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From: Steven Hartland <smh@FreeBSD.org>
Date: Thu, 14 Jan 2016 21:31:26 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r294040 - head/sys/boot/zfs
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Author: smh
Date: Thu Jan 14 21:31:26 2016
New Revision: 294040
URL: https://svnweb.freebsd.org/changeset/base/294040

Log:
  Prevent bogus compiler in ZFS boot code
  
  Silence a bogus compiler warning about indexing past the end of dn_bonus.
  
  The ZFS code ensures this is not possible but the compiler can't determine
  this so added an additional check to prevent this warning.
  
  Sponsored by:	Multiplay

Modified:
  head/sys/boot/zfs/zfsimpl.c

Modified: head/sys/boot/zfs/zfsimpl.c
==============================================================================
--- head/sys/boot/zfs/zfsimpl.c	Thu Jan 14 21:29:38 2016	(r294039)
+++ head/sys/boot/zfs/zfsimpl.c	Thu Jan 14 21:31:26 2016	(r294040)
@@ -2165,7 +2165,13 @@ zfs_lookup(const struct zfsmount *mount,
 				strcpy(&path[sb.st_size], p);
 			else
 				path[sb.st_size] = 0;
-			if (sb.st_size + sizeof(znode_phys_t) <= dn.dn_bonuslen) {
+			/*
+			 * Second test is purely to silence bogus compiler
+			 * warning about accessing past the end of dn_bonus.
+			 */
+			if (sb.st_size + sizeof(znode_phys_t) <=
+			    dn.dn_bonuslen && sizeof(znode_phys_t) <=
+			    sizeof(dn.dn_bonus)) {
 				memcpy(path, &dn.dn_bonus[sizeof(znode_phys_t)],
 					sb.st_size);
 			} else {