KASAN: global-out-of-bounds Read in precalculate_color

From: syzbot <syzbot+02d9172bf4c43104cd70@syzkaller.appspotmail.com>
To: hverkuil-cisco@xs4all.nl, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, mchehab@kernel.org,
	syzkaller-bugs@googlegroups.com, vivek.kasireddy@intel.com
Subject: KASAN: global-out-of-bounds Read in precalculate_color
Date: Thu, 28 Nov 2019 15:55:06 -0800	[thread overview]
Message-ID: <000000000000b6b450059870d703@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    d7688697 Merge tag 'for-linus' of git://git.kernel.org/pub..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=125118a2e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=121b4285bac421fe
dashboard link: https://syzkaller.appspot.com/bug?extid=02d9172bf4c43104cd70
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=119c517ae00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+02d9172bf4c43104cd70@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: global-out-of-bounds in precalculate_color+0x2154/0x2480  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:942
Read of size 1 at addr ffffffff884787bf by task vivid-000-vid-c/8948

CPU: 1 PID: 8948 Comm: vivid-000-vid-c Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x197/0x210 lib/dump_stack.c:118
  print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374
  __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
  kasan_report+0x12/0x20 mm/kasan/common.c:634
  __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129
  precalculate_color+0x2154/0x2480  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:942
  tpg_precalculate_colors drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:1093  
[inline]
  tpg_recalc+0x561/0x2850 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2118
  tpg_calc_text_basep+0xa1/0x290  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2136
  vivid_fillbuff+0x1a5f/0x3af0  
drivers/media/platform/vivid/vivid-kthread-cap.c:466
  vivid_thread_vid_cap_tick+0x8cf/0x2210  
drivers/media/platform/vivid/vivid-kthread-cap.c:727
  vivid_thread_vid_cap+0x5d8/0xa60  
drivers/media/platform/vivid/vivid-kthread-cap.c:866
  kthread+0x361/0x430 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the variable:
  sin+0x17f/0x280

Memory state around the buggy address:
  ffffffff88478680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffffffff88478700: 00 00 00 00 00 00 00 00 01 fa fa fa fa fa fa fa
> ffffffff88478780: 00 00 06 fa fa fa fa fa 04 fa fa fa fa fa fa fa
                                         ^
  ffffffff88478800: 05 fa fa fa fa fa fa fa 05 fa fa fa fa fa fa fa
  ffffffff88478880: 00 00 fa fa fa fa fa fa 00 00 00 00 00 00 fa fa
==================================================================

---
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