======================================================
WARNING: possible circular locking dependency detected
4.14.189-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/18743 is trying to acquire lock:
(&ovl_i_mutex_key[depth]){+.+.}, at: [<ffffffff818e639a>] inode_lock include/linux/fs.h:719 [inline]
(&ovl_i_mutex_key[depth]){+.+.}, at: [<ffffffff818e639a>] bprm_fill_uid fs/exec.c:1524 [inline]
(&ovl_i_mutex_key[depth]){+.+.}, at: [<ffffffff818e639a>] prepare_binprm+0x31a/0x7e0 fs/exec.c:1559
but task is already holding lock:
(&sig->cred_guard_mutex){+.+.}, at: [<ffffffff818eac69>] prepare_bprm_creds fs/exec.c:1391 [inline]
(&sig->cred_guard_mutex){+.+.}, at: [<ffffffff818eac69>] do_execveat_common+0x319/0x1f30 fs/exec.c:1735
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:756 [inline]
__mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
lock_trace fs/proc/base.c:407 [inline]
proc_pid_stack+0x13f/0x2f0 fs/proc/base.c:457
proc_single_show+0xe7/0x150 fs/proc/base.c:761
traverse+0x306/0x850 fs/seq_file.c:111
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
seq_read+0x94b/0x1120 fs/seq_file.c:192
do_loop_readv_writev fs/read_write.c:695 [inline]
do_loop_readv_writev fs/read_write.c:682 [inline]
do_iter_read+0x3eb/0x5b0 fs/read_write.c:919
vfs_readv+0xc8/0x120 fs/read_write.c:981
do_preadv fs/read_write.c:1065 [inline]
SYSC_preadv fs/read_write.c:1115 [inline]
SyS_preadv+0x15a/0x200 fs/read_write.c:1110
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
-> #2 (&p->lock){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
seq_read+0xba/0x1120 fs/seq_file.c:165
proc_reg_read+0xee/0x1a0 fs/proc/inode.c:217
do_loop_readv_writev fs/read_write.c:695 [inline]
do_loop_readv_writev fs/read_write.c:682 [inline]
do_iter_read+0x3eb/0x5b0 fs/read_write.c:919
vfs_readv+0xc8/0x120 fs/read_write.c:981
kernel_readv fs/splice.c:361 [inline]
default_file_splice_read+0x418/0x910 fs/splice.c:416
do_splice_to+0xfb/0x140 fs/splice.c:880
splice_direct_to_actor+0x207/0x730 fs/splice.c:952
do_splice_direct+0x164/0x210 fs/splice.c:1061
do_sendfile+0x47f/0xb30 fs/read_write.c:1441
SYSC_sendfile64 fs/read_write.c:1502 [inline]
SyS_sendfile64+0xff/0x110 fs/read_write.c:1488
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
-> #1 (sb_writers#3){.+.+}:
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+0x19a/0x2e0 fs/super.c:1363
sb_start_write include/linux/fs.h:1549 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:386
ovl_setattr+0x52/0x500 fs/overlayfs/inode.c:38
notify_change+0x56b/0xd10 fs/attr.c:313
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
do_truncate+0xff/0x1a0 fs/open.c:63
handle_truncate fs/namei.c:3010 [inline]
do_last fs/namei.c:3437 [inline]
path_openat+0x1dcc/0x2970 fs/namei.c:3569
do_filp_open+0x179/0x3c0 fs/namei.c:3603
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+0x46/0xbb
-> #0 (&ovl_i_mutex_key[depth]){+.+.}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
down_write+0x34/0x90 kernel/locking/rwsem.c:54
inode_lock include/linux/fs.h:719 [inline]
bprm_fill_uid fs/exec.c:1524 [inline]
prepare_binprm+0x31a/0x7e0 fs/exec.c:1559
do_execveat_common+0xd72/0x1f30 fs/exec.c:1785
do_execve fs/exec.c:1847 [inline]
SYSC_execve fs/exec.c:1928 [inline]
SyS_execve+0x3b/0x50 fs/exec.c:1923
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
other info that might help us debug this:
Chain exists of:
&ovl_i_mutex_key[depth] --> &p->lock --> &sig->cred_guard_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sig->cred_guard_mutex);
lock(&p->lock);
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
lock(&sig->cred_guard_mutex);
lock(&ovl_i_mutex_key[depth]);
*** DEADLOCK ***
1 lock held by syz-executor.4/18743:
#0: (&sig->cred_guard_mutex){+.+.}, at: [<ffffffff818eac69>] prepare_bprm_creds fs/exec.c:1391 [inline]
#0: (&sig->cred_guard_mutex){+.+.}, at: [<ffffffff818eac69>] do_execveat_common+0x319/0x1f30 fs/exec.c:1735
stack backtrace:
CPU: 0 PID: 18743 Comm: syz-executor.4 Not tainted 4.14.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 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
down_write+0x34/0x90 kernel/locking/rwsem.c:54
inode_lock include/linux/fs.h:719 [inline]
bprm_fill_uid fs/exec.c:1524 [inline]
prepare_binprm+0x31a/0x7e0 fs/exec.c:1559
do_execveat_common+0xd72/0x1f30 fs/exec.c:1785
do_execve fs/exec.c:1847 [inline]
SYSC_execve fs/exec.c:1928 [inline]
SyS_execve+0x3b/0x50 fs/exec.c:1923
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45c1f9
RSP: 002b:00007ff23a97dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 0000000000002c00 RCX: 000000000045c1f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffc16253f4f R14: 00007ff23a97e9c0 R15: 000000000078bf0c
ptrace attach of "/root/syz-executor.4"[18787] was attempted by "/root/syz-executor.4"[18791]
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
audit: type=1804 audit(1595606986.261:148): pid=18857 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir591901974/syzkaller.QhSH9w/1877/bus" dev="sda1" ino=16183 res=1
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
audit: type=1804 audit(1595606987.061:149): pid=18915 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="ToMToU" comm="syz-executor.4" name="/root/syzkaller-testdir591901974/syzkaller.QhSH9w/1877/bus" dev="sda1" ino=16183 res=1
audit: type=1804 audit(1595606987.121:150): pid=18917 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir591901974/syzkaller.QhSH9w/1877/bus" dev="sda1" ino=16183 res=1
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
audit: type=1804 audit(1595606989.301:151): pid=18921 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir591901974/syzkaller.QhSH9w/1878/bus" dev="sda1" ino=16389 res=1
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.