From: Vlastimil Babka <vbabka@suse.cz>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, stable <stable@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
Daniel Micay <danielmicay@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nathan Chancellor <nathan@kernel.org>,
linux-mm@kvack.org, llvm@lists.linux.dev
Subject: Re: [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller
Date: Fri, 18 Feb 2022 19:54:14 +0100 [thread overview]
Message-ID: <c237f6d1-4219-0e6d-6aca-9c29d060bb4f@suse.cz> (raw)
In-Reply-To: <Yg/eG4X7Esa0h1al@kroah.com>
On 2/18/22 18:57, Greg Kroah-Hartman wrote:
> On Fri, Feb 18, 2022 at 06:14:55PM +0100, Vlastimil Babka wrote:
>> On 2/18/22 14:13, Greg Kroah-Hartman wrote:
>> > Commit c37495d6254c ("slab: add __alloc_size attributes for better
>> > bounds checking") added __alloc_size attributes to a bunch of kmalloc
>> > function prototypes. Unfortunately the change to __kmalloc_track_caller
>> > seems to cause clang to generate broken code and the first time this is
>> > called when booting, the box will crash.
>> >
>> > While the compiler problems are being reworked and attempted to be
>> > solved, let's just drop the attribute to solve the issue now. Once it
>> > is resolved it can be added back.
>>
>> Could we instead wrap it in some #ifdef that' only true for clang build?
>> That would make the workaround more precise and self-documented. Even
>> better if it can trigger using clang version range and once a fixed
>> clang version is here, it can be updated to stay true for older clangs.
>
> It's not doing all that much good like this, let's just remove it for
> now until it does actually provide a benifit and not just crash the box :)
>
> This is only 1 function, that is used in only a very small number of
> callers. I do not think it will be missed.
Fair enough, added to the slab tree:
https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git/log/?h=for-5.17/fixup5
> thanks,
>
> greg k-h
>
next prev parent reply other threads:[~2022-02-18 18:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-18 13:13 [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller Greg Kroah-Hartman
2022-02-18 17:14 ` Vlastimil Babka
2022-02-18 17:57 ` Greg Kroah-Hartman
2022-02-18 18:54 ` Vlastimil Babka [this message]
2022-02-19 7:19 ` Greg Kroah-Hartman
2022-02-18 17:19 ` Nick Desaulniers
2022-02-19 23:58 ` Kees Cook
2022-02-18 18:47 ` David Rientjes
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