Date: Wed, 21 Dec 2016 20:15:14 +0100 From: Vincenzo Maffione <v.maffione@gmail.com> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: Navdeep Parhar <np@freebsd.org>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Luigi Rizzo <luigi@freebsd.org>, Giuseppe Lettieri <g.lettieri@iet.unipi.it> Subject: Re: cxgbe's native netmap support broken since r307394 Message-ID: <CA%2B_eA9hAjK-i762t=ZCKqzrk5EDeEJM9gf%2BOAmDJqyUGrAYcFg@mail.gmail.com> In-Reply-To: <CAJ-VmomPW7%2BknAKbaLYjKXfgd=xAH3bYZi_LoxtNf5cuejJeJw@mail.gmail.com> References: <20161217222812.GA4979@ox> <CA%2B_eA9jxs3FatSLs8fseb%2BJSrqWrYkegDHyKA1q2QH=Q4_LbJQ@mail.gmail.com> <CAPFoGT9VoRWF306gBYgSKd2wi1rx3_2-yLpnxO98GyM0V-0Xog@mail.gmail.com> <CA%2B_eA9iUOZ9JLyx3bbDUZVc=cR6SqxReoOLRHUYQy-BU6Eb-UQ@mail.gmail.com> <CAJ-VmomPW7%2BknAKbaLYjKXfgd=xAH3bYZi_LoxtNf5cuejJeJw@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi, There is no commit related to that in the FreeBSD svn or git. The fix has been published to the github netmap repository here (branch master): https://github.com/luigirizzo/netmap What we should do is to import all the recent updates from the github into HEAD. I can prepare a patch for HEAD, if you wish. Just let me know. Cheers, Vincenzo 2016-12-20 21:45 GMT+01:00 Adrian Chadd <adrian.chadd@gmail.com>: > hi, > > What's the commit? We should get it into -HEAD asap. > > > -adrian > > > On 20 December 2016 at 01:25, Vincenzo Maffione <v.maffione@gmail.com> wrote: >> 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 <np@freebsd.org>: >>> IFNET_RLOCK will work, thanks. >>> >>> Navdeep >>> >>> On Mon, Dec 19, 2016 at 3:21 AM, Vincenzo Maffione <v.maffione@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 <np@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-unsubscribe@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-unsubscribe@freebsd.org" -- Vincenzo Maffione
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CA%2B_eA9hAjK-i762t=ZCKqzrk5EDeEJM9gf%2BOAmDJqyUGrAYcFg>