4.9-stable patches

added patches:
	kvm-arm-arm64-don-t-reschedule-in-unmap_stage2_range.patch

diff --git a/queue-4.9/kvm-arm-arm64-don-t-reschedule-in-unmap_stage2_range.patch b/queue-4.9/kvm-arm-arm64-don-t-reschedule-in-unmap_stage2_range.patch
new file mode 100644 (file)
index 0000000..794f4a9
--- /dev/null
+++ b/queue-4.9/kvm-arm-arm64-don-t-reschedule-in-unmap_stage2_range.patch
@@ -0,0 +1,48 @@
+From will@kernel.org  Mon Aug 24 18:14:19 2020
+From: Will Deacon <will@kernel.org>
+Date: Mon, 24 Aug 2020 12:29:40 +0100
+Subject: KVM: arm/arm64: Don't reschedule in unmap_stage2_range()
+To: gregkh@linuxfoundation.org
+Cc: linux-kernel@vger.kernel.org, maz@kernel.org, suzuki.poulose@arm.com, james.morse@arm.com, pbonzini@redhat.com, kernel-team@android.com, Will Deacon <will@kernel.org>, stable@vger.kernel.org
+Message-ID: <20200824112940.24706-1-will@kernel.org>
+
+From: Will Deacon <will@kernel.org>
+
+Upstream commits fdfe7cbd5880 ("KVM: Pass MMU notifier range flags to
+kvm_unmap_hva_range()") and b5331379bc62 ("KVM: arm64: Only reschedule
+if MMU_NOTIFIER_RANGE_BLOCKABLE is not set") fix a "sleeping from invalid
+context" BUG caused by unmap_stage2_range() attempting to reschedule when
+called on the OOM path.
+
+Unfortunately, these patches rely on the MMU notifier callback being
+passed knowledge about whether or not blocking is permitted, which was
+introduced in 4.19. Rather than backport this considerable amount of
+infrastructure just for KVM on arm, instead just remove the conditional
+reschedule.
+
+Cc: <stable@vger.kernel.org> # v4.9 only
+Cc: Marc Zyngier <maz@kernel.org>
+Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
+Cc: James Morse <james.morse@arm.com>
+Signed-off-by: Will Deacon <will@kernel.org>
+Acked-by: Marc Zyngier <maz@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/arm/kvm/mmu.c |    6 ------
+ 1 file changed, 6 deletions(-)
+
+--- a/arch/arm/kvm/mmu.c
++++ b/arch/arm/kvm/mmu.c
+@@ -298,12 +298,6 @@ static void unmap_stage2_range(struct kv
+               next = stage2_pgd_addr_end(addr, end);
+               if (!stage2_pgd_none(*pgd))
+                       unmap_stage2_puds(kvm, pgd, addr, next);
+-              /*
+-               * If the range is too large, release the kvm->mmu_lock
+-               * to prevent starvation and lockup detector warnings.
+-               */
+-              if (next != end)
+-                      cond_resched_lock(&kvm->mmu_lock);
+       } while (pgd++, addr = next, addr != end);
+ }
+ 

diff --git a/queue-4.9/series b/queue-4.9/series
index cc9d5b10e6e6f0694041a51c5ac60f196ab59d00..d5a650d33e71b28462614335d80097735f990ac6 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -36,3 +36,4 @@ epoll-keep-a-reference-on-files-added-to-the-check-list.patch
 do_epoll_ctl-clean-the-failure-exits-up-a-bit.patch
 mm-hugetlb-fix-calculation-of-adjust_range_if_pmd_sharing_possible.patch
 xen-don-t-reschedule-in-preemption-off-sections.patch
+kvm-arm-arm64-don-t-reschedule-in-unmap_stage2_range.patch