Messages in this thread |  | | Date | Wed, 28 Sep 2022 10:13:12 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 01/16] slab: Remove __malloc attribute from realloc functions |
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On Wed, Sep 28, 2022 at 09:26:15AM +0200, Geert Uytterhoeven wrote: > Hi Kees, > > On Fri, Sep 23, 2022 at 10:35 PM Kees Cook <keescook@chromium.org> wrote: > > The __malloc attribute should not be applied to "realloc" functions, as > > the returned pointer may alias the storage of the prior pointer. Instead > > of splitting __malloc from __alloc_size, which would be a huge amount of > > churn, just create __realloc_size for the few cases where it is needed. > > > > Additionally removes the conditional test for __alloc_size__, which is > > always defined now. > > > > Cc: Christoph Lameter <cl@linux.com> > > Cc: Pekka Enberg <penberg@kernel.org> > > Cc: David Rientjes <rientjes@google.com> > > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Vlastimil Babka <vbabka@suse.cz> > > Cc: Roman Gushchin <roman.gushchin@linux.dev> > > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> > > Cc: Marco Elver <elver@google.com> > > Cc: linux-mm@kvack.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > Thanks for your patch, which is now commit 63caa04ec60583b1 ("slab: > Remove __malloc attribute from realloc functions") in next-20220927. > > Noreply@ellerman.id.au reported all gcc8-based builds to fail > (e.g. [1], more at [2]): > > In file included from <command-line>: > ./include/linux/percpu.h: In function ‘__alloc_reserved_percpu’: > ././include/linux/compiler_types.h:279:30: error: expected > declaration specifiers before ‘__alloc_size__’ > #define __alloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) __malloc > ^~~~~~~~~~~~~~ > ./include/linux/percpu.h:120:74: note: in expansion of macro ‘__alloc_size’ > [...] > > It's building fine with e.g. gcc-9 (which is my usual m68k cross-compiler). > Reverting this commit on next-20220927 fixes the issue. > > [1] http://kisskb.ellerman.id.au/kisskb/buildresult/14803908/ > [2] http://kisskb.ellerman.id.au/kisskb/head/1bd8b75fe6adeaa89d02968bdd811ffe708cf839/
Eek! Thanks for letting me know. I'm confused about this -- __alloc_size__ wasn't optional in compiler_attributes.h -- but obviously I broke something! I'll go figure this out.
-Kees
-- Kees Cook
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