======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/5799 is trying to acquire lock:
00000000689653b9 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164

but task is already holding lock:
00000000d8ba5b1c (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline]
00000000d8ba5b1c (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 fs/read_write.c:1446

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (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

-> #2 (&ovl_i_mutex_dir_key[depth]#2){++++}:
       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
netlink: 560 bytes leftover after parsing attributes in process `syz-executor.3'.
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #1 (&sig->cred_guard_mutex){+.+.}:
       do_io_accounting fs/proc/base.c:2750 [inline]
       proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793
       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

-> #0 (&p->lock){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:937 [inline]
       __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
       seq_read+0x6b/0x11c0 fs/seq_file.c:164
       kernfs_fop_read+0xe9/0x550 fs/kernfs/file.c:252
       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

other info that might help us debug this:

Chain exists of:
  &p->lock --> &ovl_i_mutex_dir_key[depth]#2 --> sb_writers#3

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#3);
                               lock(&ovl_i_mutex_dir_key[depth]#2);
                               lock(sb_writers#3);
  lock(&p->lock);

 *** DEADLOCK ***

1 lock held by syz-executor.0/5799:
 #0: 00000000d8ba5b1c (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline]
 #0: 00000000d8ba5b1c (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 fs/read_write.c:1446

stack backtrace:
CPU: 1 PID: 5799 Comm: syz-executor.0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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
 __mutex_lock_common kernel/locking/mutex.c:937 [inline]
 __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
 seq_read+0x6b/0x11c0 fs/seq_file.c:164
 kernfs_fop_read+0xe9/0x550 fs/kernfs/file.c:252
 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
RIP: 0033:0x7f42c65710a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007f42c4ae3168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f42c6690f80 RCX: 00007f42c65710a9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007f42c65ccae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdbc0189bf R14: 00007f42c4ae3300 R15: 0000000000022000
netlink: 68 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 68 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 68 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 68 bytes leftover after parsing attributes in process `syz-executor.0'.
9pnet_virtio: no channels available for device syz
netlink: 372 bytes leftover after parsing attributes in process `syz-executor.1'.
autofs4:pid:6148:check_dev_ioctl_version: ioctl control interface version mismatch: kernel(1.1), user(2181038081.426396096), cmd(0xc0189373)
autofs4:pid:6148:validate_dev_ioctl: invalid device control module version supplied for cmd(0xc0189373)
9pnet: Could not find request transport: x
Unknown ioctl 1075883638
Unknown ioctl -805268418
Unknown ioctl 1075883638