+ xor-add-missing-vzeroupper-to-avx-code.patch added to mm-nonmm-unstable branch

+ xor-add-missing-vzeroupper-to-avx-code.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: xor: add missing vzeroupper to AVX code
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     xor-add-missing-vzeroupper-to-avx-code.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/xor-add-missing-vzeroupper-to-avx-code.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Eric Biggers <ebiggers@kernel.org>
Subject: xor: add missing vzeroupper to AVX code
Date: Mon, 31 Aug 2026 14:22:48 -0700

Since the AVX optimized XOR code uses YMM registers, execute vzeroupper
before returning from it.  This is needed to avoid degrading the
performance of any later SSE code that may happen to be executed.

Link: https://lore.kernel.org/20260831212248.213805-1-ebiggers@kernel.org
Fixes: ea4d26ae24e5 ("raid5: add AVX optimized RAID5 checksumming")
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/raid/xor/x86/xor-avx.c |    1 +
 1 file changed, 1 insertion(+)

--- a/lib/raid/xor/x86/xor-avx.c~xor-add-missing-vzeroupper-to-avx-code
+++ a/lib/raid/xor/x86/xor-avx.c
@@ -147,6 +147,7 @@ static void xor_gen_avx(void *dest, void
 {
 	kernel_fpu_begin();
 	xor_gen_avx_inner(dest, srcs, src_cnt, bytes);
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
_

Patches currently in -mm which might be from ebiggers@kernel.org are

xor-add-missing-vzeroupper-to-avx-code.patch
raid6-add-missing-vzeroupper-to-avx2-code.patch
raid6-add-missing-vzeroupper-to-avx-512-code.patch