TITLE: WARNING: locking bug in kernel_wait4
TYPE: LOCKDEP

[  483.562491][ T4115] =============================
[  483.563138][ T4115] [ BUG: Invalid wait context ]
[  483.563925][ T4115] 5.9.0-12994-gf9893351acae #15 Not tainted
[  483.564520][ T4115] -----------------------------
[  483.565141][ T4115] dhcpcd/4115 is trying to lock:
[  483.566013][ T4115] ffff000041e68118 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x108/0x1b0
[  483.568509][ T4115] other info that might help us debug this:
[  483.569246][ T4115] context-{4:4}
[  483.569886][ T4115] 1 lock held by dhcpcd/4115:
[  483.570483][ T4115]  #0: ffffa00019769560 (rcu_read_lock){....}-{1:2}, at: count_memcg_event_mm+0x24/0x2f0
[  483.572502][ T4115] stack backtrace:
[  483.573642][ T4115] CPU: 0 PID: 4115 Comm: dhcpcd Not tainted 5.9.0-12994-gf9893351acae #15
[  483.574478][ T4115] Hardware name: linux,dummy-virt (DT)
[  483.575747][ T4115] Call trace:
[  483.576425][ T4115]  dump_backtrace+0x0/0x4d0
[  483.577101][ T4115]  show_stack+0x2c/0x80
[  483.577800][ T4115]  dump_stack+0x1b0/0x254
[  483.578478][ T4115]  __lock_acquire+0x1a04/0x4930
[  483.579234][ T4115]  lock_acquire+0x278/0xb88
[  483.579965][ T4115]  __might_fault+0x138/0x1b0
[  483.580648][ T4115]  kernel_wait4+0x174/0x368
[  483.581356][ T4115]  __do_sys_wait4+0x210/0x2b8
[  483.582036][ T4115]  __arm64_sys_wait4+0x8c/0xd0
[  483.582872][ T4115]  el0_svc_common.constprop.0+0x158/0x530
[  483.583669][ T4115]  do_el0_svc+0x58/0x148
[  483.584310][ T4115]  el0_sync_handler+0x1f4/0x200
[  483.584953][ T4115]  el0_sync+0x174/0x180
