From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vasily Averin Subject: [PATCH v4 11/16] memcg: enable accounting for signals Date: Wed, 28 Apr 2021 09:53:40 +0300 Message-ID: <5567ec19-cd77-01cc-b019-c48f53beb930@virtuozzo.com> References: <8664122a-99d3-7199-869a-781b21b7e712@virtuozzo.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Date:Message-ID:Subject :From; bh=JNK/tV8LgF3p4F8dPZczQO1z3bcUs4vufDHvwz2ZVgs=; b=KKo5bTR5ssb/1fPxbQh 1pVYIS4AJeA+eBipR89M8XEn6J+ExxTv19OELBJOKDUsjG+qzCfcdHBVFfihqYjJ/CgFQxXCKx3hG bvJ6ysmqxVZA4qSYt9pUVARGEoKwhN61z9me0e/gxhcfSvz2A7CjSe8pxjUNNrhm+yrI+t9Rqtk= In-Reply-To: <8664122a-99d3-7199-869a-781b21b7e712-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org> Content-Language: en-US List-ID: Content-Type: text/plain; charset="us-ascii" To: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michal Hocko , Shakeel Butt , Johannes Weiner , Vladimir Davydov Cc: Roman Gushchin , Jens Axboe , "Eric W. Biederman" , Oleg Nesterov , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org When a user send a signal to any another processes it forces the kernel to allocate memory for 'struct sigqueue' objects. The number of signals is limited by RLIMIT_SIGPENDING resource limit, but even the default settings allow each user to consume up to several megabytes of memory. Moreover, an untrusted admin inside container can increase the limit or create new fake users and force them to sent signals. It makes sense to account for these allocations to restrict the host's memory consumption from inside the memcg-limited container. Signed-off-by: Vasily Averin --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/signal.c b/kernel/signal.c index f271835..a7fa849 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -4639,7 +4639,7 @@ void __init signals_init(void) { siginfo_buildtime_checks(); - sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); + sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT); } #ifdef CONFIG_KGDB_KDB -- 1.8.3.1