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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Vlastimil Babka <vbabka@suse.cz>
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: Sat, 19 Feb 2022 08:19:02 +0100	[thread overview]
Message-ID: <YhCZ5m+uw/xqS9W2@kroah.com> (raw)
In-Reply-To: <c237f6d1-4219-0e6d-6aca-9c29d060bb4f@suse.cz>

On Fri, Feb 18, 2022 at 07:54:14PM +0100, Vlastimil Babka wrote:
> 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!


  reply	other threads:[~2022-02-19  7:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-18 13:13 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
2022-02-19  7:19       ` Greg Kroah-Hartman [this message]
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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