NILFS (loop5): couldn't find nilfs on the device
======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/26860 is trying to acquire lock:
0000000024b51587 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting fs/proc/base.c:2750 [inline]
0000000024b51587 (&sig->cred_guard_mutex){+.+.}, at: proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793

but task is already holding lock:
0000000025546470 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&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

-> #2 (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
       ovl_posix_acl_xattr_set+0x347/0x9a0 fs/overlayfs/super.c:917
       __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

-> #1 (&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

-> #0 (&sig->cred_guard_mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:937 [inline]
       __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
       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
       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

other info that might help us debug this:

Chain exists of:
  &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->lock);
                               lock(sb_writers#3);
                               lock(&p->lock);
  lock(&sig->cred_guard_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor.1/26860:
 #0: 0000000025546470 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164

stack backtrace:
CPU: 0 PID: 26860 Comm: syz-executor.1 Not tainted 4.19.211-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
 __mutex_lock_common kernel/locking/mutex.c:937 [inline]
 __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
 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
 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
RIP: 0033:0x7f6e14745ae9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6e11cbb188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f6e14858f60 RCX: 00007f6e14745ae9
RDX: 0000000000000332 RSI: 00000000200017c0 RDI: 0000000000000005
RBP: 00007f6e1479ff6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdbe54c0bf R14: 00007f6e11cbb300 R15: 0000000000022000
tmpfs: No value for mount option 'bpf'
overlayfs: unrecognized mount option "upperdir	./bu–" or missing value
IPVS: ftp: loaded support on port[0] = 21
attempt to access beyond end of device
loop1: rw=1, want=128, limit=16
audit: type=1804 audit(1637021348.681:1823): pid=26935 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.2" name="/root/syzkaller-testdir083069721/syzkaller.VKacrN/49/file1/bus" dev="loop2" ino=183 res=1
audit: type=1804 audit(1637021348.771:1824): pid=26943 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.2" name="/root/syzkaller-testdir083069721/syzkaller.VKacrN/49/file1/bus" dev="loop2" ino=183 res=1
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered disabled state
device ip6gretap0 entered promiscuous mode
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered forwarding state
device ip6gretap0 left promiscuous mode
bridge0: port 3(ip6gretap0) entered disabled state
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered disabled state
device ip6gretap0 entered promiscuous mode
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered forwarding state
device ip6gretap0 left promiscuous mode
bridge0: port 3(ip6gretap0) entered disabled state
serio: Serial port pty25
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered disabled state
device ip6gretap0 entered promiscuous mode
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered forwarding state
device ip6gretap0 left promiscuous mode
bridge0: port 3(ip6gretap0) entered disabled state
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered disabled state
device ip6gretap0 entered promiscuous mode
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered forwarding state
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
device ip6gretap0 left promiscuous mode
bridge0: port 3(ip6gretap0) entered disabled state
device wlan1 entered promiscuous mode
device batadv0 entered promiscuous mode
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered disabled state
device ip6gretap0 entered promiscuous mode
bridge0: port 3(ip6gretap0) entered blocking state
bridge0: port 3(ip6gretap0) entered forwarding state
device ip6gretap0 left promiscuous mode
bridge0: port 3(ip6gretap0) entered disabled state
mac80211_hwsim hwsim26 wlan1: This device is already a HSR slave.
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
mac80211_hwsim hwsim26 wlan1: This device is already a HSR slave.
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.
mac80211_hwsim hwsim26 wlan1: This device is already a HSR slave.
mac80211_hwsim hwsim22 wlan1: This device does not support bridging.