From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Date: Thu, 26 Jul 2018 14:34:53 +0000 Subject: Re: [BUG] video: fbdev: broadsheetfb: Possible null function pointers Message-Id: <2568790.PcaMMF1rzM@amdc3058> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: bai Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org On Thursday, July 26, 2018 10:17:44 PM bai wrote: > In Linux-4.16, drivers/video/fbdev/broadsheetfb.c, > > 158. static void broadsheet_mmio_send_cmdargs(...) { > ...... > 163. par->board->mmio_write(...); > ...... > 166. par->board->mmio_write(...); > 167. } > > For x86 kernel configuration, I find that there is no assignment of the > function pointer ".mmio_write" in the kernel code. > So calling the function pointer in lines 163 and 166 may cause a null > pointer dereference. > > In this file, there are many calls to this function pointer... This is a platform driver and it won't be used on x86 (actually it is used only by single ARM PXA board). The dependency for FB_BROADSHEET in Kconfig file could be improved to i.e. depends on FB && (ARCH_PXA || COMPILE_TEST) but there is no bug there. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics