svn commit: r324809 - head/sys/vm

[Mark Johnston]

Author: markj
Date: Fri Oct 20 21:13:19 2017
New Revision: 324809
URL: https://svnweb.freebsd.org/changeset/base/324809

Log:
  Free the right address range if kmem_back() fails in memguard_alloc().
  
  MFC after:	1 week
  Sponsored by:	Dell EMC Isilon

Modified:
  head/sys/vm/memguard.c

Modified: head/sys/vm/memguard.c
==============================================================================
--- head/sys/vm/memguard.c	Fri Oct 20 18:58:11 2017	(r324808)
+++ head/sys/vm/memguard.c	Fri Oct 20 21:13:19 2017	(r324809)
@@ -284,7 +284,7 @@ v2sizev(vm_offset_t va)
 void *
 memguard_alloc(unsigned long req_size, int flags)
 {
-	vm_offset_t addr;
+	vm_offset_t addr, origaddr;
 	u_long size_p, size_v;
 	int do_guard, rv;
 
@@ -328,7 +328,7 @@ memguard_alloc(unsigned long req_size, int flags)
 	for (;;) {
 		if (vmem_xalloc(memguard_arena, size_v, 0, 0, 0,
 		    memguard_cursor, VMEM_ADDR_MAX,
-		    M_BESTFIT | M_NOWAIT, &addr) == 0)
+		    M_BESTFIT | M_NOWAIT, &origaddr) == 0)
 			break;
 		/*
 		 * The map has no space.  This may be due to
@@ -343,11 +343,12 @@ memguard_alloc(unsigned long req_size, int flags)
 		memguard_wrap++;
 		memguard_cursor = memguard_base;
 	}
+	addr = origaddr;
 	if (do_guard)
 		addr += PAGE_SIZE;
 	rv = kmem_back(kmem_object, addr, size_p, flags);
 	if (rv != KERN_SUCCESS) {
-		vmem_xfree(memguard_arena, addr, size_v);
+		vmem_xfree(memguard_arena, origaddr, size_v);
 		memguard_fail_pgs++;
 		addr = (vm_offset_t)NULL;
 		goto out;