On Tue, 5 Nov 2024 11:39:59 -0500 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Mon, Nov 04, 2024 at 08:00:07PM -0800, Andrew Morton wrote: > > On Wed, 30 Oct 2024 21:54:22 -0700 syzbot <syzbot+ccc0e1cfdb72b664f0d8@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > Hello, > > > > > > syzbot found the following issue on: > > > > Thanks. I'm suspecting some USB issue - fault injection was used to > > trigger a memory allocation failure and dec_usb_memory_use_count() ended > > up freeing an in-use page. Could USB folks please have a look? > > Andrew, I'm not sure what to look for. Thanks for looking. > Can you read through > usbdev_mmap() in drivers/usb/core/devio.c, along with the four short > routines preceding it, and let us know if anything seems obviously > wrong? All I see is lots of USB code which I don't understand ;) It seems odd that usbdev_mmap() calls dec_usb_memory_use_count() on some error paths, but goes direct to usbfs_decrease_memory_usage() on others. Did you try running the "C reproducer"?
