video: fbdev: sis: fix null ptr dereference
authorTom Rix <trix@redhat.com>
Wed, 5 Aug 2020 14:52:08 +0000 (07:52 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 29 Oct 2020 08:07:05 +0000 (09:07 +0100)
commitb1d39ad83acf90f48dc2265951542c670a115f9d
tree878fc549b167782b4589cf10574f43e745657648
parentcba6da8adcc0867ac3957fd1c726783c9385922c
video: fbdev: sis: fix null ptr dereference

[ Upstream commit ad6f93e9cd56f0b10e9b22e3e137d17a1a035242 ]

Clang static analysis reports this representative error

init.c:2501:18: warning: Array access (from variable 'queuedata') results
  in a null pointer dereference
      templ |= ((queuedata[i] & 0xc0) << 3);

This is the problem block of code

   if(ModeNo > 0x13) {
      ...
      if(SiS_Pr->ChipType == SIS_730) {
 queuedata = &FQBQData730[0];
      } else {
 queuedata = &FQBQData[0];
      }
   } else {

   }

queuedata is not set in the else block

Reviewing the old code, the arrays FQBQData730 and FQBQData were
used directly.

So hoist the setting of queuedata out of the if-else block.

Fixes: 544393fe584d ("[PATCH] sisfb update")
Signed-off-by: Tom Rix <trix@redhat.com>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200805145208.17727-1-trix@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/video/fbdev/sis/init.c