TITLE: WARNING: bad unlock balance in restore_fpsimd_context
TYPE: LOCKDEP

[  753.902734][ T4405] =====================================
[  753.903682][ T4405] WARNING: bad unlock balance detected!
[  753.904679][ T4405] 5.9.0-12994-gf9893351acae #15 Not tainted
[  753.905336][ T4405] -------------------------------------
[  753.905757][ T4405] syz-fuzzer/4405 is trying to release lock (&mm->mmap_lock) at:
[  753.906721][ T4405] [<ffffa00010726344>] __might_fault+0x154/0x1b0
[  753.907110][ T4405] but there are no more locks to release!
[  753.907490][ T4405] 
[  753.907490][ T4405] other info that might help us debug this:
[  753.908261][ T4405] no locks held by syz-fuzzer/4405.
[  753.908865][ T4405] 
[  753.908865][ T4405] stack backtrace:
[  753.910040][ T4405] CPU: 1 PID: 4405 Comm: syz-fuzzer Not tainted 5.9.0-12994-gf9893351acae #15
[  753.910746][ T4405] Hardware name: linux,dummy-virt (DT)
[  753.911978][ T4405] Call trace:
[  753.912644][ T4405]  dump_backtrace+0x0/0x4d0
[  753.913320][ T4405]  show_stack+0x2c/0x80
[  753.914002][ T4405]  dump_stack+0x1b0/0x254
[  753.914652][ T4405]  print_unlock_imbalance_bug+0x170/0x188
[  753.915352][ T4405]  lock_release+0x69c/0xa68
[  753.916058][ T4405]  __might_fault+0x170/0x1b0
[  753.916798][ T4405]  restore_fpsimd_context+0x418/0x798
[  753.917532][ T4405]  __arm64_sys_rt_sigreturn+0x15d0/0x1990
[  753.918229][ T4405]  el0_svc_common.constprop.0+0x158/0x530
[  753.918921][ T4405]  do_el0_svc+0x58/0x148
[  753.919594][ T4405]  el0_sync_handler+0x1f4/0x200
[  753.920423][ T4405]  el0_sync+0x174/0x180
