The patch titled
Subject: Revert "x86: kmsan: sync metadata pages on page fault"
has been added to the -mm mm-unstable branch. Its filename is
revert-x86-kmsan-sync-metadata-pages-on-page-fault.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-x86-kmsan-sync-metadata-pages-on-page-fault.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Alexander Potapenko <glider@xxxxxxxxxx>
Subject: Revert "x86: kmsan: sync metadata pages on page fault"
Date: Wed, 11 Jan 2023 11:18:06 +0100
This reverts commit 3f1e2c7a9099c1ed32c67f12cdf432ba782cf51f.
As noticed by Qun-Wei Lin, arch_sync_kernel_mappings() in
arch/x86/mm/fault.c is only used with CONFIG_X86_32, whereas KMSAN is only
supported on x86_64, where this code is not compiled.
The patch in question dates back to downstream KMSAN branch based on
v5.8-rc5, it sneaked into upstream unnoticed in v6.1.
Link: https://lkml.kernel.org/r/20230111101806.3236991-1-glider@xxxxxxxxxx
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Reported-by: Qun-Wei Lin <qun-wei.lin@xxxxxxxxxxxx>
Link: https://github.com/google/kmsan/issues/91
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/mm/fault.c | 23 +----------------------
1 file changed, 1 insertion(+), 22 deletions(-)
--- a/arch/x86/mm/fault.c~revert-x86-kmsan-sync-metadata-pages-on-page-fault
+++ a/arch/x86/mm/fault.c
@@ -260,7 +260,7 @@ static noinline int vmalloc_fault(unsign
}
NOKPROBE_SYMBOL(vmalloc_fault);
-static void __arch_sync_kernel_mappings(unsigned long start, unsigned long end)
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
{
unsigned long addr;
@@ -284,27 +284,6 @@ static void __arch_sync_kernel_mappings(
}
}
-void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
-{
- __arch_sync_kernel_mappings(start, end);
-#ifdef CONFIG_KMSAN
- /*
- * KMSAN maintains two additional metadata page mappings for the
- * [VMALLOC_START, VMALLOC_END) range. These mappings start at
- * KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START and
- * have to be synced together with the vmalloc memory mapping.
- */
- if (start >= VMALLOC_START && end < VMALLOC_END) {
- __arch_sync_kernel_mappings(
- start - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START,
- end - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START);
- __arch_sync_kernel_mappings(
- start - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START,
- end - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START);
- }
-#endif
-}
-
static bool low_pfn(unsigned long pfn)
{
return pfn < max_low_pfn;
_
Patches currently in -mm which might be from glider@xxxxxxxxxx are
revert-x86-kmsan-sync-metadata-pages-on-page-fault.patch
