linux-kernel - [syzbot] KMSAN: uninit-value in video

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Message-ID: <0000000000005ace4405bda4af71@google.com>
Date:   Tue, 16 Mar 2021 03:18:17 -0700
From:   syzbot <syzbot+142888ffec98ab194028@...kaller.appspotmail.com>
To:     arnd@...db.de, glider@...gle.com, hverkuil-cisco@...all.nl,
        laurent.pinchart@...asonboard.com, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org, mchehab@...nel.org,
        niklas.soderlund+renesas@...natech.se,
        sakari.ailus@...ux.intel.com, sergey.senozhatsky@...il.com,
        syzkaller-bugs@...glegroups.com, yepeilin.cs@...il.com
Subject: [syzbot] KMSAN: uninit-value in video_usercopy (2)

Hello,

syzbot found the following issue on:

HEAD commit:    29ad81a1 arch/x86: add missing include to sparsemem.h
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=102502dcd00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8b976581f6bd1e7d
dashboard link: https://syzkaller.appspot.com/bug?extid=142888ffec98ab194028
compiler:       Debian clang version 11.0.1-2
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+142888ffec98ab194028@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in check_array_args drivers/media/v4l2-core/v4l2-ioctl.c:3041 [inline]
BUG: KMSAN: uninit-value in video_usercopy+0x1631/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3315
CPU: 0 PID: 19595 Comm: syz-executor.4 Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 check_array_args drivers/media/v4l2-core/v4l2-ioctl.c:3041 [inline]
 video_usercopy+0x1631/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3315
 video_ioctl2+0x9f/0xb0 drivers/media/v4l2-core/v4l2-ioctl.c:3391
 v4l2_ioctl+0x255/0x290 drivers/media/v4l2-core/v4l2-dev.c:360
 v4l2_compat_ioctl32+0x2c6/0x370 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1248
 __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
 __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
 __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fec549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f55e65fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c050565d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Local variable ----sbuf@...eo_usercopy created at:
 video_usercopy+0xaa/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3285
 video_usercopy+0xaa/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3285
=====================================================
=====================================================
BUG: KMSAN: uninit-value in check_fmt+0x864/0x1070 drivers/media/v4l2-core/v4l2-ioctl.c:963
CPU: 0 PID: 19595 Comm: syz-executor.4 Tainted: G    B             5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 check_fmt+0x864/0x1070 drivers/media/v4l2-core/v4l2-ioctl.c:963
 v4l_prepare_buf+0xbf/0x1d0 drivers/media/v4l2-core/v4l2-ioctl.c:2107
 __video_do_ioctl+0x15cd/0x1d20 drivers/media/v4l2-core/v4l2-ioctl.c:2993
 video_usercopy+0x2313/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3345
 video_ioctl2+0x9f/0xb0 drivers/media/v4l2-core/v4l2-ioctl.c:3391
 v4l2_ioctl+0x255/0x290 drivers/media/v4l2-core/v4l2-dev.c:360
 v4l2_compat_ioctl32+0x2c6/0x370 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1248
 __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
 __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
 __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fec549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f55e65fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c050565d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Local variable ----sbuf@...eo_usercopy created at:
 video_usercopy+0xaa/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3285
 video_usercopy+0xaa/0x3d30 drivers/media/v4l2-core/v4l2-ioctl.c:3285
=====================================================


---
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