On 2018/7/26 22:34, Bartlomiej Zolnierkiewicz wrote:
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.
Thanks for the reply :)
So I want to submit a patch of updating Kconfig in
drivers/video/fbdev/Kconfig:
config FB_BROADSHEET
tristate "E-Ink Broadsheet/Epson S1D13521 controller support"
- depends on FB
+ depends on FB && (ARCH_PXA || COMPILE_TEST)
select FB_SYS_FILLRECT
select FB_SYS_COPYAREA
select FB_SYS_IMAGEBLIT
select FB_SYS_FOPS
select FB_DEFERRED_IO
Do you think it is okay?
Best wishes,
Jia-Ju Bai
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