Thread (14 messages) 14 messages, 4 authors, 2020-12-10
STALE1994d LANDED

[PATCH 1/8] powerpc/64s/powernv: Fix memory corruption when saving SLB entries on MCE

From: Nicholas Piggin <npiggin@gmail.com>
Date: 2020-11-28 07:10:59
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Michael Ellerman, Linus Torvalds

This can be hit by an HPT guest running on an HPT host and bring down
the host, so it's quite important to fix.

Fixes: 7290f3b3d3e66 ("powerpc/64s/powernv: machine check dump SLB contents")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/platforms/powernv/setup.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 46115231a3b2..4426a109ec2f 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -211,11 +211,16 @@ static void __init pnv_init(void)
 		add_preferred_console("hvc", 0, NULL);
 
 	if (!radix_enabled()) {
+		size_t size = sizeof(struct slb_entry) * mmu_slb_size;
 		int i;
 
 		/* Allocate per cpu area to save old slb contents during MCE */
-		for_each_possible_cpu(i)
-			paca_ptrs[i]->mce_faulty_slbs = memblock_alloc_node(mmu_slb_size, __alignof__(*paca_ptrs[i]->mce_faulty_slbs), cpu_to_node(i));
+		for_each_possible_cpu(i) {
+			paca_ptrs[i]->mce_faulty_slbs =
+					memblock_alloc_node(size,
+						__alignof__(struct slb_entry),
+						cpu_to_node(i));
+		}
 	}
 }
 
-- 
2.23.0
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