autofs-5.1.9 - fix deadlock in remount From: Ian Kent 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 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 --- CHANGELOG | 1 + modules/parse_sun.c | 26 ++++++++++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) --- autofs-5.1.7.orig/CHANGELOG +++ autofs-5.1.7/CHANGELOG @@ -160,6 +160,7 @@ - allow -null map in indirect maps. - fix multi-mount check. - fix get parent multi-mount check in try_remount(). +- fix deadlock in remount. 25/01/2021 autofs-5.1.7 - make bind mounts propagation slave by default. --- autofs-5.1.7.orig/modules/parse_sun.c +++ autofs-5.1.7/modules/parse_sun.c @@ -889,7 +889,18 @@ 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); @@ -1581,7 +1592,18 @@ 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);