On Tue, 15 Oct 2024 at 23:37, Linus Walleij linus.walleij@linaro.org wrote:
When sync:ing the VMALLOC area to other CPUs, make sure to also sync the KASAN shadow memory for the VMALLOC area, so that we don't get stale entries for the shadow memory in the top level PGD.
Cc: stable@vger.kernel.org Fixes: 565cbaad83d8 ("ARM: 9202/1: kasan: support CONFIG_KASAN_VMALLOC") Link: https://lore.kernel.org/linux-arm-kernel/a1a1d062-f3a2-4d05-9836-3b098de9db6... Reported-by: Clement LE GOFFIC clement.legoffic@foss.st.com Suggested-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Linus Walleij linus.walleij@linaro.org
arch/arm/mm/ioremap.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index 794cfea9f9d4..449f1f04814c 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -23,6 +23,7 @@ */ #include <linux/module.h> #include <linux/errno.h> +#include <linux/kasan.h> #include <linux/mm.h> #include <linux/vmalloc.h> #include <linux/io.h> @@ -125,6 +126,12 @@ void __check_vmalloc_seq(struct mm_struct *mm) pgd_offset_k(VMALLOC_START), sizeof(pgd_t) * (pgd_index(VMALLOC_END) - pgd_index(VMALLOC_START)));
if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {memcpy(pgd_offset(mm, (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START)),pgd_offset_k((unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START)),sizeof(pgd_t) * (pgd_index((unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END)) -pgd_index((unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START))));}
+1 to Russell's suggestion to change this wall of text into something legible.
Then, there is another part to this: in arch/arm/kernel/traps.c, we have the following code
void arch_sync_kernel_mappings(unsigned long start, unsigned long end) { if (start < VMALLOC_END && end > VMALLOC_START) atomic_inc_return_release(&init_mm.context.vmalloc_seq); }
where we only bump vmalloc_seq if the updated region overlaps with the vmalloc region, so this will need a similar treatment afaict.