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mm: kfence: fix PG_slab and memcg_data clearing 

It does not reset PG_slab and memcg_data when KFENCE fails to initialize
kfence pool at runtime.  It is reporting a "Bad page state" message when
kfence pool is freed to buddy.  The checking of whether it is a compound
head page seems unnecessary since we already guarantee this when
allocating kfence pool.   Remove the check to simplify the code.

Link: https://lkml.kernel.org/r/20230320030059.20189-1-songmuchun@bytedance.com
Fixes: 0ce20dd840 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Muchun Song 2023-03-20 11:00:59 +08:00 committed by Andrew Morton
parent e900ba10d1
commit 3ee2d7471f
1 changed files with 15 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
mm/kfence/core.c
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@ -561,10 +561,6 @@ static unsigned long kfence_init_pool(void)
if (!i || (i % 2))
continue;
/* Verify we do not have a compound head page. */
if (WARN_ON(compound_head(&pages[i]) != &pages[i]))
return addr;
__folio_set_slab(slab_folio(slab));
#ifdef CONFIG_MEMCG
slab->memcg_data = (unsigned long)&kfence_metadata[i / 2 - 1].objcg |
@ -597,12 +593,26 @@ static unsigned long kfence_init_pool(void)
/* Protect the right redzone. */
if (unlikely(!kfence_protect(addr + PAGE_SIZE)))
return addr;
goto reset_slab;
addr += 2 * PAGE_SIZE;
}
return 0;
reset_slab:
for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) {
struct slab *slab = page_slab(&pages[i]);
if (!i || (i % 2))
continue;
#ifdef CONFIG_MEMCG
slab->memcg_data = 0;
#endif
__folio_clear_slab(slab_folio(slab));
}
return addr;
}
static bool __init kfence_init_pool_early(void)
@ -632,16 +642,6 @@ static bool __init kfence_init_pool_early(void)
* fails for the first page, and therefore expect addr==__kfence_pool in
* most failure cases.
*/
for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) {
struct slab *slab = virt_to_slab(p);
if (!slab)
continue;
#ifdef CONFIG_MEMCG
slab->memcg_data = 0;
#endif
__folio_clear_slab(slab_folio(slab));
}
memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
__kfence_pool = NULL;
return false;