On Wed, Jan 8, 2020 at 10:33 AM syzbot <syzbot+54fd8cca4b7226c94b8e@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 26467385 Add linux-next specific files for 20200107 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=10d44076e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2265a716722be976 > dashboard link: https://syzkaller.appspot.com/bug?extid=54fd8cca4b7226c94b8e > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+54fd8cca4b7226c94b8e@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: user-memory-access in memset include/linux/string.h:411 [inline] > BUG: KASAN: user-memory-access in video_get_user+0x67f/0x890 > drivers/media/v4l2-core/v4l2-ioctl.c:3053 > Write of size 512 at addr 00000000200001c0 by task syz-executor.2/1523 Confirmed and prepared a patch. Great find, this was a really nasty bug. Arnd > CPU: 1 PID: 1523 Comm: syz-executor.2 Not tainted > 5.5.0-rc5-next-20200107-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 > __kasan_report.cold+0x5/0x32 mm/kasan/report.c:510 > kasan_report+0x12/0x20 mm/kasan/common.c:641 > check_memory_region_inline mm/kasan/generic.c:185 [inline] > check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192 > memset+0x24/0x40 mm/kasan/common.c:108 > memset include/linux/string.h:411 [inline] > video_get_user+0x67f/0x890 drivers/media/v4l2-core/v4l2-ioctl.c:3053 > video_usercopy+0x21f/0x10b0 drivers/media/v4l2-core/v4l2-ioctl.c:3210 > video_ioctl2+0x2d/0x35 drivers/media/v4l2-core/v4l2-ioctl.c:3274 > v4l2_ioctl+0x1ac/0x230 drivers/media/v4l2-core/v4l2-dev.c:360 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45af49 > Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff > ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f5917b07c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49 > RDX: 00000000200001c0 RSI: 0000001002008914 RDI: 0000000000000006 > RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5917b086d4 > R13: 00000000004c2837 R14: 00000000004d8b30 R15: 00000000ffffffff > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
