On Sat 05 Sep 2020 at 08:14, Jakub Kicinski <[email protected]> wrote: > On Thu, 3 Sep 2020 19:10:11 -0700 Cong Wang wrote: >> The following deadlock scenario is triggered by syzbot: >> >> Thread A: Thread B: >> tcf_idr_check_alloc() >> ... >> populate_metalist() >> rtnl_unlock() >> rtnl_lock() >> ... >> request_module() tcf_idr_check_alloc() >> rtnl_lock() >> >> At this point, thread A is waiting for thread B to release RTNL >> lock, while thread B is waiting for thread A to commit the IDR >> change with tcf_idr_insert() later. >> >> Break this deadlock situation by preloading ife modules earlier, >> before tcf_idr_check_alloc(), this is fine because we only need >> to load modules we need potentially. >> >> Reported-and-tested-by: [email protected] >> Fixes: 0190c1d452a9 ("net: sched: atomically check-allocate action") >> Cc: Jamal Hadi Salim <[email protected]> >> Cc: Vlad Buslov <[email protected]> > > Vlad, it'd have been nice to see your review tag here.
Reviewed. Sorry for the delay. > >> Cc: Jiri Pirko <[email protected]> >> Signed-off-by: Cong Wang <[email protected]> > > LGTM, applied and queued for stable, thank you Cong!
