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SubjectRe: [PATCH v2 4/4] mm: kmemleak: kmemleak_*_phys() set address type and check PA when scan
On Fri, Jun 03, 2022 at 11:54:15AM +0800, Patrick Wang wrote:
> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
> index 246a70b7218f..62d1ad8f8a44 100644
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -1156,8 +1156,12 @@ EXPORT_SYMBOL(kmemleak_no_scan);
> void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
> gfp_t gfp)
> {
> - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
> - kmemleak_alloc(__va(phys), size, min_count, gfp);
> + pr_debug("%s(0x%pa, %zu, %d)\n", __func__, &phys, size, min_count);
> +
> + if (kmemleak_enabled && !min_count)
> + /* create object with OBJECT_PHYS flag */
> + create_object((unsigned long)phys, size, min_count,
> + gfp, true);
> }

With an early patch, just drop min_count altogether from this API,
assume 0.

> EXPORT_SYMBOL(kmemleak_alloc_phys);
>
> @@ -1170,8 +1174,10 @@ EXPORT_SYMBOL(kmemleak_alloc_phys);
> */
> void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
> {
> - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
> - kmemleak_free_part(__va(phys), size);
> + pr_debug("%s(0x%pa)\n", __func__, &phys);
> +
> + if (kmemleak_enabled)
> + delete_object_part((unsigned long)phys, size, true);
> }
> EXPORT_SYMBOL(kmemleak_free_part_phys);
>
> @@ -1182,8 +1188,10 @@ EXPORT_SYMBOL(kmemleak_free_part_phys);
> */
> void __ref kmemleak_not_leak_phys(phys_addr_t phys)
> {
> - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
> - kmemleak_not_leak(__va(phys));
> + pr_debug("%s(0x%pa)\n", __func__, &phys);
> +
> + if (kmemleak_enabled)
> + make_gray_object((unsigned long)phys, true);
> }
> EXPORT_SYMBOL(kmemleak_not_leak_phys);

This function doesn't have any callers, so please remove it.

> @@ -1194,8 +1202,10 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys);
> */
> void __ref kmemleak_ignore_phys(phys_addr_t phys)
> {
> - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
> - kmemleak_ignore(__va(phys));
> + pr_debug("%s(0x%pa)\n", __func__, &phys);
> +
> + if (kmemleak_enabled)
> + make_black_object((unsigned long)phys, true);
> }
> EXPORT_SYMBOL(kmemleak_ignore_phys);

Ah, that's still in use and we do need make_black_object(), contrary to
what I commented on a previous patch. We can still avoid changing
make_gray_object().

(we could replace the kmemleak_ignore_phys() calls
kmemleak_free_part_phys() but that's not in line with what we do for the
virtual objects)

> @@ -1468,6 +1478,17 @@ static void kmemleak_scan(void)
> dump_object_info(object);
> }
> #endif
> +
> + /* ignore objects outside lowmem (paint them black) */
> + if ((object->flags & OBJECT_PHYS) &&
> + !(object->flags & OBJECT_NO_SCAN)) {
> + unsigned long phys = object->pointer;
> +
> + if (PHYS_PFN(phys) < min_low_pfn ||
> + PHYS_PFN(phys + object->size) >= max_low_pfn)
> + __paint_it(object, KMEMLEAK_BLACK);
> + }
> +
> /* reset the reference count (whiten the object) */
> object->count = 0;
> if (color_gray(object) && get_object(object))

This looks fine.

--
Catalin

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