======================================================
WARNING: possible circular locking dependency detected
4.14.307-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/9534 is trying to acquire lock:
(sb_writers#3){.+.+}, at: [<ffffffff818e203a>] sb_start_write include/linux/fs.h:1551 [inline]
(sb_writers#3){.+.+}, at: [<ffffffff818e203a>] mnt_want_write+0x3a/0xb0 fs/namespace.c:386
but task is already holding lock:
(&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818a4a42>] inode_lock include/linux/fs.h:719 [inline]
(&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818a4a42>] do_last fs/namei.c:3331 [inline]
(&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818a4a42>] path_openat+0xde2/0x2970 fs/namei.c:3571
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}:
down_write_killable+0x37/0xb0 kernel/locking/rwsem.c:68
iterate_dir+0x387/0x5e0 fs/readdir.c:43
ovl_dir_read fs/overlayfs/readdir.c:306 [inline]
ovl_dir_read_merged+0x2c5/0x430 fs/overlayfs/readdir.c:365
ovl_check_empty_dir+0x6e/0x200 fs/overlayfs/readdir.c:870
ovl_check_empty_and_clear+0x72/0xe0 fs/overlayfs/dir.c:306
ovl_rename+0x57d/0xe50 fs/overlayfs/dir.c:959
vfs_rename+0x560/0x1820 fs/namei.c:4498
SYSC_renameat2 fs/namei.c:4646 [inline]
SyS_renameat2+0x95b/0xad0 fs/namei.c:4535
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
-> #0 (sb_writers#3){.+.+}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
__sb_start_write+0x64/0x260 fs/super.c:1342
sb_start_write include/linux/fs.h:1551 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:386
ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538
lookup_open+0x77a/0x1750 fs/namei.c:3241
do_last fs/namei.c:3334 [inline]
path_openat+0xe08/0x2970 fs/namei.c:3571
do_filp_open+0x179/0x3c0 fs/namei.c:3605
do_sys_open+0x296/0x410 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ovl_i_mutex_dir_key[depth]#2);
lock(sb_writers#3);
lock(&ovl_i_mutex_dir_key[depth]#2);
lock(sb_writers#3);
*** DEADLOCK ***
2 locks held by syz-executor.5/9534:
#0: (sb_writers#13){.+.+}, at: [<ffffffff818e203a>] sb_start_write include/linux/fs.h:1551 [inline]
#0: (sb_writers#13){.+.+}, at: [<ffffffff818e203a>] mnt_want_write+0x3a/0xb0 fs/namespace.c:386
#1: (&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818a4a42>] inode_lock include/linux/fs.h:719 [inline]
#1: (&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818a4a42>] do_last fs/namei.c:3331 [inline]
#1: (&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818a4a42>] path_openat+0xde2/0x2970 fs/namei.c:3571
stack backtrace:
CPU: 0 PID: 9534 Comm: syz-executor.5 Not tainted 4.14.307-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x281 lib/dump_stack.c:58
print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1905 [inline]
check_prevs_add kernel/locking/lockdep.c:2022 [inline]
validate_chain kernel/locking/lockdep.c:2464 [inline]
__lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
__sb_start_write+0x64/0x260 fs/super.c:1342
sb_start_write include/linux/fs.h:1551 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:386
ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538
lookup_open+0x77a/0x1750 fs/namei.c:3241
do_last fs/namei.c:3334 [inline]
path_openat+0xe08/0x2970 fs/namei.c:3571
do_filp_open+0x179/0x3c0 fs/namei.c:3605
do_sys_open+0x296/0x410 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f466702d0f9
RSP: 002b:00007f466559f168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f466714cf80 RCX: 00007f466702d0f9
RDX: 000000000000275a RSI: 0000000020000240 RDI: ffffffffffffff9c
RBP: 00007f4667088ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffcdb401af R14: 00007f466559f300 R15: 0000000000022000
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.