Re: [syzbot] [input?] [usb?] [mm?] INFO: rcu detected stall in vma_link_file

[Tetsuo Handa]

On 2024/10/16 16:14, Greg Kroah-Hartman wrote:
> On Wed, Oct 16, 2024 at 08:06:20AM +0100, Lorenzo Stoakes wrote:
>> + some people from USB/HID subsystem.
>>
>> This is really not looking mm-related, as for a second time we've asked
>> syzbot to re-run and for a second time it's not hit any mm-specific code -
>> I think this is misattributed - could somebody from the USB/HID side take a
>> look?
>>
>> It looks to be something that isn't reproduced by a specific C program but
>> by a syzkaller USB configuration [0]?
> 
> There's a lot of odd usb syzbot issues right now dealing with the dummy
> hcd controller, so maybe this is another one of them...

This is a printk() flooding stall triggered by SysRq-t.

 sched_show_task+0x3f0/0x5f0 kernel/sched/core.c:7557
 show_state_filter+0xee/0x320 kernel/sched/core.c:7627
 k_spec drivers/tty/vt/keyboard.c:667 [inline]
 k_spec+0xed/0x150 drivers/tty/vt/keyboard.c:656
 kbd_keycode drivers/tty/vt/keyboard.c:1522 [inline]
 kbd_event+0xcbd/0x17a0 drivers/tty/vt/keyboard.c:1541