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Fri, 13 Jun 2025 17:56:48 -0700 (PDT) From: Alex Guo To: deller@gmx.de Cc: alexguo1023@gmail.com, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] fbdev: tdfxfb: Fix potential divide by zero Date: Fri, 13 Jun 2025 20:56:46 -0400 Message-Id: <20250614005646.3117593-1-alexguo1023@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Variable var->pixclock can be set by user. In case it equals to zero, divide by zero would occur in tdfxfb_check_var. Similar crashes have happened in other fbdev drivers. We fix this by checking whether 'pixclock' is zero. Signed-off-by: Alex Guo --- drivers/video/fbdev/tdfxfb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/video/fbdev/tdfxfb.c b/drivers/video/fbdev/tdfxfb.c index 51ebe78359ec..2100857fa7b3 100644 --- a/drivers/video/fbdev/tdfxfb.c +++ b/drivers/video/fbdev/tdfxfb.c @@ -495,6 +495,9 @@ static int tdfxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) return -EINVAL; } } + + if (var->pixclock <= KHZ2PICOS(par->max_pixclock)) + var->pixclock = KHZ2PICOS(par->max_pixclock) + 1; if (PICOS2KHZ(var->pixclock) > par->max_pixclock) { DPRINTK("pixclock too high (%ldKHz)\n",