From 2c3047d7f6bd8cdd1d92cab32893cecdd5a1dfa9 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Fri, 22 Mar 2019 19:48:35 +0800
Subject: [PATCH] clear mpp path reference when path is freed, otherwise double
  free may occur in verify_paths.

call stack:
    vecs=vecs@entry=0x557b01d62140, rpvec=rpvec@entry=0x0) at structs_vec.c:521
    at main.c:574
    uev=<optimized out>) at main.c:510
    uev_trigger=uev_trigger@entry=0x557affdfe3d0 <uev_trigger>, trigger_data=<optimized out>)
    at uevent.c:178
---
 libmultipath/discovery.c | 10 ++++++----
 libmultipath/discovery.h |  2 +-
 multipathd/main.c        | 23 ++++++++++++++++++++++-
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 53fc67a..305d27c 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -112,7 +112,7 @@ transport (int h)
 }
 
 int
-remove_local_path (vector pathvec, struct path *pp)
+remove_local_path (vector pathvec, struct path *pp, int isfree)
 {
 	int i = -1;
 
@@ -127,7 +127,9 @@ remove_local_path (vector pathvec, struct path *pp)
 	if ((i = find_slot(pathvec, (void *)pp)) != -1) {
 		vector_del_slot(pathvec, i);
 	}
-	free_path(pp);
+	if(isfree){
+		free_path(pp);
+	}
 	return 0;
 }
 
@@ -235,7 +237,7 @@ path_discover (vector pathvec, struct config * conf,
 			if (err == 1)
 				return 1;
 			if (err == 0)
-				remove_local_path(pathvec, pp);
+				remove_local_path(pathvec, pp, 1);
 			return 0;
 		}
 	}
@@ -243,7 +245,7 @@ path_discover (vector pathvec, struct config * conf,
 	if (err)
 		return err;
 
-	remove_local_path(pathvec, pp);
+	remove_local_path(pathvec, pp, 1);
 	return err;
 }
 
diff --git a/libmultipath/discovery.h b/libmultipath/discovery.h
index c4b1d25..0fb0d3a 100644
--- a/libmultipath/discovery.h
+++ b/libmultipath/discovery.h
@@ -53,7 +53,7 @@ ssize_t sysfs_get_vpd (struct udev_device * udev, int pg, unsigned char * buff,
 int sysfs_get_asymmetric_access_state(struct path *pp,
 				      char *buff, int buflen);
 int get_uid(struct path * pp, int path_state, struct udev_device *udev);
-int remove_local_path(vector pathvec, struct path *pp);
+int remove_local_path(vector pathvec, struct path *pp, int isfree);
 
 /*
  * discovery bitmask
diff --git a/multipathd/main.c b/multipathd/main.c
index b180f2a..8de0871 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -815,6 +815,21 @@ ev_remove_map (char * devname, char * alias, int minor, struct vectors * vecs)
 	return flush_map(mpp, vecs, 0);
 }
 
+static
+void clear_ref_from_mpp(struct path * pp, struct vectors * vecs)
+{
+	struct multipath * mpp = NULL;
+	int i = -1;
+
+	mpp = find_mp_by_wwid(vecs->mpvec, pp->wwid);
+	if(!!mpp){
+		condlog(2, "%s: clear path from mpp %s", pp->dev, mpp->alias);
+		if ((i = find_slot(mpp->paths, (void *)pp)) != -1){
+			vector_del_slot(mpp->paths, i);
+		}
+	}
+}
+
 static int
 uev_add_path (struct uevent *uev, struct vectors * vecs, int need_do_map)
 {
@@ -857,6 +872,7 @@ uev_add_path (struct uevent *uev, struct vectors * vecs, int need_do_map)
 				i = find_slot(vecs->pathvec, (void *)pp);
 				if (i != -1)
 					vector_del_slot(vecs->pathvec, i);
+				clear_ref_from_mpp(pp, vecs);
 				free_path(pp);
 			} else {
 				condlog(0, "%s: failed to reinitialize path",
@@ -918,8 +934,11 @@ ev_add_path (struct path * pp, struct vectors * vecs, int need_do_map)
 	int ret;
 
 	/* if pp is local path,remove it and return 0. */
-	if (!remove_local_path(vecs->pathvec, pp))
+	if (!remove_local_path(vecs->pathvec, pp, 0)){
+		clear_ref_from_mpp(pp, vecs);
+		free_path(pp);
 		return 0;
+	}
 
 	/*
 	 * need path UID to go any further
@@ -950,6 +969,7 @@ rescan:
 			int i = find_slot(vecs->pathvec, (void *)pp);
 			if (i != -1)
 				vector_del_slot(vecs->pathvec, i);
+			clear_ref_from_mpp(pp, vecs);
 			free_path(pp);
 			return 1;
 		}
@@ -1182,6 +1202,7 @@ out:
 	if ((i = find_slot(vecs->pathvec, (void *)pp)) != -1)
 		vector_del_slot(vecs->pathvec, i);
 
+	clear_ref_from_mpp(pp, vecs);
 	free_path(pp);
 
 	return retval;
-- 
2.19.1