======================================================
WARNING: possible circular locking dependency detected
5.1.0-rc6+ #84 Not tainted
------------------------------------------------------
syz-executor.1/13899 is trying to acquire lock:
00000000993b20b4 (&acct->lock#2){+.+.}, at: acct_pin_kill+0x27/0x100 kernel/acct.c:173
but task is already holding lock:
000000007de26caf (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1621 [inline]
000000007de26caf (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:358
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (sb_writers#3){.+.+}:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
percpu_down_read include/linux/percpu-rwsem.h:36 [inline]
__sb_start_write+0x20b/0x360 fs/super.c:1613
file_start_write include/linux/fs.h:2825 [inline]
ovl_write_iter+0x91b/0xc20 fs/overlayfs/file.c:243
call_write_iter include/linux/fs.h:1866 [inline]
new_sync_write+0x4c7/0x760 fs/read_write.c:474
__vfs_write+0xe4/0x110 fs/read_write.c:487
vfs_write+0x20c/0x580 fs/read_write.c:549
ksys_write+0x14f/0x2d0 fs/read_write.c:599
__do_sys_write fs/read_write.c:611 [inline]
__se_sys_write fs/read_write.c:608 [inline]
__x64_sys_write+0x73/0xb0 fs/read_write.c:608
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (&ovl_i_mutex_key[depth]){+.+.}:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
down_write+0x38/0x90 kernel/locking/rwsem.c:70
inode_lock include/linux/fs.h:772 [inline]
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231
call_write_iter include/linux/fs.h:1866 [inline]
new_sync_write+0x4c7/0x760 fs/read_write.c:474
__vfs_write+0xe4/0x110 fs/read_write.c:487
__kernel_write+0x110/0x3b0 fs/read_write.c:506
do_acct_process+0xd37/0x1150 kernel/acct.c:520
acct_pin_kill+0x2f/0x100 kernel/acct.c:174
pin_kill+0x18f/0x860 fs/fs_pin.c:50
acct_on+0x574/0x790 kernel/acct.c:254
__do_sys_acct kernel/acct.c:286 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xae/0x200 kernel/acct.c:273
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (&acct->lock#2){+.+.}:
check_prevs_add kernel/locking/lockdep.c:2333 [inline]
validate_chain kernel/locking/lockdep.c:2714 [inline]
__lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__mutex_lock_common kernel/locking/mutex.c:925 [inline]
__mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
acct_pin_kill+0x27/0x100 kernel/acct.c:173
pin_kill+0x18f/0x860 fs/fs_pin.c:50
acct_on+0x574/0x790 kernel/acct.c:254
__do_sys_acct kernel/acct.c:286 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xae/0x200 kernel/acct.c:273
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
&acct->lock#2 --> &ovl_i_mutex_key[depth] --> sb_writers#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sb_writers#3);
lock(&ovl_i_mutex_key[depth]);
lock(sb_writers#3);
lock(&acct->lock#2);
*** DEADLOCK ***
2 locks held by syz-executor.1/13899:
#0: 00000000db148cd3 (acct_on_mutex){+.+.}, at: __do_sys_acct kernel/acct.c:285 [inline]
#0: 00000000db148cd3 (acct_on_mutex){+.+.}, at: __se_sys_acct kernel/acct.c:273 [inline]
#0: 00000000db148cd3 (acct_on_mutex){+.+.}, at: __x64_sys_acct+0xa6/0x200 kernel/acct.c:273
#1: 000000007de26caf (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1621 [inline]
#1: 000000007de26caf (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:358
stack backtrace:
CPU: 1 PID: 13899 Comm: syz-executor.1 Not tainted 5.1.0-rc6+ #84
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+0x172/0x1f0 lib/dump_stack.c:113
print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1571
check_prev_add.constprop.0+0xf11/0x23c0 kernel/locking/lockdep.c:2220
check_prevs_add kernel/locking/lockdep.c:2333 [inline]
validate_chain kernel/locking/lockdep.c:2714 [inline]
__lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__mutex_lock_common kernel/locking/mutex.c:925 [inline]
__mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
acct_pin_kill+0x27/0x100 kernel/acct.c:173
pin_kill+0x18f/0x860 fs/fs_pin.c:50
acct_on+0x574/0x790 kernel/acct.c:254
__do_sys_acct kernel/acct.c:286 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xae/0x200 kernel/acct.c:273
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458d99
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f44d01bcc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000458d99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000
RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f44d01bd6d4
R13: 00000000004becb2 R14: 00000000004cfa30 R15: 00000000ffffffff
Process accounting resumed
Process accounting resumed