====================================================== WARNING: possible circular locking dependency detected 4.14.97+ #1 Not tainted ------------------------------------------------------ syz-executor4/8232 is trying to acquire lock: (&p->lock){+.+.}, at: [] seq_read+0xcd/0x1180 fs/seq_file.c:165 but task is already holding lock: (&pipe->mutex/1){+.+.}, at: [] pipe_lock_nested fs/pipe.c:67 [inline] (&pipe->mutex/1){+.+.}, at: [] 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: [] pipe_lock_nested fs/pipe.c:67 [inline] #0: (&pipe->mutex/1){+.+.}, at: [] 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