Re: [PATCH] mm: memcontrol: fix possible css ref leak on oom
From: Vladimir Davydov <hidden>
Date: 2016-05-24 09:17:14
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On Tue, May 24, 2016 at 10:47:37AM +0200, Michal Hocko wrote:
On Tue 24-05-16 11:43:19, Vladimir Davydov wrote:quoted
On Mon, May 23, 2016 at 07:44:43PM +0200, Michal Hocko wrote:quoted
On Mon 23-05-16 19:02:10, Vladimir Davydov wrote:quoted
mem_cgroup_oom may be invoked multiple times while a process is handling a page fault, in which case current->memcg_in_oom will be overwritten leaking the previously taken css reference.Have you seen this happening? I was under impression that the page fault paths that have oom enabled will not retry allocations.filemap_fault will, for readahead.I thought that the readahead is __GFP_NORETRY so we do not trigger OOM killer.
Hmm, interesting. We do allocate readahead pages with __GFP_NORETRY, but we add them to page cache and hence charge with GFP_KERNEL or GFP_NOFS mask, see __do_page_cache_readahaed -> read_pages. -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>