Re: [PATCH] USB: core: Use `krealloc()` in `usb_cache_string()`

[Bence Csókás]

On 3/15/26 10:59, Bence Csókás wrote:
> Hi,
>
> On 3/15/26 10:47, Greg Kroah-Hartman wrote:
> > On Sun, Mar 15, 2026 at 10:40:48AM +0100, Bence Csókás wrote:
> > > > Also, how was this tested?
> > >
> > > I just compiled and booted it on my Arch box (with the original vendor
> > > config), an AthlonII X2 PC. I'm now typing this mail on a USB 
> > > keyboard and
> > > mouse under Plasma, running this kernel :) I also plugged in a pendrive,
> > > mounted it, `ls`'d the mount, unmounted, unplugged, and did this 2 more
> > > times.
> > >
> > > I realize I should probably put this info under the dashes. I'll 
> > > prepare a
> > > v2.
> >
> > Try looking at the USB strings in the device, as that's the path here
> > that is exercised.  Just using the device doesn't actually grab them
> > from the descriptor table.
>
> Sure.
>
>    $ sudo lsusb -vvv | grep iProduct
>    can't get debug descriptor: Resource temporarily unavailable
>      iProduct                2 OHCI PCI host controller
>      iProduct                2 HP USB Smart Card Keyboard
>    can't get device qualifier: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>      iProduct                2 USB OPTICAL MOUSE
>    can't get debug descriptor: Resource temporarily unavailable
>    can't get device qualifier: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>      iProduct                2 EHCI Host Controller
>      iProduct                2 EHCI Host Controller
>    can't get device qualifier: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>      iProduct                2 Disk 2.0
>      iProduct                2 EHCI Host Controller
>    can't get device qualifier: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>      iProduct                2 OHCI PCI host controller
>      iProduct                2 OHCI PCI host controller
>    can't get debug descriptor: Resource temporarily unavailable
>    can't get debug descriptor: Resource temporarily unavailable
>      iProduct                2 OHCI PCI host controller
>
> Are these -EAGAINs cause for concern?

It happens with the vendor kernel (6.19.8-arch1-1) too, so it's probably 
just some weirdness in my HW...

> > And sorry for the extra review, I'm a bit picky about this function, it
> > was my first contribution to Linux way back in 1999 or so, and happen to
> > know too much about USB descriptor strings :)
>
> A good review is a thorough review.
>
> > thanks,
> >
> > greg k-h
>
> Bence