svn commit: r298677 - head/sys/kern

[Conrad E. Meyer]

Author: cem
Date: Tue Apr 26 23:58:55 2016
New Revision: 298677
URL: https://svnweb.freebsd.org/changeset/base/298677

Log:
  subr_mbpool: Don't free bogus pointer in error paths
  
  An mbpool is allocated with a contiguous array of mbpages.  Freeing an
  individual mbpage has never been valid.  Don't do it.
  
  This bug has been present since this code was introduced in r117624 (2003).
  
  Reported by:	Coverity
  CID:		1009687
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/sys/kern/subr_mbpool.c

Modified: head/sys/kern/subr_mbpool.c
==============================================================================
--- head/sys/kern/subr_mbpool.c	Tue Apr 26 23:23:44 2016	(r298676)
+++ head/sys/kern/subr_mbpool.c	Tue Apr 26 23:58:55 2016	(r298677)
@@ -210,16 +210,13 @@ mbp_alloc_page(struct mbpool *p)
 	pg = &p->pages[p->npages];
 
 	error = bus_dmamem_alloc(p->dmat, &pg->va, BUS_DMA_NOWAIT, &pg->map);
-	if (error != 0) {
-		free(pg, M_MBPOOL);
+	if (error != 0)
 		return;
-	}
 
 	error = bus_dmamap_load(p->dmat, pg->map, pg->va, p->page_size,
 	    mbp_callback, &pg->phy, 0);
 	if (error != 0) {
 		bus_dmamem_free(p->dmat, pg->va, pg->map);
-		free(pg, M_MBPOOL);
 		return;
 	}