hrtimer: interrupt took 46749 ns
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
======================================================
WARNING: possible circular locking dependency detected
4.19.197-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor569/8151 is trying to acquire lock:
000000009be23131 (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
000000009be23131 (sb_writers#3){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360
but task is already holding lock:
0000000006dd582f (&ovl_i_mutex_dir_key[depth]){++++}, at: inode_lock include/linux/fs.h:748 [inline]
0000000006dd582f (&ovl_i_mutex_dir_key[depth]){++++}, at: do_last fs/namei.c:3324 [inline]
0000000006dd582f (&ovl_i_mutex_dir_key[depth]){++++}, at: path_openat+0x1071/0x2df0 fs/namei.c:3537
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&ovl_i_mutex_dir_key[depth]){++++}:
inode_lock_shared include/linux/fs.h:758 [inline]
do_last fs/namei.c:3326 [inline]
path_openat+0x17ec/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #2 (&sig->cred_guard_mutex){+.+.}:
lock_trace fs/proc/base.c:402 [inline]
proc_pid_personality+0x4a/0x170 fs/proc/base.c:2938
proc_single_show+0xeb/0x170 fs/proc/base.c:755
seq_read+0x4be/0x1160 fs/seq_file.c:229
do_loop_readv_writev fs/read_write.c:701 [inline]
do_loop_readv_writev fs/read_write.c:688 [inline]
do_iter_read+0x471/0x630 fs/read_write.c:925
vfs_readv+0xe5/0x150 fs/read_write.c:987
do_preadv fs/read_write.c:1071 [inline]
__do_sys_preadv fs/read_write.c:1121 [inline]
__se_sys_preadv fs/read_write.c:1116 [inline]
__x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (&p->lock){+.+.}:
seq_read+0x6b/0x1160 fs/seq_file.c:161
proc_reg_read+0x1bd/0x2d0 fs/proc/inode.c:231
do_loop_readv_writev fs/read_write.c:701 [inline]
do_loop_readv_writev fs/read_write.c:688 [inline]
do_iter_read+0x471/0x630 fs/read_write.c:925
vfs_readv+0xe5/0x150 fs/read_write.c:987
kernel_readv fs/splice.c:362 [inline]
default_file_splice_read+0x457/0xa00 fs/splice.c:417
do_splice_to+0x10e/0x160 fs/splice.c:881
splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959
do_splice_direct+0x1a7/0x270 fs/splice.c:1068
do_sendfile+0x550/0xc30 fs/read_write.c:1447
__do_sys_sendfile64 fs/read_write.c:1508 [inline]
__se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (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+0x6e/0x2a0 fs/super.c:1366
sb_start_write include/linux/fs.h:1579 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:360
ovl_create_object+0x96/0x290 fs/overlayfs/dir.c:600
lookup_open+0x893/0x1a20 fs/namei.c:3235
do_last fs/namei.c:3327 [inline]
path_openat+0x1094/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_sys_open+0x3b3/0x520 fs/open.c:1085
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
sb_writers#3 --> &sig->cred_guard_mutex --> &ovl_i_mutex_dir_key[depth]
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ovl_i_mutex_dir_key[depth]);
lock(&sig->cred_guard_mutex);
lock(&ovl_i_mutex_dir_key[depth]);
lock(sb_writers#3);
*** DEADLOCK ***
2 locks held by syz-executor569/8151:
#0: 000000006636d5bb (sb_writers#11){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
#0: 000000006636d5bb (sb_writers#11){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360
#1: 0000000006dd582f (&ovl_i_mutex_dir_key[depth]){++++}, at: inode_lock include/linux/fs.h:748 [inline]
#1: 0000000006dd582f (&ovl_i_mutex_dir_key[depth]){++++}, at: do_last fs/namei.c:3324 [inline]
#1: 0000000006dd582f (&ovl_i_mutex_dir_key[depth]){++++}, at: path_openat+0x1071/0x2df0 fs/namei.c:3537
stack backtrace:
CPU: 1 PID: 8151 Comm: syz-executor569 Not tainted 4.19.197-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1866 [inline]
check_prevs_add kernel/locking/lockdep.c:1979 [inline]
validate_chain kernel/locking/lockdep.c:2420 [inline]
__lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
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+0x6e/0x2a0 fs/super.c:1366
sb_start_write include/linux/fs.h:1579 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:360
ovl_create_object+0x96/0x290 fs/overlayfs/dir.c:600
lookup_open+0x893/0x1a20 fs/namei.c:3235
do_last fs/namei.c:3327 [inline]
path_openat+0x1094/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_sys_open+0x3b3/0x520 fs/open.c:1085
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcebac07278 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00000000004cb4e0 RCX: 0000000000446389
RDX: 0000000000000000 RSI: 00000000001612c2 RDI: 0000000020000200
RBP: 000000000049b0a8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd36309a2e
R13: 0073656369766564 R14: 6c616e6f73726570 R15: 00000000004cb4e8
syz-executor569 (8173) used greatest stack depth: 23168 bytes left
syz-executor569 (8460) used greatest stack depth: 23160 bytes left
syz-executor569 (8833) used greatest stack depth: 22888 bytes left