block/bdev.c:1268 resume_store+0x120/0x3e4 kernel/power/hibernate.c:1278 kobj_attr_store+0x6c/0x90 lib/kobject.c:842 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x51c/0xa0c fs/read_write.c:687 ksys_write+0x12c/0x228 fs/read_write.c:739 __do_sys_write fs/read_write.c:750 [inline] __se_sys_write fs/read_write.c:747 [inline] __arm64_sys_write+0x84/0x98 fs/read_write.c:747 __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+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 other info that might help us debug this: Chain exists of: &ovl_i_mutex_dir_key[depth]#2 --> &p->lock --> &of->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&of->mutex); lock(&p->lock); lock(&of->mutex); rlock(&ovl_i_mutex_dir_key[depth]#2); *** DEADLOCK *** locks held by syz.4.1160/9782: 4, last CPU#0: #0: ffff0000d1c09b30 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x100/0x144 fs/file.c:1259 #1: ffff0000d13fa460 (sb_writers#6){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline] #1: ffff0000d13fa460 (sb_writers#6){.+.+}-{0:0}, at: vfs_write+0x248/0xa0c fs/read_write.c:683 #2: ffff0000c6d99880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1b0/0x3b8 fs/kernfs/file.c:336 #3: ffff0000c1cfff08 (kn->active#72){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #3: ffff0000c1cfff08 (kn->active#72){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1f0/0x3b8 fs/kernfs/file.c:337 stack backtrace: CPU: 0 UID: 0 PID: 9782 Comm: syz.4.1160 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026 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:2087 check_noncircular+0x158/0x174 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1660/0x2b08 kernel/locking/lockdep.c:5288 lock_acquire+0x13c/0x320 kernel/locking/lockdep.c:5942 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+0xc0/0x264 block/bdev.c:1268 resume_store+0x120/0x3e4 kernel/power/hibernate.c:1278 kobj_attr_store+0x6c/0x90 lib/kobject.c:842 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x51c/0xa0c fs/read_write.c:687 ksys_write+0x12c/0x228 fs/read_write.c:739 __do_sys_write fs/read_write.c:750 [inline] __se_sys_write fs/read_write.c:747 [inline] __arm64_sys_write+0x84/0x98 fs/read_write.c:747 __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+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 block device autoloading is deprecated and will be removed. PM: Image not found (code -22)