Date: Sat, 17 Dec 2016 14:28:27 -0800 From: Navdeep Parhar <np@FreeBSD.org> To: v.maffione@gmail.com, luigi@FreeBSD.org, freebsd-net@FreeBSD.org Subject: cxgbe's native netmap support broken since r307394 Message-ID: <20161217222812.GA4979@ox>
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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
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