======================================================
WARNING: possible circular locking dependency detected
4.14.129+ #11 Not tainted
------------------------------------------------------
syz-executor.1/13029 is trying to acquire lock:
 (&mm->mmap_sem){++++}, at: [<000000009bd41960>] __might_fault+0xd4/0x1b0 mm/memory.c:4583

but task is already holding lock:
 (&cpuctx_mutex){+.+.}, at: [<0000000089d5ff76>] perf_event_ctx_lock_nested+0x14d/0x2c0 kernel/events/core.c:1240

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&cpuctx_mutex){+.+.}:

-> #4 (pmus_lock){+.+.}:

-> #3 (cpu_hotplug_lock.rw_sem){++++}:

-> #2 (&sb->s_type->i_mutex_key#10){+.+.}:

-> #1 (ashmem_mutex){+.+.}:

-> #0 (&mm->mmap_sem){++++}:

other info that might help us debug this:

Chain exists of:
  &mm->mmap_sem --> pmus_lock --> &cpuctx_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&cpuctx_mutex);
                               lock(pmus_lock);
                               lock(&cpuctx_mutex);
  lock(&mm->mmap_sem);

 *** DEADLOCK ***

1 lock held by syz-executor.1/13029:
 #0:  (&cpuctx_mutex){+.+.}, at: [<0000000089d5ff76>] perf_event_ctx_lock_nested+0x14d/0x2c0 kernel/events/core.c:1240

stack backtrace:
CPU: 1 PID: 13029 Comm: syz-executor.1 Not tainted 4.14.129+ #11
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
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
ip6_tunnel: ip6tnl2 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl2 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl6 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!