On Wed, 2018-03-07 at 11:24 -0800, Greg Hackmann wrote: > f7c83bcbfaf5 ("net: xfrm: use __this_cpu_read per-cpu helper") added > a > __this_cpu_read() call inside ipcomp_alloc_tfms(). Since this call > was > introduced, the rules around per-cpu accessors have been tightened > and > __this_cpu_read() cannot be used in a preemptible context. > > syzkaller reported this leading to the following kernel BUG while > fuzzing sendmsg: > > > Cc: sta...@vger.kernel.org
Hi Greg, thanks for this patch. 1) Please read Documentation/networking/netdev-FAQ.txt around line 133 2) If you believe this needs to be backported, you must provide a Fixes: tag to clearly identify commit that changed the behavior. Otherwise dozens of stable teams will have to figure out by themselves, wasting precious time. Thanks.