======================================================
WARNING: possible circular locking dependency detected
4.14.97+ #4 Not tainted
------------------------------------------------------
syz-executor5/6504 is trying to acquire lock:
 (&p->lock){+.+.}, at: [<ffffffffbb1ccd6d>] seq_read+0xcd/0x1180 fs/seq_file.c:165

but task is already holding lock:
 (&sig->cred_guard_mutex){+.+.}, at: [<ffffffffbb16c741>] prepare_bprm_creds+0x51/0x110 fs/exec.c:1389

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sig->cred_guard_mutex){+.+.}:

-> #0 (&p->lock){+.+.}:

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz-executor5/6504:
 #0:  (&sig->cred_guard_mutex){+.+.}, at: [<ffffffffbb16c741>] prepare_bprm_creds+0x51/0x110 fs/exec.c:1389

stack backtrace:
CPU: 0 PID: 6504 Comm: syz-executor5 Not tainted 4.14.97+ #4
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1258
binder: 6529:6532 unknown command 570450701
binder: 6529:6532 ioctl c0306201 20000180 returned -22
binder: 6529:6541 ioctl 5419 20000200 returned -22
binder: 6529:6532 unknown command 570450701
binder: 6529:6541 ioctl 5419 20000200 returned -22
binder: 6529:6532 ioctl c0306201 20000180 returned -22
binder: 6562:6566 unknown command 570450701
binder: 6558:6569 unknown command 570450701
binder: 6562:6566 ioctl c0306201 20000180 returned -22
binder: 6558:6569 ioctl c0306201 20000180 returned -22
binder: 6560:6567 unknown command 570450701
binder: 6562:6566 ioctl 5419 20000200 returned -22
binder: 6560:6567 ioctl c0306201 20000180 returned -22
binder: 6558:6569 ioctl 5419 20000200 returned -22
binder: 6560:6567 ioctl 5419 20000200 returned -22
binder: 6587:6592 unknown command 570450701
binder: 6587:6592 ioctl c0306201 20000180 returned -22
binder: 6601:6603 unknown command 570450701
binder: 6587:6604 ioctl 5419 20000200 returned -22
binder: 6601:6603 ioctl c0306201 20000180 returned -22
binder: 6601:6612 ioctl 5419 20000200 returned -22
binder: 6619:6622 unknown command 570450701
binder: 6619:6622 ioctl c0306201 20000180 returned -22
binder: 6619:6631 ioctl 5419 20000200 returned -22
binder: 6633:6644 unknown command 570450701
binder: 6633:6644 ioctl c0306201 20000180 returned -22
binder: 6633:6655 ioctl 5419 20000200 returned -22
binder: 6657:6659 unknown command 570450701
binder: 6657:6659 ioctl c0306201 20000180 returned -22
binder: 6657:6659 ioctl 5419 20000200 returned -22
binder: 6670:6673 unknown command 570450701
binder: 6670:6673 ioctl c0306201 20000180 returned -22
binder: 6670:6673 ioctl 5419 20000200 returned -22
binder: 6691:6693 unknown command 570450701
binder: 6691:6693 ioctl c0306201 20000180 returned -22
binder: 6687:6698 unknown command 570450701
binder: 6687:6698 ioctl c0306201 20000180 returned -22
binder: 6691:6693 ioctl 5419 20000200 returned -22
binder: 6687:6698 ioctl 5419 20000200 returned -22
binder: 6717:6719 unknown command 570450701
binder: 6716:6720 unknown command 570450701
binder: 6717:6719 ioctl c0306201 20000180 returned -22
binder: 6716:6720 ioctl c0306201 20000180 returned -22
binder: 6717:6719 ioctl 5419 20000200 returned -22
binder: 6722:6724 unknown command 570450701
binder: 6716:6720 ioctl 5419 20000200 returned -22
binder: 6722:6724 ioctl c0306201 20000180 returned -22
binder: 6722:6724 ioctl 5419 20000200 returned -22
binder: 6732:6738 unknown command 570450701
binder: 6729:6739 unknown command 570450701
binder: 6732:6738 ioctl c0306201 20000180 returned -22
binder: 6729:6739 ioctl c0306201 20000180 returned -22
binder: 6754:6758 unknown command 570450701
binder: 6754:6758 ioctl c0306201 20000180 returned -22
binder: 6770:6775 unknown command 570450701
binder: 6770:6775 ioctl c0306201 20000180 returned -22
binder: 6809:6812 unknown command 570450701
binder: 6809:6812 ioctl c0306201 20000180 returned -22
binder: 6909:6913 unknown command 570450701
binder: 6909:6913 ioctl c0306201 20000180 returned -22
binder: 6949:6954 unknown command 570450701
binder: 6949:6954 ioctl c0306201 20000180 returned -22
binder: 6964:6969 unknown command 570450701
binder: 6964:6969 ioctl c0306201 20000180 returned -22
binder: 7085:7092 ioctl c0306201 0 returned -14
binder: 7110:7112 ioctl c0306201 0 returned -14