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From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
To: bai <baijiaju1990@gmail.com>
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [BUG] video: fbdev: broadsheetfb: Possible null function pointers
Date: Thu, 26 Jul 2018 14:34:53 +0000	[thread overview]
Message-ID: <2568790.PcaMMF1rzM@amdc3058> (raw)
In-Reply-To: <cb43741a-83af-0b55-f53b-489bf7cb8b61@gmail.com>

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


  reply	other threads:[~2018-07-26 14:34 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20180726141748epcas1p28f6f11fea0152ed22113351e3a0affbc@epcas1p2.samsung.com>
2018-07-26 14:17 ` [BUG] video: fbdev: broadsheetfb: Possible null function pointers bai
2018-07-26 14:34   ` Bartlomiej Zolnierkiewicz [this message]
2018-07-27  1:49     ` Jia-Ju Bai
2018-07-27  8:06       ` Bartlomiej Zolnierkiewicz

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