On 2022/6/1 00:29, Catalin Marinas wrote:
On Tue, May 31, 2022 at 11:08:23PM +0800, Patrick Wang wrote:
@@ -1132,8 +1135,13 @@ 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%p, %zu, %d)\n", __func__, __va(phys), size, min_count);
I'd print just phys here since that's the function argument.
Will do.
+ if (kmemleak_enabled && (unsigned long)__va(phys) >= PAGE_OFFSET &&
+ !IS_ERR(__va(phys)))
+ /* create object with OBJECT_PHYS flag */
+ create_object((unsigned long)__va(phys), size, min_count,
+ gfp, true);
Do we still need to check for __va(phys) >= PAGE_OFFSET? Also I don't
think IS_ERR(__va(phys)) makes sense, we can't store an error in a
physical address. The kmemleak_alloc_phys() function is only called on
successful allocation, so shouldn't bother with error codes.
In this commit:
972fa3a7c17c(mm: kmemleak: alloc gray object for reserved
region with direct map)
The kmemleak_alloc_phys() function is called directly by passing
physical address from devicetree. So I'm concerned that could
__va() => __pa() convert always get the phys back? I thought
check for __va(phys) might help, but it probably dosen't work
and using IS_ERR is indeed inappropriate.
We might have to store phys in object and convert it via __va()
for normal use like:
#define object_pointer(obj) \
(obj->flags & OBJECT_PHYS ? (unsigned long)__va((void *)obj->pointer) \
: obj->pointer)
@@ -1436,6 +1441,13 @@ static void kmemleak_scan(void)
dump_object_info(object);
}
#endif
+
+ /* outside lowmem, make it black */
Maybe a bit more verbose:
/* ignore objects outside lowmem (paint them black) */
Will do.
+ if (object->flags & OBJECT_PHYS)
+ if (PHYS_PFN(__pa((void *)object->pointer)) < min_low_pfn ||
+ PHYS_PFN(__pa((void *)object->pointer)) >= max_low_pfn)
+ __paint_it(object, KMEMLEAK_BLACK);
I'd skip the checks if the object is OBJECT_NO_SCAN (side-effect of
__paint_it()) so that the next scan won't have to go through the __pa()
checks again. It's also probably more correct to check the upper object
boundary). Something like:
if ((object->flags & OBJECT_PHYS) &&
!(object->flags & OBJECT_NO_SCAN)) {
unsigned long phys = __pa((void *)object->pointer);
if (PHYS_PFN(phys) < min_low_pfn ||
PHYS_PFN(phys + object->size) >= max_low_pfn)
__paint_it(object, KMEMLEAK_BLACK);
}
Right, much more thorough. Will do.
Thanks,
Patrick
