From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f71.google.com (mail-it0-f71.google.com [209.85.214.71]) by kanga.kvack.org (Postfix) with ESMTP id 5B81E6B026B for ; Mon, 27 Nov 2017 23:05:58 -0500 (EST) Received: by mail-it0-f71.google.com with SMTP id n134so19726206itg.3 for ; Mon, 27 Nov 2017 20:05:58 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id a184sor1092729ith.137.2017.11.27.20.05.57 for (Google Transport Security); Mon, 27 Nov 2017 20:05:57 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1511841842-3786-1-git-send-email-zhouzhouyi@gmail.com> References: <1511841842-3786-1-git-send-email-zhouzhouyi@gmail.com> From: Zhouyi Zhou Date: Tue, 28 Nov 2017 12:05:56 +0800 Message-ID: Subject: Re: [PATCH 1/1] kasan: fix livelock in qlist_move_cache Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: aryabinin@virtuozzo.com, Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, "linux-kernel@vger.kernel.org" Cc: Zhouyi Zhou When there are huge amount of quarantined cache allocates in system, number of entries in global_quarantine[i] will be great. Meanwhile, there is no relax in while loop in function qlist_move_cache which hold quarantine_lock. As a result, some userspace programs for example libvirt will complain. On Tue, Nov 28, 2017 at 12:04 PM, wrote: > From: Zhouyi Zhou > > This patch fix livelock by conditionally release cpu to let others > has a chance to run. > > Tested on x86_64. > Signed-off-by: Zhouyi Zhou > --- > mm/kasan/quarantine.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > index 3a8ddf8..33eeff4 100644 > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -265,10 +265,13 @@ static void qlist_move_cache(struct qlist_head *from, > struct kmem_cache *cache) > { > struct qlist_node *curr; > + struct qlist_head tmp_head; > + unsigned long flags; > > if (unlikely(qlist_empty(from))) > return; > > + qlist_init(&tmp_head); > curr = from->head; > qlist_init(from); > while (curr) { > @@ -278,10 +281,17 @@ static void qlist_move_cache(struct qlist_head *from, > if (obj_cache == cache) > qlist_put(to, curr, obj_cache->size); > else > - qlist_put(from, curr, obj_cache->size); > + qlist_put(&tmp_head, curr, obj_cache->size); > > curr = next; > + > + if (need_resched()) { > + spin_unlock_irqrestore(&quarantine_lock, flags); > + cond_resched(); > + spin_lock_irqsave(&quarantine_lock, flags); > + } > } > + qlist_move_all(&tmp_head, from); > } > > static void per_cpu_remove_cache(void *arg) > -- > 2.1.4 > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org