From: Linus Torvalds <torvalds@linux-foundation.org>
To: Barry Song <21cnbao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>,
akpm@linux-foundation.org, linux-mm@kvack.org,
42.hyeyoo@gmail.com, cl@linux.com, hailong.liu@oppo.com,
hch@infradead.org, iamjoonsoo.kim@lge.com, mhocko@suse.com,
penberg@kernel.org, rientjes@google.com,
roman.gushchin@linux.dev, urezki@gmail.com,
v-songbaohua@oppo.com, vbabka@suse.cz,
virtualization@lists.linux.dev
Subject: Re: [PATCH v3 0/4] mm: clarify nofail memory allocation
Date: Mon, 19 Aug 2024 12:33:17 -0700 [thread overview]
Message-ID: <CAHk-=who4GDu0gXZ2xWdpmTOQ_OZaWfgVmcADUGo05Eoa-jKxA@mail.gmail.com> (raw)
In-Reply-To: <CAGsJ_4xwj+trzpOS4b-RSHtqHkD4+0g1Sadr7YCiauOBgd35dQ@mail.gmail.com>
On Mon, 19 Aug 2024 at 12:23, Barry Song <21cnbao@gmail.com> wrote:
>
>
> That could be an exploit taking advantage of those improper callers,
So?
FIX THE BUGGY CODE.
Don't make insane and incorrect changes to the MM code and spread
Fear, Uncertainty and Doubt.
> thus it wouldn’t necessarily result in an immediate oops in callers but
> result in an exploit
No. Any bug can be an exploit. Don't try to make this something
special by calling it an exploit.
NULL pointer dereferences are some of the *least* worrisome bugs,
because we don't allow people to mmap the NULL area anyway.
So just stop spreading FUD. We don't improve the kernel by making
excuses for bugs, we improve it by fixing things.
And any caller that asks for NOFAIL with bad parameters is buggy. The
MM code should NOT try to fix it up, and dammit, BUG_ON() is not
acceptable as a debugging help. Never was, never will be.
Worry-warts already do "reboot-on-warn".
Linus
next prev parent reply other threads:[~2024-08-19 19:33 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-17 6:24 [PATCH v3 0/4] mm: clarify nofail memory allocation Barry Song
2024-08-17 6:24 ` [PATCH v3 1/4] vduse: avoid using __GFP_NOFAIL Barry Song
2024-08-17 6:24 ` [PATCH v3 2/4] mm: document __GFP_NOFAIL must be blockable Barry Song
2024-08-17 6:24 ` [PATCH v3 3/4] mm: BUG_ON to avoid NULL deference while __GFP_NOFAIL fails Barry Song
2024-08-19 9:43 ` David Hildenbrand
2024-08-19 9:47 ` Barry Song
2024-08-19 9:55 ` David Hildenbrand
2024-08-19 10:02 ` Barry Song
2024-08-19 12:33 ` David Hildenbrand
2024-08-19 12:48 ` Barry Song
2024-08-19 12:49 ` David Hildenbrand
2024-08-19 17:12 ` Michal Hocko
2024-08-19 17:17 ` Linus Torvalds
2024-08-19 20:24 ` David Hildenbrand
2024-08-19 20:35 ` Linus Torvalds
2024-08-19 21:57 ` David Hildenbrand
2024-08-19 22:13 ` Linus Torvalds
2024-08-20 6:17 ` Michal Hocko
2024-08-19 12:49 ` Christoph Hellwig
2024-08-19 12:51 ` David Hildenbrand
2024-08-19 12:53 ` Christoph Hellwig
2024-08-19 13:14 ` David Hildenbrand
