autofs/SOURCES/autofs-5.1.9-fix-deadlock-in-remount.patch

69 lines
2.3 KiB
Diff

autofs-5.1.9 - fix deadlock in remount
From: Ian Kent <raven@themaw.net>
If we're starting up or trying to re-connect to an existing direct mount
we could be iterating through the map entries with the cache readlock
held so we can't just take the writelock for direct mounts. But when
trying to re-connect to an existing mount at startup there won't be any
other process updating the map entry cache.
Signed-off-by: Ian Kent <raven@themaw.net>
---
CHANGELOG | 1 +
modules/parse_sun.c | 26 ++++++++++++++++++++++++--
2 files changed, 25 insertions(+), 2 deletions(-)
--- autofs-5.1.4.orig/CHANGELOG
+++ autofs-5.1.4/CHANGELOG
@@ -153,6 +153,7 @@
- allow -null map in indirect maps.
- fix multi-mount check.
- fix get parent multi-mount check in try_remount().
+- fix deadlock in remount.
xx/xx/2018 autofs-5.1.5
- fix flag file permission.
--- autofs-5.1.4.orig/modules/parse_sun.c
+++ autofs-5.1.4/modules/parse_sun.c
@@ -888,7 +888,18 @@ update_offset_entry(struct autofs_point
strcpy(m_mapent, loc);
}
- cache_writelock(mc);
+ /*
+ * If we're starting up or trying to re-connect to an existing
+ * direct mount we could be iterating through the map entries
+ * with the readlock held so we can't just take the writelock
+ * for direct mounts. But at when trying to re-connect to an
+ * existing mount at startup there won't be any other process
+ * updating the map entry cache.
+ */
+ if (ap->state == ST_INIT && ap->flags & MOUNT_FLAG_REMOUNT)
+ cache_readlock(mc);
+ else
+ cache_writelock(mc);
ret = cache_update_offset(mc, name, m_key, m_mapent, age);
me = cache_lookup_distinct(mc, m_key);
@@ -1580,7 +1591,18 @@ dont_expand:
free(myoptions);
} while (*p == '/' || (*p == '"' && *(p + 1) == '/'));
- cache_writelock(mc);
+ /*
+ * If we're starting up or trying to re-connect to an existing
+ * direct mount we could be iterating through the map entries
+ * with the readlock held so we can't just take the writelock
+ * for direct mounts. But at when trying to re-connect to an
+ * existing mount at startup there won't be any other process
+ * updating the map entry cache.
+ */
+ if (ap->state == ST_INIT && ap->flags & MOUNT_FLAG_REMOUNT)
+ cache_readlock(mc);
+ else
+ cache_writelock(mc);
me = cache_lookup_distinct(mc, name);
if (!me) {
cache_unlock(mc);