On 2021/04/15 0:39, Andrey Konovalov wrote: > On Wed, Apr 14, 2021 at 7:45 AM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >> 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. > Regarding ctrl_alt_del() problem, doing sh -c 'echo 0 > /proc/sys/kernel/ctrl-alt-del; echo $$ > /proc/sys/kernel/cad_pid' as root before start fuzzing might help. Also, with the command above, reproducer still triggers suspend operation which freezes userspace processes. This could possibly be one of causes for no output / lost connections. Try disabling freeze/suspend related configs? [ 60.881255][ T6280] usb 5-1: new high-speed USB device number 2 using dummy_hcd [ 61.260648][ T6280] usb 5-1: config 0 interface 0 altsetting 0 endpoint 0x81 has an invalid bInterval 0, changing to 7 [ 61.274056][ T6280] usb 5-1: New USB device found, idVendor=0926, idProduct=3333, bcdDevice= 0.40 [ 61.284700][ T6280] usb 5-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 61.289556][ T6280] usb 5-1: config 0 descriptor?? [ 61.780871][ T6280] keytouch 0003:0926:3333.0002: fixing up Keytouch IEC report descriptor [ 61.792015][ T6280] input: HID 0926:3333 as /devices/platform/dummy_hcd.0/usb5/5-1/5-1:0.0/0003:0926:3333.0002/input/input5 [ 61.871612][ T6280] keytouch 0003:0926:3333.0002: input,hidraw1: USB HID v0.00 Keyboard [HID 0926:3333] on usb-dummy_hcd.0-1/input0 [ 62.137706][ T6847] PM: suspend entry (s2idle) [ 62.147914][ T6847] Filesystems sync: 0.007 seconds [ 62.152031][ T6847] Freezing user space processes ... (elapsed 0.003 seconds) done. [ 62.158369][ T6847] OOM killer disabled. [ 62.159673][ T6847] Freezing remaining freezable tasks ... (elapsed 0.003 seconds) done. [ 62.167440][ T6847] vhci_hcd vhci_hcd.15: suspend vhci_hcd [ 62.169569][ T6847] vhci_hcd vhci_hcd.14: suspend vhci_hcd [ 62.171562][ T6847] vhci_hcd vhci_hcd.13: suspend vhci_hcd [ 62.173500][ T6847] vhci_hcd vhci_hcd.12: suspend vhci_hcd [ 62.175740][ T6847] vhci_hcd vhci_hcd.11: suspend vhci_hcd [ 62.177677][ T6847] vhci_hcd vhci_hcd.10: suspend vhci_hcd [ 62.179725][ T6847] vhci_hcd vhci_hcd.9: suspend vhci_hcd [ 62.181602][ T6847] vhci_hcd vhci_hcd.8: suspend vhci_hcd [ 62.183681][ T6847] vhci_hcd vhci_hcd.7: suspend vhci_hcd [ 62.185594][ T6847] vhci_hcd vhci_hcd.6: suspend vhci_hcd [ 62.187552][ T6847] vhci_hcd vhci_hcd.5: suspend vhci_hcd [ 62.189566][ T6847] vhci_hcd vhci_hcd.4: suspend vhci_hcd [ 62.191767][ T6847] vhci_hcd vhci_hcd.3: suspend vhci_hcd [ 62.193657][ T6847] vhci_hcd vhci_hcd.2: suspend vhci_hcd [ 62.195634][ T6847] vhci_hcd vhci_hcd.1: suspend vhci_hcd [ 62.197430][ T6847] vhci_hcd vhci_hcd.0: suspend vhci_hcd [ 62.249881][ T8] mptbase: ioc0: pci-suspend: pdev=0xffff888005495000, slot=0000:00:10.0, Entering operating state [D0]
