======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/11178 is trying to acquire lock:
0000000019ec1060 (&ovl_i_mutex_dir_key[depth]){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
0000000019ec1060 (&ovl_i_mutex_dir_key[depth]){++++}, at: do_last fs/namei.c:3326 [inline]
0000000019ec1060 (&ovl_i_mutex_dir_key[depth]){++++}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537

but task is already holding lock:
00000000f3eca0a3 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1419 [inline]
00000000f3eca0a3 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file+0x38c/0x2360 fs/exec.c:1762

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&sig->cred_guard_mutex){+.+.}:
       do_io_accounting fs/proc/base.c:2750 [inline]
       proc_tgid_io_accounting+0x1cf/0x7f0 fs/proc/base.c:2799
       proc_single_show+0xeb/0x170 fs/proc/base.c:755
       seq_read+0x4e0/0x11c0 fs/seq_file.c:232
       __vfs_read+0xf7/0x750 fs/read_write.c:416
       vfs_read+0x194/0x3c0 fs/read_write.c:452
       ksys_read+0x12b/0x2a0 fs/read_write.c:579
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #2 (&p->lock){+.+.}:
       seq_read+0x6b/0x11c0 fs/seq_file.c:164
       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

-> #1 (sb_writers#3){.+.+}:
       sb_start_write include/linux/fs.h:1579 [inline]
       mnt_want_write+0x3a/0xb0 fs/namespace.c:360
       ovl_xattr_set+0x53/0x600 fs/overlayfs/inode.c:338
       __vfs_setxattr+0x10e/0x170 fs/xattr.c:149
       __vfs_setxattr_noperm+0x11a/0x420 fs/xattr.c:180
       __vfs_setxattr_locked+0x176/0x250 fs/xattr.c:238
       vfs_setxattr+0xe5/0x270 fs/xattr.c:255
       setxattr+0x23d/0x330 fs/xattr.c:520
       path_setxattr+0x170/0x190 fs/xattr.c:539
       __do_sys_lsetxattr fs/xattr.c:561 [inline]
       __se_sys_lsetxattr fs/xattr.c:557 [inline]
       __x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:557
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (&ovl_i_mutex_dir_key[depth]){++++}:
       down_read+0x36/0x80 kernel/locking/rwsem.c:24
       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

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.5/11178:
 #0: 00000000f3eca0a3 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1419 [inline]
 #0: 00000000f3eca0a3 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file+0x38c/0x2360 fs/exec.c:1762

stack backtrace:
CPU: 0 PID: 11178 Comm: syz-executor.5 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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
 down_read+0x36/0x80 kernel/locking/rwsem.c:24
 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
RIP: 0033:0x7fc9e9b53279
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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:00007fc9e8423168 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007fc9e9c66390 RCX: 00007fc9e9b53279
RDX: 0000000020000500 RSI: 00000000200003c0 RDI: 0000000020000180
RBP: 00007fc9e9bad189 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe26d2298f R14: 00007fc9e8423300 R15: 0000000000022000
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
overlayfs: unrecognized mount option "rdir=.:f" or missing value
overlayfs: failed to resolve './file1': -2
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: failed to resolve './file1': -2
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
ieee802154 phy1 wpan1: encryption failed: -22
overlayfs: unrecognized mount option "lo’erdir=.:file0" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: unrecognized mount option "lo’erdir=.:file0" or missing value
overlayfs: failed to resolve './file0': -2
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: failed to resolve './file1': -2
overlayfs: unrecognized mount option "nowerdir=.:file0“ÆZE{}" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: unrecognized mount option "nowerdir=.:file0“ÆZE{}" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: unrecognized mount option "nowerdir=.:file0“ÆZE{}" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: failed to resolve './file1': -2
overlayfs: overlapping lowerdir path
overlayfs: failed to resolve './file1': -2
overlayfs: failed to resolve './file1': -2
overlayfs: unrecognized mount option "workdQèÅ–Y»" or missing value
overlayfs: unrecognized mount option "+"e|_ˆ}" or missing value
overlayfs: unrecognized mount option "+"e|_ˆ}" or missing value
nla_parse: 11 callbacks suppressed
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
overlayfs: unrecognized mount option "+"e|_ˆ}" or missing value
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: overlapping lowerdir path
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
overlayfs: failed to resolve './file1': -2
overlayfs: unrecognized mount option "lowerdUr0./file0" or missing value
overlayfs: unrecognized mount option "lowerdUr0./file0" or missing value
overlayfs: unrecognized mount option "lowerdUr0./file0" or missing value