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([2a01:e0a:9b4:d000:c3c5:df83:3a33:2c51]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49764d8e81asm64980995e9.7.2026.07.29.08.18.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Jul 2026 08:18:44 -0700 (PDT) Message-ID: Date: Wed, 29 Jul 2026 17:18:41 +0200 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 3/4] drm/log: Fix infinite loop when scale is too large for display To: oushixiong1025@163.com Cc: Javier Martinez Canillas , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Shixiong Ou References: <20260729084815.692944-1-oushixiong1025@163.com> Content-Language: en-US, fr From: Jocelyn Falempe In-Reply-To: <20260729084815.692944-1-oushixiong1025@163.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 29/07/2026 10:48, oushixiong1025@163.com wrote: > From: Shixiong Ou > > When scale is large enough that scaled_font exceeds the display > dimensions, rows or columns become 0. A columns value of 0 causes > an infinite loop in drm_log_draw_kmsg_record() because the loop > never decrements len. > > Check for zero rows/columns in drm_log_setup_modeset() and return > an error, cleaning up the already allocated buffer to avoid a leak. Thanks, it looks good to me. Reviewed-by: Jocelyn Falempe > > Signed-off-by: Shixiong Ou > --- > drivers/gpu/drm/clients/drm_log.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/gpu/drm/clients/drm_log.c b/drivers/gpu/drm/clients/drm_log.c > index a04f651e8265..63577aeb705c 100644 > --- a/drivers/gpu/drm/clients/drm_log.c > +++ b/drivers/gpu/drm/clients/drm_log.c > @@ -240,6 +240,12 @@ static int drm_log_setup_modeset(struct drm_client_dev *client, > scanout->scaled_font_w = scanout->font->width * scale; > scanout->rows = height / scanout->scaled_font_h; > scanout->columns = width / scanout->scaled_font_w; > + if (!scanout->rows || !scanout->columns) { > + drm_client_buffer_delete(scanout->buffer); > + scanout->buffer = NULL; > + mode_set->fb = NULL; > + return -EINVAL; > + } > scanout->front_color = drm_draw_color_from_xrgb8888(0xffffff, format); > scanout->prefix_color = drm_draw_color_from_xrgb8888(0x4e9a06, format); > return 0;