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authorChristopher Lameter <cl@linux.com>2020-06-02 07:45:53 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-02 20:59:06 +0300
commitaa456c7aebb14a4ff47611586397b5b3e84fbf37 (patch)
tree6b39f7c734fc0375495bb493c711a078a91dc631 /mm/slub.c
parentd7660ce5914d396242bfc56c8f45ef117101fb58 (diff)
downloadlinux-aa456c7aebb14a4ff47611586397b5b3e84fbf37.tar.xz
slub: remove kmalloc under list_lock from list_slab_objects() V2
list_slab_objects() is called when a slab is destroyed and there are objects still left to list the objects in the syslog. This is a pretty rare event. And there it seems we take the list_lock and call kmalloc while holding that lock. Perform the allocation in free_partial() before the list_lock is taken. Fixes: bbd7d57bfe852d9788bae5fb171c7edb4021d8ac ("slub: Potential stack overflow") Signed-off-by: Christopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Yu Zhao <yuzhao@google.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2002031721250.1668@www.lameter.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 2ae5580433af..3a76de69a268 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3766,12 +3766,14 @@ error:
}
static void list_slab_objects(struct kmem_cache *s, struct page *page,
- const char *text)
+ const char *text, unsigned long *map)
{
#ifdef CONFIG_SLUB_DEBUG
void *addr = page_address(page);
void *p;
- unsigned long *map;
+
+ if (!map)
+ return;
slab_err(s, page, text, s->name);
slab_lock(page);
@@ -3784,8 +3786,6 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
print_tracking(s, p);
}
}
- put_map(map);
-
slab_unlock(page);
#endif
}
@@ -3799,6 +3799,11 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
{
LIST_HEAD(discard);
struct page *page, *h;
+ unsigned long *map = NULL;
+
+#ifdef CONFIG_SLUB_DEBUG
+ map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
+#endif
BUG_ON(irqs_disabled());
spin_lock_irq(&n->list_lock);
@@ -3808,11 +3813,16 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
list_add(&page->slab_list, &discard);
} else {
list_slab_objects(s, page,
- "Objects remaining in %s on __kmem_cache_shutdown()");
+ "Objects remaining in %s on __kmem_cache_shutdown()",
+ map);
}
}
spin_unlock_irq(&n->list_lock);
+#ifdef CONFIG_SLUB_DEBUG
+ bitmap_free(map);
+#endif
+
list_for_each_entry_safe(page, h, &discard, slab_list)
discard_slab(s, page);
}