On Fri, Feb 10, 2017 at 10:02 AM, Eric Dumazet <eric.duma...@gmail.com> wrote: > On Fri, 2017-02-10 at 09:59 -0800, Eric Dumazet wrote: >> On Fri, 2017-02-10 at 09:49 -0800, Cong Wang wrote: >> > On Thu, Feb 9, 2017 at 7:23 PM, Eric Dumazet <eric.duma...@gmail.com> >> > wrote: >> > > On Thu, 2017-02-09 at 19:19 -0800, Eric Dumazet wrote: >> > > >> > >> More likely the bug is in fanout_add(), with a buggy sequence in error >> > >> case, and not correct locking. >> > >> >> > >> kfree(po->rollover); >> > >> po->rollover = NULL; >> > >> >> > >> Two cpus entering fanout_add() (using the same af_packet socket, >> > >> syzkaller courtesy...) might both see po->fanout being NULL. >> > >> >> > >> Then they grab the mutex. Too late... >> > > >> > > Patch could be : >> > > >> > >> > For me, clearly the data structure that use-after-free'd is struct sock >> > rather than struct packet_rollover. >> >> Fine. But your patch makes absolutely no sense. > > At least, Anoob patch is making a step into the right direction ;) > > https://patchwork.ozlabs.org/patch/726532/ >
Yeah, but still looks like a different one with the one Dmitry reported.