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[62.151.111.63]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4255d8acc4csm2320435f8f.16.2025.10.02.00.18.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Oct 2025 00:18:19 -0700 (PDT) From: Javier Martinez Canillas To: Thomas Zimmermann , Bhanu Seshu Kumar Valluri , Maarten Lankhorst , Maxime Ripard , David Airlie , Simona Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, skhan@linuxfoundation.org, david.hunter.linux@gmail.com, khalid@kernel.org Subject: Re: [PATCH] drm/ssd130x: Use kmalloc_array to prevent overflow of dynamic size calculation In-Reply-To: References: <20251002013312.67015-1-bhanuseshukumar@gmail.com> Date: Thu, 02 Oct 2025 09:18:17 +0200 Message-ID: <87zfa94vra.fsf@ocarina.mail-host-address-is-not-set> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Thomas Zimmermann writes: Hello Bhanu and Thomas, > Hi > > Am 02.10.25 um 03:33 schrieb Bhanu Seshu Kumar Valluri: >> Use kmalloc_array to avoid potential overflow during dynamic size calculation >> inside kmalloc. >> >> Signed-off-by: Bhanu Seshu Kumar Valluri >> --- The same patch was posted by another developer a couple of weeks ago and is now queued already in the drm-misc-next branch: https://cgit.freedesktop.org/drm/drm-misc/commit/?id=940dd88c5f5bdb1f3e19873a856a677ebada63a9 >> Note: >> Patch compiled successfully. >> No functionality change is intended. >> >> drivers/gpu/drm/solomon/ssd130x.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c >> index eec43d1a5595..8368f0ffbe1e 100644 >> --- a/drivers/gpu/drm/solomon/ssd130x.c >> +++ b/drivers/gpu/drm/solomon/ssd130x.c >> @@ -1498,7 +1498,7 @@ static int ssd130x_crtc_atomic_check(struct drm_crtc *crtc, >> if (ret) >> return ret; >> >> - ssd130x_state->data_array = kmalloc(ssd130x->width * pages, GFP_KERNEL); >> + ssd130x_state->data_array = kmalloc_array(ssd130x->width, pages, GFP_KERNEL); > > The first parameter is the number of elements. The second parameter is > the size of an individual element. So the arguments should be swapped. > Same for the other changes. > > I know it's nitpicking, but who knows what it'll be good for. Fun fact > is that even kmalloc_array mixes up both parameters internally. > You are right. I didn't notice this subtlety when reviewing mentioned patch that pushed to drm-misc-next. > Best regards > Thomas > > -- Best regards, Javier Martinez Canillas Core Platforms Red Hat