KMSAN: uninit-value in legacy_dvb_usb_read_remote_control

From: syzbot <syzbot+2cd8c5db4a85f0a04142@syzkaller.appspotmail.com>
To: glider@google.com, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, mchehab@kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: KMSAN: uninit-value in legacy_dvb_usb_read_remote_control
Date: Sat, 12 Dec 2020 09:43:10 -0800	[thread overview]
Message-ID: <000000000000447ae005b647f1df@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    73d62e81 kmsan: random: prevent boot-time reports in _mix_..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=12d97ccb500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=eef728deea880383
dashboard link: https://syzkaller.appspot.com/bug?extid=2cd8c5db4a85f0a04142
compiler:       clang version 11.0.0 (https://github.com/llvm/llvm-project.git ca2dcbd030eadbf0aa9b660efe864ff08af6e18b)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=100658c5500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16e4cb9b500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2cd8c5db4a85f0a04142@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in legacy_dvb_usb_read_remote_control+0x3b8/0x730 drivers/media/usb/dvb-usb/dvb-usb-remote.c:129
CPU: 0 PID: 8393 Comm: kworker/0:5 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events legacy_dvb_usb_read_remote_control
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 legacy_dvb_usb_read_remote_control+0x3b8/0x730 drivers/media/usb/dvb-usb/dvb-usb-remote.c:129
 process_one_work+0x121c/0x1fc0 kernel/workqueue.c:2272
 worker_thread+0x10cc/0x2740 kernel/workqueue.c:2418
 kthread+0x51c/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Local variable ----state@legacy_dvb_usb_read_remote_control created at:
 legacy_dvb_usb_read_remote_control+0x68/0x730 drivers/media/usb/dvb-usb/dvb-usb-remote.c:120
 legacy_dvb_usb_read_remote_control+0x68/0x730 drivers/media/usb/dvb-usb/dvb-usb-remote.c:120
=====================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8393 Comm: kworker/0:5 Tainted: G    B             5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events legacy_dvb_usb_read_remote_control
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 panic+0x4c8/0xea7 kernel/panic.c:231
 kmsan_report+0x1da/0x1e0 mm/kmsan/kmsan_report.c:141
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 legacy_dvb_usb_read_remote_control+0x3b8/0x730 drivers/media/usb/dvb-usb/dvb-usb-remote.c:129
 process_one_work+0x121c/0x1fc0 kernel/workqueue.c:2272
 worker_thread+0x10cc/0x2740 kernel/workqueue.c:2418
 kthread+0x51c/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Kernel Offset: disabled
Rebooting in 86400 seconds..

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