+ raid6-add-missing-vzeroupper-to-avx2-code.patch added to mm-nonmm-unstable branch

+ raid6-add-missing-vzeroupper-to-avx2-code.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: raid6: add missing vzeroupper to AVX2 code
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     raid6-add-missing-vzeroupper-to-avx2-code.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/raid6-add-missing-vzeroupper-to-avx2-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: raid6: add missing vzeroupper to AVX2 code
Date: Mon, 31 Aug 2026 14:23:08 -0700

Since the AVX2 optimized RAID6 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/20260831212308.213855-1-ebiggers@kernel.org
Fixes: 2c935842bdb4 ("lib/raid6: Add AVX2 optimized gen_syndrome functions")
Fixes: 7056741fd9fc ("lib/raid6: Add AVX2 optimized recovery functions")
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/raid6/x86/avx2.c       |    6 ++++++
 lib/raid/raid6/x86/recov_avx2.c |    2 ++
 2 files changed, 8 insertions(+)

--- a/lib/raid/raid6/x86/avx2.c~raid6-add-missing-vzeroupper-to-avx2-code
+++ a/lib/raid/raid6/x86/avx2.c
@@ -67,6 +67,7 @@ static void raid6_avx21_gen_syndrome(int
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -115,6 +116,7 @@ static void raid6_avx21_xor_syndrome(int
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -175,6 +177,7 @@ static void raid6_avx22_gen_syndrome(int
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -243,6 +246,7 @@ static void raid6_avx22_xor_syndrome(int
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -334,6 +338,7 @@ static void raid6_avx24_gen_syndrome(int
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -444,6 +449,7 @@ static void raid6_avx24_xor_syndrome(int
 		asm volatile("vmovntdq %%ymm14,%0" : "=m" (q[d+96]));
 	}
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
--- a/lib/raid/raid6/x86/recov_avx2.c~raid6-add-missing-vzeroupper-to-avx2-code
+++ a/lib/raid/raid6/x86/recov_avx2.c
@@ -176,6 +176,7 @@ static void raid6_2data_recov_avx2(int d
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -293,6 +294,7 @@ static void raid6_datap_recov_avx2(int d
 #endif
 	}
 
+	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