Date: Mon, 17 Aug 2015 19:06:15 +0000 (UTC) From: Luiz Otavio O Souza <loos@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r286859 - stable/10/sys/net Message-ID: <201508171906.t7HJ6FLn086032@repo.freebsd.org>
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Author: loos Date: Mon Aug 17 19:06:14 2015 New Revision: 286859 URL: https://svnweb.freebsd.org/changeset/base/286859 Log: MFC r286260: Remove the mtx_sleep() from the kqueue f_event filter. The filter is called from the network hot path and must not sleep. The filter runs with the descriptor lock held and does not manipulate the buffers, so it is not necessary sleep when the hold buffer is in use. Just ignore the hold buffer contents when it is being copied to user space (when hold buffer in use is set). This fix the "Sleeping thread owns a non-sleepable lock" panic when the userland thread is too busy reading the packets from bpf(4). PR: 200323 Sponsored by: Rubicon Communications (Netgate) Modified: stable/10/sys/net/bpf.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/net/bpf.c ============================================================================== --- stable/10/sys/net/bpf.c Mon Aug 17 19:02:23 2015 (r286858) +++ stable/10/sys/net/bpf.c Mon Aug 17 19:06:14 2015 (r286859) @@ -1984,10 +1984,10 @@ filt_bpfread(struct knote *kn, long hint ready = bpf_ready(d); if (ready) { kn->kn_data = d->bd_slen; - while (d->bd_hbuf_in_use) - mtx_sleep(&d->bd_hbuf_in_use, &d->bd_lock, - PRINET, "bd_hbuf", 0); - if (d->bd_hbuf) + /* + * Ignore the hold buffer if it is being copied to user space. + */ + if (!d->bd_hbuf_in_use && d->bd_hbuf) kn->kn_data += d->bd_hlen; } else if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { callout_reset(&d->bd_callout, d->bd_rtout,
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