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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43ead401ca0sm6144220f8f.36.2026.04.15.11.38.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2026 11:38:54 -0700 (PDT) Date: Wed, 15 Apr 2026 19:38:52 +0100 From: David Laight To: Andy Shevchenko Cc: Thorsten Blum , Andrew Morton , Kees Cook , Andy Shevchenko , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] lib/string_helpers: drop redundant allocation in kasprintf_strarray Message-ID: <20260415193852.3171301b@pumpkin> In-Reply-To: References: <20260415122542.370926-4-thorsten.blum@linux.dev> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 15 Apr 2026 17:42:41 +0300 Andy Shevchenko wrote: > On Wed, Apr 15, 2026 at 02:25:43PM +0200, Thorsten Blum wrote: > > kasprintf_strarray() returns an array of N strings and kfree_strarray() > > also frees N entries. However, kasprintf_strarray() currently allocates > > N+1 char pointers. Allocate exactly N pointers instead of N+1. > > > > Also update the kernel-doc for @n. > > Have you checked all current users that they do not rely on the NULL terminated > array? > > Note, that was done on purpose that once allocated it can allow user > to drop the track of the number of strings and rely on NULL terminator. > I.o.w. the number of strings may be just a local variable somewhere > where kasprintf_strarray() is called. > > I tend to NAK this change, rather you can update kernel-doc to explain > why it's done this way (see above). > It isn't as though it is going to make much difference to the memory footprint. Allocating an extra trailing NULL is just a bit safer. David