======================================================
WARNING: possible circular locking dependency detected
4.14.97+ #1 Not tainted
------------------------------------------------------
syz-executor4/8232 is trying to acquire lock:
(&p->lock){+.+.}, at: [<ffffffffb99ccd6d>] seq_read+0xcd/0x1180 fs/seq_file.c:165
but task is already holding lock:
(&pipe->mutex/1){+.+.}, at: [<ffffffffb996f128>] pipe_lock_nested fs/pipe.c:67 [inline]
(&pipe->mutex/1){+.+.}, at: [<ffffffffb996f128>] pipe_lock+0x58/0x70 fs/pipe.c:75
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&pipe->mutex/1){+.+.}:
-> #1 (&sig->cred_guard_mutex){+.+.}:
-> #0 (&p->lock){+.+.}:
other info that might help us debug this:
Chain exists of:
&p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&pipe->mutex/1);
lock(&sig->cred_guard_mutex);
lock(&pipe->mutex/1);
lock(&p->lock);
*** DEADLOCK ***
1 lock held by syz-executor4/8232:
#0: (&pipe->mutex/1){+.+.}, at: [<ffffffffb996f128>] pipe_lock_nested fs/pipe.c:67 [inline]
#0: (&pipe->mutex/1){+.+.}, at: [<ffffffffb996f128>] pipe_lock+0x58/0x70 fs/pipe.c:75
stack backtrace:
CPU: 0 PID: 8232 Comm: syz-executor4 Not tainted 4.14.97+ #1
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: 8190:8217 ioctl c0306201 0 returned -14
binder: BINDER_SET_CONTEXT_MGR already set
binder: 8190:8212 ioctl 40046207 0 returned -16
binder_alloc: 8190: binder_alloc_buf, no vma
binder: 8190:8240 transaction failed 29189/-3, size 24-8 line 3135
binder: 8190:8217 Release 1 refcount change on invalid ref 1 ret -22
binder: 8190:8212 unknown command 262144
binder: 8190:8212 ioctl c0306201 200002c0 returned -22
binder: send failed reply for transaction 31 to 8190:8196
binder: undelivered TRANSACTION_COMPLETE
binder: undelivered TRANSACTION_ERROR: 29189
connect: ipv4 mapped
connect: ipv4 mapped