Ok, applied to the netmap github repo. This fix will be published when Luigi does the next commit on FreeBSD.
Cheers, Vincenzo 2016-12-19 20:05 GMT+01:00 Navdeep Parhar <n...@freebsd.org>: > IFNET_RLOCK will work, thanks. > > Navdeep > > On Mon, Dec 19, 2016 at 3:21 AM, Vincenzo Maffione <v.maffi...@gmail.com> > wrote: >> Hi Navdeep, >> >> Indeed, we have reviewed the code, and we think it is ok to >> implement nm_os_ifnet_lock() with IFNET_RLOCK(), instead of using >> IFNET_WLOCK(). >> Since IFNET_RLOCK() results into sx_slock(), this should fix the issue. >> >> On FreeBSD, this locking is needed to protect a flag read by nm_iszombie(). >> However, on Linux the same lock is also needed to protect the call to >> the nm_hw_register() callback, so we prefer to have an "unified" >> locking scheme, i.e. always calling nm_hw_register under the lock. >> >> Does this make sense to you? Would it be easy for you to make a quick >> test by replacing IFNET_WLOCK with IFNET_RLOCK? >> >> Thanks, >> Vincenzo >> >> 2016-12-17 23:28 GMT+01:00 Navdeep Parhar <n...@freebsd.org>: >>> Luigi, Vincenzo, >>> >>> The last major update to netmap (r307394 and followups) broke cxgbe's >>> native netmap support. The problem is that netmap_hw_reg now holds an >>> rw_lock around the driver's netmap_on/off routines. It has always been >>> safe for the driver to sleep during these operations but now it panics >>> instead. >>> >>> Why is IFNET_WLOCK needed here? It seems like a regression to disallow >>> sleep on the control path. >>> >>> Regards, >>> Navdeep >>> >>> begin_synchronized_op with the following non-sleepable locks held: >>> exclusive rw ifnet_rw (ifnet_rw) r = 0 (0xffffffff8271d680) locked @ >>> /root/ws/head/sys/dev/netmap/netmap_freebsd.c:95 >>> stack backtrace: >>> #0 0xffffffff810837a5 at witness_debugger+0xe5 >>> #1 0xffffffff81084d88 at witness_warn+0x3b8 >>> #2 0xffffffff83ef2bcc at begin_synchronized_op+0x6c >>> #3 0xffffffff83f14beb at cxgbe_netmap_reg+0x5b >>> #4 0xffffffff809846f1 at netmap_hw_reg+0x81 >>> #5 0xffffffff809806de at netmap_do_regif+0x19e >>> #6 0xffffffff8098121d at netmap_ioctl+0x7ad >>> #7 0xffffffff8098682f at freebsd_netmap_ioctl+0x5f >> >> >> >> -- >> Vincenzo Maffione >> _______________________________________________ >> freebsd-net@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-net >> To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" -- Vincenzo Maffione _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
