On Mon, 2016-06-27 at 10:51 -0400, David Miller wrote: > From: Eric Dumazet <eric.duma...@gmail.com> > Date: Sat, 25 Jun 2016 18:09:35 +0200 > > > From: Eric Dumazet <eduma...@google.com> > > > > Some arches have virtually mapped kernel stacks, or will soon have. > > > > tcp_md5_hash_header() uses an automatic variable to copy tcp header > > before mangling th->check and calling crypto function, which might > > be problematic on such arches. > > > > So use percpu storage as we already do for the pseudo header, > > and reduce number of crypto functions calls, as these headers > > are ridiculously small. > > > > Signed-off-by: Eric Dumazet <eduma...@google.com> > > Reported-by: Andy Lutomirski <l...@amacapital.net> > > --- > > I am not sure the md5 crypto functions have a problem with data backed > > in virtually mapped stacks, but this patch seems to remove the doubt. > > In a non-SMP build this storage will be in the kernel image itself. > > And this violates the crypto layer's requirements. > > It has to be memory taken from the page allocator or kmalloc. So > before vmalloc'd stacks, the current code is perfectly fine. And > with vmalloc'd stacks this patch trades one bug for another.
OK, so lets simply use kmalloc() allocated storage instead of percpu.
