Greg KH gregkh@linuxfoundation.org wrote:

On Mon, Nov 15, 2021 at 09:39:53AM -0800, Greg Thelen wrote:

...

The patch titled ("perf/core: Avoid put_page() when GUP fails") has been merged into linus/master as commit 4716023a8f6a0f4a28047f14dd7ebdc319606b84.

The patch fixes an issue present in all v4.14+ kernels that can cause page reference count underflow, which can lead to unintentional page sharing.

The patch did not have cc: stable footer, so I'm manually requesting -stable inclusion into v4.14+.

There are some trivial conflicts in older kernels. I'd be happy to review/test, if that's useful.

Please provide working versions for 4.14, 4.19, and 5.4. The others kernels applied just fine.

thanks,

greg k-h

Done. Backported and tested on stable 4.14-y, 4.19-y, and 5.4-y: https://lore.kernel.org/stable/20211122171825.1582436-1-gthelen@google.com/ https://lore.kernel.org/stable/20211122171824.1582407-1-gthelen@google.com/ https://lore.kernel.org/stable/20211122171818.1582357-1-gthelen@google.com/