autofs-5.0.5 - fix out of order locking in readmap
From: Ian Kent <raven@themaw.net>
When re-reading the master map and a mount lookup for a particular map
entry arrives at the same time a map source is being added to the map
entry and a map entry re-read is also initiated at the same time an
out of order mutex locking bug which results in a hang.
---
CHANGELOG | 1 +
lib/master.c | 8 ++------
2 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/CHANGELOG b/CHANGELOG
index f215a30..5ac1648 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -67,6 +67,7 @@
- fix stale map read.
- fix null cache clean.
- automount(8) man page correction.
+- fix out of order locking in readmap.
03/09/2009 autofs-5.0.5
-----------------------
diff --git a/lib/master.c b/lib/master.c
index 4b48883..5846f72 100644
--- a/lib/master.c
+++ b/lib/master.c
@@ -624,8 +624,6 @@ struct master_mapent *master_find_mapent(struct master *master, const char *path
{
struct list_head *head, *p;
- master_mutex_lock();
-
head = &master->mounts;
list_for_each(p, head) {
struct master_mapent *entry;
@@ -638,8 +636,6 @@ struct master_mapent *master_find_mapent(struct master *master, const char *path
}
}
- master_mutex_unlock();
-
return NULL;
}
@@ -716,9 +712,7 @@ struct master_mapent *master_new_mapent(struct master *master, const char *path,
void master_add_mapent(struct master *master, struct master_mapent *entry)
{
- master_mutex_lock();
list_add_tail(&entry->list, &master->mounts);
- master_mutex_unlock();
return;
}
@@ -826,6 +820,7 @@ int master_read_master(struct master *master, time_t age, int readall)
* We need to clear and re-populate the null map entry cache
* before alowing anyone else to use it.
*/
+ master_mutex_lock();
if (master->nc) {
cache_writelock(master->nc);
nc = master->nc;
@@ -844,6 +839,7 @@ int master_read_master(struct master *master, time_t age, int readall)
master_init_scan();
lookup_nss_read_master(master, age);
cache_unlock(nc);
+ master_mutex_unlock();
if (!master->read_fail)
master_mount_mounts(master, age, readall);