Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fix from Catalin Marinas:
"Fix PTRACE_PEEKMTETAGS access to an mmapped region before the first
write"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mte: Allow PTRACE_PEEKMTETAGS access to the zero page
+3
-6
+1
-5
arch/arm64/kernel/cpufeature.c
+1
-5
arch/arm64/kernel/cpufeature.c
···
1701
1701
#ifdef CONFIG_ARM64_MTE
1702
1702
static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap)
1703
1703
{
1704
-
static bool cleared_zero_page = false;
1705
-
1706
1704
/*
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1705
* Clear the tags in the zero page. This needs to be done via the
1708
1706
* linear map which has the Tagged attribute.
1709
1707
*/
1710
-
if (!cleared_zero_page) {
1711
-
cleared_zero_page = true;
1708
+
if (!test_and_set_bit(PG_mte_tagged, &ZERO_PAGE(0)->flags))
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1709
mte_clear_page_tags(lm_alias(empty_zero_page));
1713
-
}
1714
1710
1715
1711
kasan_init_hw_tags_cpu();
1716
1712
}
+2
-1
arch/arm64/kernel/mte.c
+2
-1
arch/arm64/kernel/mte.c
···
329
329
* would cause the existing tags to be cleared if the page
330
330
* was never mapped with PROT_MTE.
331
331
*/
332
-
if (!test_bit(PG_mte_tagged, &page->flags)) {
332
+
if (!(vma->vm_flags & VM_MTE)) {
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ret = -EOPNOTSUPP;
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put_page(page);
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break;
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}
337
+
WARN_ON_ONCE(!test_bit(PG_mte_tagged, &page->flags));
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/* limit access to the end of the page */
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offset = offset_in_page(addr);