When one iscsi device logs in and logs out with the "multipath -r" executed at the same time, memory leak happens in multipathd process.
The reason is following. When "multipath -r" is executed, the path will be free in configure function. Before path_discovery executed, iscsi device logs out. Then path_discovery will not find any path and there is no path in the gvecs->pathvec. When map_discovery function is executed, disassemble_map function will be called. Because gvecs->pathvec->slot is empty and is_deamon is 1, a path will be allocated and is not stored in gvecs->pathvec but store in mpp->pg. But when the mpp is removed and freed by remove_map function, the path will not be free and can't be find anymore.
The procedure details given as follows, 1."multipath -r" is executed main ->child ->reconfigure ->configure ->path_discovery //after iscsi logout ->map_discovery ->update_multipath_table ->disassemble_map ->alloc_path 2.then "multipath -r" is executed again main ->child ->reconfigure ->remove_maps_and_stop_waiters ->remove_maps
Here, we skip alloc_path if pp isn't find in pathvec and process is daemon. In daemon, we should not store path with incomplete information to pathvec. The pathvec stores all paths in daemon, so it is reasonable keep same with pathvec.
Reported-by: Tianxiong Lu lutianxiong@huawei.com Signed-off-by: Lixiaokeng lixiaokeng@huawei.com Signed-off-by: Zhiqiang Liu liuzhiqiang26@huawei.com --- libmultipath/dmparser.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/libmultipath/dmparser.c b/libmultipath/dmparser.c index 7da5fbf..3ce6eb3 100644 --- a/libmultipath/dmparser.c +++ b/libmultipath/dmparser.c @@ -305,6 +305,16 @@ int disassemble_map(vector pathvec, char *params, struct multipath *mpp, }
if (!pp) { + /* daemon should keep same with pathvec */ + /* pp is not find in pathvec, skip it */ + if (is_daemon) { + FREE(word); + for (k = 0; k < num_paths_args; k++) { + p += get_word(p, NULL); + } + continue; + } + pp_unfound = 1; pp = alloc_path();
@@ -317,8 +327,7 @@ int disassemble_map(vector pathvec, char *params, struct multipath *mpp, strlcpy(pp->wwid, mpp->wwid, WWID_SIZE); } - /* Only call this in multipath client mode */ - if (!is_daemon && store_path(pathvec, pp)) { + if (store_path(pathvec, pp)) { free_path(pp); goto out1; } --