On Fri, Dec 01, 2023 at 10:19:35AM +0100, Daniel Borkmann wrote:

On 11/30/23 4:15 PM, Willem de Bruijn wrote:

quoted

Daniel Borkmann wrote:

quoted

On 11/30/23 3:20 PM, Greg Kroah-Hartman wrote:

quoted

In some potential instances the reference count on struct packet_sock
could be saturated and cause overflows which gets the kernel a bit
confused.  To prevent this, move to a 64bit atomic reference count to
prevent the possibility of this type of overflow.

Because we can not handle saturation, using refcount_t is not possible
in this place.  Maybe someday in the future if it changes could it be
used.

Original version from Daniel after I did it wrong, I've provided a
changelog.

Reported-by: "The UK's National Cyber Security Centre (NCSC)" <redacted>
Cc: stable <stable@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Thanks!

Acked-by: Daniel Borkmann <daniel@iogearbox.net>

Acked-by: Willem de Bruijn <willemb@google.com>

There was feedback from Linus that switching to atomic_long_t is better
choice so that it doesn't penalize 32-bit architectures. Will post a v2
today.

Thanks, makes sense to do it that way.

greg k-h