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Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vv63I-00000000OwB-1kXC; Wed, 25 Feb 2026 03:59:08 +0000 Date: Wed, 25 Feb 2026 03:59:08 +0000 From: Matthew Wilcox To: Kees Cook Cc: Vlastimil Babka , Vlastimil Babka , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH] slab: Saturate to SIZE_MAX for allocation size overflows Message-ID: References: <20260225013954.work.319-kees@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260225013954.work.319-kees@kernel.org> X-Rspamd-Queue-Id: 6660C1A0011 X-Stat-Signature: zd6ynecypppuqep5ougitccu4kidsdg8 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1771991956-179511 X-HE-Meta: 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 7LpfJE68 88bRp13/iL0WiavU1UOoGpj/gl8GhiymUfcef1pDemQA9nJDdzFKSuFuqVbIhAvC6LiT9xvVotDWP4OsMk+EhiBawSSvf3LAY6lwDgeDerbnUdeA9+ruS783qxrKkRGstWpLYSTzhc5RNmVIJ7PCzitekvStbTyycQtaeRjio9mcTpsnYdgnUTQLWPejM/zjd4DeWIq3q8Xys8xsjehCMW0Vo7LTfywP4A6uxC/hbOkv5y+VmtlAMvPFfii66LOH3ogea4haKZOgyp54Kt4fNB+RvG9H2UQruJFBJHFPOJ96AtpSo0lxo7mc0LKH+rP5APGlb Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Feb 24, 2026 at 05:40:02PM -0800, Kees Cook wrote: > +++ b/include/linux/slab.h > @@ -1105,7 +1105,7 @@ static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t siz > size_t bytes; > > if (unlikely(check_mul_overflow(n, size, &bytes))) > - return NULL; > + bytes = SIZE_MAX; > return kmalloc_noprof(bytes, flags); Wouldn't this be better written as: return kmalloc_noprof(size_mul(n, size), flags); (etc)