======================================================
WARNING: possible circular locking dependency detected
5.4.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/31649 is trying to acquire lock:
ffff88801d2bd1e0 (&ovl_i_mutex_dir_key[depth]){++++}, at: inode_lock_shared include/linux/fs.h:801 [inline]
ffff88801d2bd1e0 (&ovl_i_mutex_dir_key[depth]){++++}, at: do_last fs/namei.c:3317 [inline]
ffff88801d2bd1e0 (&ovl_i_mutex_dir_key[depth]){++++}, at: path_openat+0x1e91/0x4710 fs/namei.c:3529
but task is already holding lock:
ffff88801d890790 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1408 [inline]
ffff88801d890790 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x376/0x22b0 fs/exec.c:1753
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&sig->cred_guard_mutex){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:959 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106
mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:1136
lock_trace+0x4a/0xe0 fs/proc/base.c:406
proc_pid_syscall+0x8a/0x220 fs/proc/base.c:635
proc_single_show+0xfd/0x1c0 fs/proc/base.c:756
seq_read+0x4ca/0x1110 fs/seq_file.c:229
do_loop_readv_writev fs/read_write.c:714 [inline]
do_loop_readv_writev fs/read_write.c:701 [inline]
do_iter_read+0x4a4/0x660 fs/read_write.c:935
vfs_readv+0xf0/0x160 fs/read_write.c:997
kernel_readv fs/splice.c:365 [inline]
default_file_splice_read+0x4fb/0xa20 fs/splice.c:422
do_splice_to+0x127/0x180 fs/splice.c:890
splice_direct_to_actor+0x320/0xa30 fs/splice.c:969
do_splice_direct+0x1da/0x2a0 fs/splice.c:1078
do_sendfile+0x597/0xd00 fs/read_write.c:1464
__do_sys_sendfile64 fs/read_write.c:1525 [inline]
__se_sys_sendfile64 fs/read_write.c:1511 [inline]
__x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #2 (&p->lock){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:959 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121
seq_read+0x71/0x1110 fs/seq_file.c:161
proc_reg_read+0x1fc/0x2c0 fs/proc/inode.c:223
do_loop_readv_writev fs/read_write.c:714 [inline]
do_loop_readv_writev fs/read_write.c:701 [inline]
do_iter_read+0x4a4/0x660 fs/read_write.c:935
vfs_readv+0xf0/0x160 fs/read_write.c:997
kernel_readv fs/splice.c:365 [inline]
default_file_splice_read+0x4fb/0xa20 fs/splice.c:422
do_splice_to+0x127/0x180 fs/splice.c:890
splice_direct_to_actor+0x320/0xa30 fs/splice.c:969
do_splice_direct+0x1da/0x2a0 fs/splice.c:1078
do_sendfile+0x597/0xd00 fs/read_write.c:1464
__do_sys_sendfile64 fs/read_write.c:1525 [inline]
__se_sys_sendfile64 fs/read_write.c:1511 [inline]
__x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (sb_writers#4){.+.+}:
percpu_down_read include/linux/percpu-rwsem.h:40 [inline]
__sb_start_write+0x241/0x460 fs/super.c:1672
sb_start_write include/linux/fs.h:1650 [inline]
mnt_want_write+0x3f/0xc0 fs/namespace.c:354
ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:21
ovl_xattr_set+0x53/0x5b0 fs/overlayfs/inode.c:329
ovl_other_xattr_set+0x39/0x50 fs/overlayfs/super.c:948
__vfs_setxattr+0x11f/0x180 fs/xattr.c:150
__vfs_setxattr_noperm+0x11c/0x410 fs/xattr.c:181
vfs_setxattr+0xda/0x100 fs/xattr.c:224
setxattr+0x26f/0x380 fs/xattr.c:451
path_setxattr+0x197/0x1b0 fs/xattr.c:470
__do_sys_lsetxattr fs/xattr.c:492 [inline]
__se_sys_lsetxattr fs/xattr.c:488 [inline]
__x64_sys_lsetxattr+0xc1/0x150 fs/xattr.c:488
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (&ovl_i_mutex_dir_key[depth]){++++}:
check_prev_add kernel/locking/lockdep.c:2476 [inline]
check_prevs_add kernel/locking/lockdep.c:2581 [inline]
validate_chain kernel/locking/lockdep.c:2971 [inline]
__lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
down_read+0x95/0x430 kernel/locking/rwsem.c:1495
inode_lock_shared include/linux/fs.h:801 [inline]
do_last fs/namei.c:3317 [inline]
path_openat+0x1e91/0x4710 fs/namei.c:3529
do_filp_open+0x1a1/0x280 fs/namei.c:3559
do_open_execat+0x137/0x690 fs/exec.c:856
__do_execve_file.isra.0+0x1702/0x22b0 fs/exec.c:1761
do_execveat_common fs/exec.c:1867 [inline]
do_execve fs/exec.c:1884 [inline]
__do_sys_execve fs/exec.c:1960 [inline]
__se_sys_execve fs/exec.c:1955 [inline]
__x64_sys_execve+0x8f/0xc0 fs/exec.c:1955
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
&ovl_i_mutex_dir_key[depth] --> &p->lock --> &sig->cred_guard_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sig->cred_guard_mutex);
lock(&p->lock);
lock(&sig->cred_guard_mutex);
lock(&ovl_i_mutex_dir_key[depth]);
*** DEADLOCK ***
1 lock held by syz-executor.1/31649:
#0: ffff88801d890790 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1408 [inline]
#0: ffff88801d890790 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x376/0x22b0 fs/exec.c:1753
stack backtrace:
CPU: 2 PID: 31649 Comm: syz-executor.1 Not tainted 5.4.0-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1685
check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1809
check_prev_add kernel/locking/lockdep.c:2476 [inline]
check_prevs_add kernel/locking/lockdep.c:2581 [inline]
validate_chain kernel/locking/lockdep.c:2971 [inline]
__lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
down_read+0x95/0x430 kernel/locking/rwsem.c:1495
inode_lock_shared include/linux/fs.h:801 [inline]
do_last fs/namei.c:3317 [inline]
path_openat+0x1e91/0x4710 fs/namei.c:3529
do_filp_open+0x1a1/0x280 fs/namei.c:3559
do_open_execat+0x137/0x690 fs/exec.c:856
__do_execve_file.isra.0+0x1702/0x22b0 fs/exec.c:1761
do_execveat_common fs/exec.c:1867 [inline]
do_execve fs/exec.c:1884 [inline]
__do_sys_execve fs/exec.c:1960 [inline]
__se_sys_execve fs/exec.c:1955 [inline]
__x64_sys_execve+0x8f/0xc0 fs/exec.c:1955
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a759
Code: bd b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f308a31fc88 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 000000000072bf00 RCX: 000000000045a759
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f308a3206d4
R13: 00000000004a7fce R14: 00000000006e8ff0 R15: 00000000ffffffff