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Mon, 20 Oct 2025 13:06:13 -0700 (PDT) Received: from [192.168.1.14] ([38.175.187.108]) by smtp.gmail.com with ESMTPSA id e9e14a558f8ab-430d06f9ff0sm33307335ab.3.2025.10.20.13.06.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Oct 2025 13:06:12 -0700 (PDT) Message-ID: Date: Mon, 20 Oct 2025 14:06:12 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/tiny: Use kmalloc_array() instead of kmalloc() To: Jani Nikula , Mehdi Ben Hadj Khelifa , Thomas Zimmermann , Greg KH Cc: lanzano.alex@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@gmail.com, simona@ffwll.ch, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, david.hunter.linux@gmail.com, khalid@kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, Shuah Khan References: <20251019151247.171558-1-mehdi.benhadjkhelifa@gmail.com> <2025101910-dipper-suburb-1755@gregkh> <02e617bec795d2ef371069f2d5fb954dfb31a450@intel.com> Content-Language: en-US From: Shuah Khan In-Reply-To: <02e617bec795d2ef371069f2d5fb954dfb31a450@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/20/25 03:50, Jani Nikula wrote: > On Sun, 19 Oct 2025, Mehdi Ben Hadj Khelifa wrote: >> On 10/19/25 3:47 PM, Thomas Zimmermann wrote: >>> Hi >>> >>> Am 19.10.25 um 16:34 schrieb Greg KH: >>>> On Sun, Oct 19, 2025 at 04:12:28PM +0100, Mehdi Ben Hadj Khelifa wrote: >>>>> Replace kmalloc() with kmalloc_array() to correctly >>>>> handle array allocations and benefit from built-in overflow checking[1]. >>>>> >>>>> [1]:https://docs.kernel.org/process/deprecated.html >>>>> >>>>> Signed-off-by: Mehdi Ben Hadj Khelifa >>>>> --- >>>>>   drivers/gpu/drm/tiny/repaper.c | 2 +- >>>>>   1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/gpu/drm/tiny/repaper.c b/drivers/gpu/drm/tiny/ >>>>> repaper.c >>>>> index 4824f863fdba..290132c24ff9 100644 >>>>> --- a/drivers/gpu/drm/tiny/repaper.c >>>>> +++ b/drivers/gpu/drm/tiny/repaper.c >>>>> @@ -534,7 +534,7 @@ static int repaper_fb_dirty(struct >>>>> drm_framebuffer *fb, const struct iosys_map * >>>>>       DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id, >>>>>             epd->factored_stage_time); >>>>> -    buf = kmalloc(fb->width * fb->height / 8, GFP_KERNEL); >>>>> +    buf = kmalloc_array(fb->height / 8, fb->width, GFP_KERNEL); > > Also worth emphasizing that this is wildly wrong for any height that is > not a multiple of 8. > > And I thought I shot down a similar patch not long ago. > > Is there some tool that suggests doing this? Fix the tool instead > please. > They are documented in https://docs.kernel.org/process/deprecated.html Mu understanding is that this document lists deprecates APIs so people don't keep adding new ones. I didn't get the impression that we are supposed to go delete them from the kernel and cause a churn. thanks, -- Shuah