From: Christoph Hellwig <hch@infradead.org>
To: Hailong Liu <hailong.liu@oppo.com>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>,
akpm@linux-foundation.org, Michal Hocko <mhocko@suse.com>,
urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com,
21cnbao@gmail.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, xiang@kernel.org, chao@kernel.org,
Oven <liyangouwen1@oppo.com>
Subject: Re: [RFC PATCH] mm/vmalloc: fix vmalloc which may return null if called with __GFP_NOFAIL
Date: Wed, 8 May 2024 21:51:15 -0700 [thread overview]
Message-ID: <ZjxWQ1Cyx8fhMdKS@infradead.org> (raw)
In-Reply-To: <20240509013059.vegko7dlty7vppy5@oppo.com>
On Thu, May 09, 2024 at 09:30:59AM +0800, Hailong Liu wrote:
> I’m not suggesting that erofs would cause a memleak. What I mean is
> that if kvmalloc is invoked with __GFP_NOFAIL, it must ensure a non-NULL
> return, even in scenarios where memory leaks caused by other processes
> result in the inability to allocate a page. In such a situation, it
> should result in “Kernel panic - not syncing: System is deadlocked
> on memory”.
Yes. __GFP_NOFAIL is a contract that says never ever return NULL.
The callers will generally not handle a NULL return and blindly
dereference it, leading to all kinds of nasty security issues.
Note that deadlocking would be nice, but at least it is just a
denial of service and not a possible privilege escalation.
next prev parent reply other threads:[~2024-05-09 4:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-08 12:58 hailong.liu
2024-05-08 13:41 ` Gao Xiang
2024-05-08 14:13 ` Gao Xiang
2024-05-08 14:43 ` Hailong Liu
2024-05-08 15:10 ` Gao Xiang
2024-05-08 15:31 ` Hailong Liu
2024-05-08 15:40 ` Gao Xiang
2024-05-09 1:30 ` Hailong Liu
2024-05-09 4:51 ` Christoph Hellwig [this message]
2024-05-09 2:20 ` Barry Song
2024-05-09 2:26 ` Barry Song
2024-05-09 2:30 ` Barry Song
2024-05-09 2:39 ` Gao Xiang
2024-05-09 3:09 ` Barry Song
2024-05-09 3:17 ` Gao Xiang
2024-05-09 3:11 ` Gao Xiang
2024-05-09 3:22 ` Hailong Liu
2024-05-09 3:33 ` Hailong Liu
2024-05-09 3:48 ` Barry Song
2024-05-09 4:19 ` Gao Xiang
2024-05-09 4:52 ` Christoph Hellwig
2024-05-09 6:12 ` Barry Song
2024-05-09 7:48 ` Michal Hocko
2024-05-09 8:06 ` Hailong Liu
2024-05-09 8:32 ` Barry Song
2024-05-09 8:57 ` Barry Song
2024-05-09 9:50 ` Hailong Liu
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