[lvm-devel] [PATCH 2/4] Fix access to released memory
Zdenek Kabelac
zkabelac at redhat.com
Thu Mar 24 11:16:35 UTC 2011
Somewhat tricky part of the code.
Invalid primary_vginfo was supposed to move all its lvmcache_info to
orphan_vginfo - however it has called _drop_vginfo() inside the loop
that remove primary_vginfo itself - thus made the loop using released
memory.
Patch used _vginfo_detach_info() instead and call _drop_vginfo after
this whole loop is finished.
Here is valgrind trace it should be fixed:
Invalid read of size 8
at 0x41E960: _lvmcache_update_vgname (lvmcache.c:1229)
by 0x41EF86: lvmcache_update_vgname_and_id (lvmcache.c:1360)
by 0x441393: _text_read (text_label.c:329)
by 0x442221: label_read (label.c:289)
by 0x41CF92: lvmcache_label_scan (lvmcache.c:635)
by 0x45B303: _vg_read_by_vgid (metadata.c:3342)
by 0x45B4A6: lv_from_lvid (metadata.c:3381)
by 0x41B555: lv_activation_filter (activate.c:1346)
by 0x415868: do_activate_lv (lvm-functions.c:343)
by 0x415E8C: do_lock_lv (lvm-functions.c:532)
by 0x40FD5F: do_command (clvmd-command.c:120)
by 0x413D7B: process_local_command (clvmd.c:1686)
Address 0x63eba10 is 16 bytes inside a block of size 160 free'd
at 0x4C2756E: free (vg_replace_malloc.c:366)
by 0x41DE70: _free_vginfo (lvmcache.c:980)
by 0x41DEDA: _drop_vginfo (lvmcache.c:998)
by 0x41E854: _lvmcache_update_vgname (lvmcache.c:1238)
by 0x41EF86: lvmcache_update_vgname_and_id (lvmcache.c:1360)
by 0x441393: _text_read (text_label.c:329)
by 0x442221: label_read (label.c:289)
by 0x41CF92: lvmcache_label_scan (lvmcache.c:635)
by 0x45B303: _vg_read_by_vgid (metadata.c:3342)
by 0x45B4A6: lv_from_lvid (metadata.c:3381)
by 0x41B555: lv_activation_filter (activate.c:1346)
by 0x415868: do_activate_lv (lvm-functions.c:343)
problematic line:
dm_list_iterate_items_safe(info2, info3, &primary_vginfo->infos)
Signed-off-by: Zdenek Kabelac <zkabelac at redhat.com>
---
lib/cache/lvmcache.c | 24 ++++++++++++++----------
1 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index 4e2e158..ee7d278 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -1107,17 +1107,17 @@ static int _lvmcache_update_vgname(struct lvmcache_info *info,
* Otherwise we risk bogus warnings of duplicate VGs.
*/
while ((primary_vginfo = vginfo_from_vgname(vgname, NULL)) &&
- _scanning_in_progress && _vginfo_is_invalid(primary_vginfo))
+ _scanning_in_progress && _vginfo_is_invalid(primary_vginfo)) {
+ orphan_vginfo = vginfo_from_vgname(primary_vginfo->fmt->orphan_vg_name, NULL);
+ if (!orphan_vginfo) {
+ log_error(INTERNAL_ERROR "Orphan vginfo %s lost from cache.",
+ primary_vginfo->fmt->orphan_vg_name);
+ dm_free(vginfo->vgname);
+ dm_free(vginfo);
+ return 0;
+ }
dm_list_iterate_items_safe(info2, info3, &primary_vginfo->infos) {
- orphan_vginfo = vginfo_from_vgname(primary_vginfo->fmt->orphan_vg_name, NULL);
- if (!orphan_vginfo) {
- log_error(INTERNAL_ERROR "Orphan vginfo %s lost from cache.",
- primary_vginfo->fmt->orphan_vg_name);
- dm_free(vginfo->vgname);
- dm_free(vginfo);
- return 0;
- }
- _drop_vginfo(info2, primary_vginfo);
+ _vginfo_detach_info(info2);
_vginfo_attach_info(orphan_vginfo, info2);
if (info2->mdas.n)
sprintf(mdabuf, " with %u mdas",
@@ -1129,6 +1129,10 @@ static int _lvmcache_update_vgname(struct lvmcache_info *info,
vgname, orphan_vginfo->vgid[0] ? " (" : "",
orphan_vginfo->vgid[0] ? orphan_vginfo->vgid : "",
orphan_vginfo->vgid[0] ? ")" : "", mdabuf);
+ }
+
+ if (!_drop_vginfo(NULL, primary_vginfo))
+ return_0;
}
if (!_insert_vginfo(vginfo, vgid, vgstatus, creation_host,
--
1.7.4.1
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