From: Yu Zhao <yuzhao@google.com>
To: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Yu Zhao <yuzhao@google.com>
Subject: [PATCH] mm: avoid slub allocation while holding list_lock
Date: Mon, 9 Sep 2019 00:10:16 -0600 [thread overview]
Message-ID: <20190909061016.173927-1-yuzhao@google.com> (raw)
If we are already under list_lock, don't call kmalloc(). Otherwise we
will run into deadlock because kmalloc() also tries to grab the same
lock.
Instead, allocate pages directly. Given currently page->objects has
15 bits, we only need 1 page. We may waste some memory but we only do
so when slub debug is on.
WARNING: possible recursive locking detected
--------------------------------------------
mount-encrypted/4921 is trying to acquire lock:
(&(&n->list_lock)->rlock){-.-.}, at: ___slab_alloc+0x104/0x437
but task is already holding lock:
(&(&n->list_lock)->rlock){-.-.}, at: __kmem_cache_shutdown+0x81/0x3cb
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&n->list_lock)->rlock);
lock(&(&n->list_lock)->rlock);
*** DEADLOCK ***
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
mm/slub.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 8834563cdb4b..574a53ee31e1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3683,7 +3683,11 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
#ifdef CONFIG_SLUB_DEBUG
void *addr = page_address(page);
void *p;
- unsigned long *map = bitmap_zalloc(page->objects, GFP_ATOMIC);
+ int order;
+ unsigned long *map;
+
+ order = get_order(DIV_ROUND_UP(page->objects, BITS_PER_BYTE));
+ map = (void *)__get_free_pages(GFP_ATOMIC | __GFP_ZERO, order);
if (!map)
return;
slab_err(s, page, text, s->name);
@@ -3698,7 +3702,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
}
}
slab_unlock(page);
- bitmap_free(map);
+ free_pages((unsigned long)map, order);
#endif
}
--
2.23.0.187.g17f5b7556c-goog
next reply other threads:[~2019-09-09 6:10 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 6:10 Yu Zhao [this message]
2019-09-09 16:00 ` [PATCH] mm: avoid slub allocation while holding list_lock Kirill A. Shutemov
[not found] ` <e5e25aa3-651d-92b4-ac82-c5011c66a7cb@I-love.SAKURA.ne.jp>
2019-09-09 21:39 ` Yu Zhao
[not found] ` <201909100141.x8A1fVdu048305@www262.sakura.ne.jp>
2019-09-10 2:16 ` Yu Zhao
2019-09-10 9:16 ` Kirill A. Shutemov
2019-09-11 14:13 ` Andrew Morton
2019-09-12 0:29 ` [PATCH 1/3] mm: correct mask size for slub page->objects Yu Zhao
2019-09-12 0:29 ` [PATCH 2/3] mm: avoid slub allocation while holding list_lock Yu Zhao
2019-09-12 0:44 ` Kirill A. Shutemov
2019-09-12 1:31 ` Yu Zhao
2019-09-12 2:31 ` [PATCH v2 1/4] mm: correct mask size for slub page->objects Yu Zhao
2019-09-12 2:31 ` [PATCH v2 2/4] mm: clean up validate_slab() Yu Zhao
2019-09-12 9:46 ` Kirill A. Shutemov
2019-09-12 2:31 ` [PATCH v2 3/4] mm: avoid slub allocation while holding list_lock Yu Zhao
2019-09-12 10:04 ` Kirill A. Shutemov
2019-09-12 2:31 ` [PATCH v2 4/4] mm: lock slub page when listing objects Yu Zhao
2019-09-12 10:06 ` Kirill A. Shutemov
2019-09-12 21:12 ` Yu Zhao
2019-09-13 14:58 ` Christopher Lameter
2019-09-12 9:40 ` [PATCH v2 1/4] mm: correct mask size for slub page->objects Kirill A. Shutemov
2019-09-12 21:11 ` Yu Zhao
2019-09-12 22:03 ` Kirill A. Shutemov
2019-09-14 0:07 ` [PATCH v3 1/2] mm: clean up validate_slab() Yu Zhao
2019-09-14 0:07 ` [PATCH v3 2/2] mm: avoid slub allocation while holding list_lock Yu Zhao
2019-09-16 8:39 ` [PATCH v3 1/2] mm: clean up validate_slab() Kirill A. Shutemov
2019-11-08 19:39 ` [PATCH v4 " Yu Zhao
2019-11-08 19:39 ` [PATCH v4 2/2] mm: avoid slub allocation while holding list_lock Yu Zhao
2019-11-09 20:52 ` Christopher Lameter
2019-11-09 23:01 ` Yu Zhao
2019-11-09 23:16 ` Christopher Lameter
2019-11-10 18:47 ` Yu Zhao
2019-11-11 15:47 ` Christopher Lameter
2019-11-11 15:55 ` [FIX] slub: Remove kmalloc under list_lock from list_slab_objects() V2 Christopher Lameter
2019-11-30 23:09 ` Andrew Morton
2019-12-02 15:12 ` Christopher Lameter
2019-12-07 22:03 ` Yu Zhao
2020-01-10 14:11 ` Vlastimil Babka
[not found] ` <e0ed44ae-8dae-e8db-9d14-2b09b239af8e@i-love.sakura.ne.jp>
2020-01-13 1:34 ` Christopher Lameter
2019-11-11 18:15 ` [PATCH v4 2/2] mm: avoid slub allocation while holding list_lock Shakeel Butt
2019-09-12 0:29 ` [PATCH 3/3] mm: lock slub page when listing objects Yu Zhao
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