On Sun, Aug 23, 2020 at 02:27:05PM +0200, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 5.8-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b5331379bc62611d1026173a09c73573384201d9 Mon Sep 17 00:00:00 2001 From: Will Deacon will@kernel.org Date: Tue, 11 Aug 2020 11:27:25 +0100 Subject: [PATCH] KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set
When an MMU notifier call results in unmapping a range that spans multiple PGDs, we end up calling into cond_resched_lock() when crossing a PGD boundary, since this avoids running into RCU stalls during VM teardown. Unfortunately, if the VM is destroyed as a result of OOM, then blocking is not permitted and the call to the scheduler triggers the following BUG():
This is in the same boat as:
https://lore.kernel.org/r/20200824112156.GA24319@willie-the-truck
so please drop it from the stable queues while I cook some backports for you.
Thanks,
Will