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From: Sean Bruno <sbruno@FreeBSD.org>
Date: Tue, 13 Jun 2017 19:32:23 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r319917 - head/sys/net
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Author: sbruno
Date: Tue Jun 13 19:32:23 2017
New Revision: 319917
URL: https://svnweb.freebsd.org/changeset/base/319917

Log:
  Plug mbuf leak in the busdma path of iflib.
  
  Submitted by:	Michael Tuexen <tuexen@freebsd.org>
  Reported by:	Drew Gallitin <gallatin@netflix.com>

Modified:
  head/sys/net/iflib.c

Modified: head/sys/net/iflib.c
==============================================================================
--- head/sys/net/iflib.c	Tue Jun 13 19:02:12 2017	(r319916)
+++ head/sys/net/iflib.c	Tue Jun 13 19:32:23 2017	(r319917)
@@ -2880,8 +2880,8 @@ iflib_busdma_load_mbuf_sg(iflib_txq_t txq, bus_dma_tag
 	if_ctx_t ctx;
 	if_shared_ctx_t		sctx;
 	if_softc_ctx_t		scctx;
-	int i, next, pidx, mask, err, maxsegsz, ntxd, count;
-	struct mbuf *m, *tmp, **ifsd_m, **mp;
+	int i, next, pidx, err, maxsegsz, ntxd, count;
+	struct mbuf *m, *tmp, **ifsd_m;
 
 	m = *m0;
 
@@ -2905,19 +2905,22 @@ iflib_busdma_load_mbuf_sg(iflib_txq_t txq, bus_dma_tag
 		if (err)
 			return (err);
 		ifsd_flags[pidx] |= TX_SW_DESC_MAPPED;
-		i = 0;
-		next = pidx;
-		mask = (txq->ift_size-1);
+		count = 0;
 		m = *m0;
 		do {
-			mp = &ifsd_m[next];
-			*mp = m;
+			if (__predict_false(m->m_len <= 0)) {
+				tmp = m;
+				m = m->m_next;
+				tmp->m_next = NULL;
+				m_free(tmp);
+				continue;
+			}
+			next = (pidx + count) & (ntxd-1);
+			MPASS(ifsd_m[next] == NULL);
+			ifsd_m[next] = m;
+			count++;
+			tmp = m;
 			m = m->m_next;
-			if (__predict_false((*mp)->m_len == 0)) {
-				m_free(*mp);
-				*mp = NULL;
-			} else
-				next = (pidx + i) & (ntxd-1);
 		} while (m != NULL);
 	} else {
 		int buflen, sgsize, max_sgsize;