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arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages

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In order to avoid transient inconsistencies where freed code pages
are remapped writable while stale TLB entries still exist on other
cores, mark the kprobes text pages with the VM_FLUSH_RESET_PERMS
attribute. This instructs the core vmalloc code not to defer the
TLB flush when this region is unmapped and returned to the page
allocator.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ard Biesheuvel 2019-05-23 11:22:55 +01:00 committed by Catalin Marinas
parent 4739d53fcd
commit f83b4f8860
1 changed files with 3 additions and 1 deletions
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4
arch/arm64/kernel/probes/kprobes.c
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@ -122,8 +122,10 @@ void *alloc_insn_page(void)
void *page;
page = vmalloc_exec(PAGE_SIZE);
if (page)
if (page) {
set_memory_ro((unsigned long)page, 1);
set_vm_flush_reset_perms(page);
}
return page;
}