On Wed, Apr 14, 2021 at 7:45 AM Dmitry Vyukov <dvyu...@google.com> wrote: > > On Tue, Apr 13, 2021 at 11:27 PM syzbot > <syzbot+9ce030d4c89856b27...@syzkaller.appspotmail.com> wrote: > > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 89698bec Merge tag 'm68knommu-for-v5.12-rc7' of git://git... > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=1243fcfed00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=b234ddbbe2953747 > > dashboard link: https://syzkaller.appspot.com/bug?extid=9ce030d4c89856b27619 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=173e92fed00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1735da2ed00000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+9ce030d4c89856b27...@syzkaller.appspotmail.com > > > > output_len: 0x000000000e74eb68 > > kernel_total_size: 0x000000000f226000 > > needed_size: 0x000000000f400000 > > trampoline_32bit: 0x000000000009d000 > > Decompressing Linux... Parsing ELF... done. > > Booting the kernel. > > +linux-input > > The reproducer connects some USB HID device and communicates with the driver. > Previously we observed reboots because HID devices can trigger reboot > SYSRQ, but we disable it with "CONFIG_MAGIC_SYSRQ is not set". > How else can a USB device reboot the machine? Is it possible to disable it? > I don't see any direct includes of <linux/reboot.h> in drivers/usb/*
This happens when a keyboard sends the Ctrl+Alt+Del sequence, see fn_boot_it()->ctrl_alt_del() in drivers/tty/vt/keyboard.c. There was a patchset by Tetsuo [1] to suppress this, but I think it was abandoned. (This reminds of a somewhat related syzkaller issue: https://github.com/google/syzkaller/issues/1824; it relies on a similar reproducer.) [1] https://groups.google.com/g/syzkaller/c/7wCmrGlLgm0/m/5yG6HVtbBQAJ
