From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: "Kirill A. Shutemov" <kirill@shutemov.name>, Yu Zhao <yuzhao@google.com>
Cc: 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>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: avoid slub allocation while holding list_lock
Date: Tue, 10 Sep 2019 05:57:22 +0900 [thread overview]
Message-ID: <e5e25aa3-651d-92b4-ac82-c5011c66a7cb@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20190909160052.cxpfdmnrqucsilz2@box>
On 2019/09/10 1:00, Kirill A. Shutemov wrote:
> On Mon, Sep 09, 2019 at 12:10:16AM -0600, Yu Zhao wrote:
>> 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>
>
> Looks sane to me:
>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>
Really?
Since page->objects is handled as bitmap, alignment should be BITS_PER_LONG
than BITS_PER_BYTE (though in this particular case, get_order() would
implicitly align BITS_PER_BYTE * PAGE_SIZE). But get_order(0) is an
undefined behavior.
next prev parent reply other threads:[~2019-09-09 20:57 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 6:10 [PATCH] mm: avoid slub allocation while holding list_lock Yu Zhao
2019-09-09 16:00 ` Kirill A. Shutemov
2019-09-09 20:57 ` Tetsuo Handa [this message]
2019-09-09 21:39 ` Yu Zhao
2019-09-10 1:41 ` Tetsuo Handa
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
2019-12-01 1:17 ` Tetsuo Handa
2019-12-02 15:12 ` Christopher Lameter
2019-12-07 22:03 ` Yu Zhao
2020-01-10 14:11 ` Vlastimil Babka
2020-01-12 11:03 ` Tetsuo Handa
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e5e25aa3-651d-92b4-ac82-c5011c66a7cb@I-love.SAKURA.ne.jp \
--to=penguin-kernel@i-love.sakura.ne.jp \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=yuzhao@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).