Re: [PATCH] 2.5.27 fix potential spinlocking race.

[Trond Myklebust <trond.myklebust@fys.uio.no>]

>>>>> " " == Linus Torvalds <torvalds@transmeta.com> writes:

     > Trond noticed that kfree_skb() can be called from a _non_ bh
     > context, ie process context. So it needs to protect itself
     > against other bh's on this CPU (which it wouldn't need to do if
     > it was only called from a bh context).

     > So it's exactly your "better context" that is at stake here.

Precisely. Not coming from a computer science background, the jargon
sometimes gets the better of me ;-)

I was playing around with ip_build_xmit_slow() looking at alternatives
for fixing the MSG_DONTWAIT fragmentation bug mentioned on this list a
couple of weeks ago, when I noticed that it can call kfree_skb() from
a process context. This again means that write_space() can get called
without being wrapped in a local_bh_disable()/local_bh_enable() -
style protection against softirqs.

Cheers,
  Trond