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Tue, 07 Oct 2025 15:23:33 -0700 (PDT) Received: from [192.168.1.14] ([38.175.187.108]) by smtp.gmail.com with ESMTPSA id e9e14a558f8ab-42d8b215dd6sm69116115ab.14.2025.10.07.15.23.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Oct 2025 15:23:32 -0700 (PDT) Message-ID: <10082c41-4302-4cb3-a2bf-788e59bad0c8@linuxfoundation.org> Date: Tue, 7 Oct 2025 16:23:32 -0600 Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] lib: cpu_rmap.c Refactor allocation size calculation in kzalloc() To: Mehdi Ben Hadj Khelifa , akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, david.hunter.linux@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org, Shuah Khan References: <20250930092327.27848-1-mehdi.benhadjkhelifa@gmail.com> Content-Language: en-US From: Shuah Khan In-Reply-To: <20250930092327.27848-1-mehdi.benhadjkhelifa@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/30/25 03:23, Mehdi Ben Hadj Khelifa wrote: > Wrap allocation size calculation in size_add() and size_mul() to avoid > any potential overflow. How did you find this problem and how did you test this change? > > Signed-off-by: Mehdi Ben Hadj Khelifa > --- > lib/cpu_rmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c > index f03d9be3f06b..18b2146a73d2 100644 > --- a/lib/cpu_rmap.c > +++ b/lib/cpu_rmap.c > @@ -36,7 +36,7 @@ struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags) > obj_offset = ALIGN(offsetof(struct cpu_rmap, near[nr_cpu_ids]), > sizeof(void *)); > > - rmap = kzalloc(obj_offset + size * sizeof(rmap->obj[0]), flags); > + rmap = kzalloc(size_add(obj_offset, size_mul(size, sizeof(rmap->obj[0]))), flags); > if (!rmap) > return NULL; > thanks, -- Shuah