2024-08-19 13:05 ` Barry Song
2024-08-19 13:10 ` David Hildenbrand
2024-08-19 13:19 ` Barry Song
2024-08-19 13:22 ` David Hildenbrand
2024-08-17 6:24 ` [PATCH v3 4/4] mm: prohibit NULL deference exposed for unsupported non-blockable __GFP_NOFAIL Barry Song
2024-08-18 2:55 ` Yafang Shao
2024-08-18 3:48 ` Barry Song
2024-08-18 5:51 ` Yafang Shao
2024-08-18 6:27 ` Barry Song
2024-08-18 6:45 ` Barry Song
2024-08-18 7:07 ` Yafang Shao
2024-08-18 7:25 ` Barry Song
2024-08-19 7:51 ` Michal Hocko
2024-08-19 7:50 ` Michal Hocko
2024-08-19 9:25 ` Yafang Shao
2024-08-19 9:39 ` Barry Song
2024-08-19 9:45 ` Yafang Shao
2024-08-19 10:10 ` Barry Song
2024-08-19 11:56 ` Yafang Shao
2024-08-19 12:09 ` Michal Hocko
2024-08-19 12:17 ` Yafang Shao
2024-08-19 14:01 ` Michal Hocko
2024-08-19 10:17 ` Michal Hocko
2024-08-19 11:56 ` Yafang Shao
2024-08-19 12:04 ` Michal Hocko
2024-08-19 9:44 ` David Hildenbrand
2024-08-19 10:19 ` Michal Hocko
2024-08-19 12:48 ` David Hildenbrand
2024-08-19 13:02 ` [PATCH v3 0/4] mm: clarify nofail memory allocation David Hildenbrand
2024-08-19 16:05 ` Linus Torvalds
2024-08-19 19:23 ` Barry Song
2024-08-19 19:33 ` Linus Torvalds [this message]
2024-08-19 21:48 ` Barry Song
2024-08-20 6:24 ` Michal Hocko
2024-08-21 12:40 ` Yafang Shao
2024-08-21 22:59 ` Linus Torvalds
2024-08-22 6:21 ` Michal Hocko
2024-08-22 6:40 ` Linus Torvalds
2024-08-22 6:56 ` Linus Torvalds
2024-08-22 7:47 ` Michal Hocko
2024-08-22 7:57 ` Barry Song
2024-08-22 8:24 ` Michal Hocko
2024-08-22 8:39 ` David Hildenbrand
2024-08-22 9:08 ` Linus Torvalds
2024-08-22 9:16 ` Michal Hocko
2024-08-22 9:24 ` Linus Torvalds
2024-08-22 9:11 ` Michal Hocko
2024-08-22 9:18 ` Linus Torvalds
2024-08-22 9:33 ` Michal Hocko
2024-08-22 9:44 ` Linus Torvalds
2024-08-22 9:59 ` Michal Hocko
2024-08-22 10:30 ` Linus Torvalds
2024-08-22 10:46 ` Michal Hocko
2024-08-22 9:27 ` David Hildenbrand
2024-08-22 9:34 ` Linus Torvalds
2024-08-22 9:43 ` David Hildenbrand
2024-08-22 9:53 ` Linus Torvalds
2024-08-22 11:58 ` Johannes Weiner
2024-08-26 12:10 ` Vlastimil Babka
2024-08-27 6:57 ` Linus Torvalds
2024-08-27 7:15 ` Barry Song
2024-08-27 7:38 ` Vlastimil Babka
2024-08-27 7:50 ` Barry Song
2024-08-29 10:24 ` Vlastimil Babka
2024-08-29 11:53 ` Barry Song
2024-08-29 13:20 ` Michal Hocko
2024-08-29 21:27 ` Barry Song
2024-08-29 22:31 ` Barry Song
2024-08-30 7:24 ` Michal Hocko
2024-08-30 7:37 ` Vlastimil Babka
2024-08-22 9:41 ` Michal Hocko
2024-08-22 9:42 ` David Hildenbrand
2024-08-22 7:01 ` Gao Xiang
2024-08-22 7:54 ` Michal Hocko
2024-08-22 8:04 ` Gao Xiang
2024-08-22 14:35 ` Yafang Shao
2024-08-22 15:02 ` Gao Xiang
2024-08-22 6:37 ` Barry Song
2024-08-22 14:22 ` Yafang Shao
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