[dm-devel] [PATCH] multipathd: fix uev_update_path dead lock
tang.wenjun3 at zte.com.cn
tang.wenjun3 at zte.com.cn
Tue Nov 8 03:05:01 UTC 2016
From: 10144149 <tang.wenjun3 at zte.com.cn>
Deadlock occurred in uev_add_path() when &vecs->lock would lock twice in uev_update_path()
---
multipathd/main.c | 54 ++++++++++++++++++++++++++++++------------------------
multipathd/main.h | 1 +
2 files changed, 31 insertions(+), 24 deletions(-)
diff --git a/multipathd/main.c b/multipathd/main.c
index d6f081f..e74d124 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -611,7 +611,7 @@ static int
uev_add_path (struct uevent *uev, struct vectors * vecs)
{
struct path *pp;
- int ret = 0, i;
+ int ret = 0;
struct config *conf;
condlog(2, "%s: add path (uevent)", uev->kernel);
@@ -628,32 +628,11 @@ uev_add_path (struct uevent *uev, struct vectors * vecs)
pthread_testcancel();
pp = find_path_by_dev(vecs->pathvec, uev->kernel);
if (pp) {
- int r;
-
condlog(0, "%s: spurious uevent, path already in pathvec",
uev->kernel);
if (!pp->mpp && !strlen(pp->wwid)) {
condlog(3, "%s: reinitialize path", uev->kernel);
- udev_device_unref(pp->udev);
- pp->udev = udev_device_ref(uev->udev);
- conf = get_multipath_config();
- r = pathinfo(pp, conf,
- DI_ALL | DI_BLACKLIST);
- put_multipath_config(conf);
- if (r == PATHINFO_OK)
- ret = ev_add_path(pp, vecs);
- else if (r == PATHINFO_SKIPPED) {
- condlog(3, "%s: remove blacklisted path",
- uev->kernel);
- i = find_slot(vecs->pathvec, (void *)pp);
- if (i != -1)
- vector_del_slot(vecs->pathvec, i);
- free_path(pp);
- } else {
- condlog(0, "%s: failed to reinitialize path",
- uev->kernel);
- ret = 1;
- }
+ ret = ev_add_path_with_pathinfo(uev->udev, pp, vecs);
}
}
lock_cleanup_pop(vecs->lock);
@@ -693,6 +672,33 @@ uev_add_path (struct uevent *uev, struct vectors * vecs)
return ret;
}
+int
+ev_add_path_with_pathinfo (struct udev_device *udevice, struct path * pp, struct vectors * vecs)
+{
+ int r;
+ int ret = 0, i;
+ struct config *conf;
+
+ udev_device_unref(pp->udev);
+ pp->udev = udev_device_ref(udevice);
+ conf = get_multipath_config();
+ r = pathinfo(pp, conf, DI_ALL | DI_BLACKLIST);
+ put_multipath_config(conf);
+ if (r == PATHINFO_OK)
+ ret = ev_add_path(pp, vecs);
+ else if (r == PATHINFO_SKIPPED) {
+ condlog(3, "%s: remove blacklisted path", pp->dev);
+ i = find_slot(vecs->pathvec, (void *)pp);
+ if (i != -1)
+ vector_del_slot(vecs->pathvec, i);
+ free_path(pp);
+ } else {
+ condlog(0, "%s: failed to reinitialize path", pp->dev);
+ ret = 1;
+ }
+ return ret;
+}
+
/*
* returns:
* 0: added
@@ -995,7 +1001,7 @@ uev_update_path (struct uevent *uev, struct vectors * vecs)
}
if (pp->initialized == INIT_REQUESTED_UDEV)
- retval = uev_add_path(uev, vecs);
+ retval = ev_add_path_with_pathinfo(uev->udev, pp, vecs);
else if (mpp && ro >= 0) {
condlog(2, "%s: update path write_protect to '%d' (uevent)", uev->kernel, ro);
diff --git a/multipathd/main.h b/multipathd/main.h
index f72580d..d3cd145 100644
--- a/multipathd/main.h
+++ b/multipathd/main.h
@@ -23,6 +23,7 @@ const char * daemon_status(void);
int need_to_delay_reconfig (struct vectors *);
int reconfigure (struct vectors *);
int ev_add_path (struct path *, struct vectors *);
+int ev_add_path_with_pathinfo (struct udev_device *, struct path *, struct vectors *);
int ev_remove_path (struct path *, struct vectors *);
int ev_add_map (char *, char *, struct vectors *);
int ev_remove_map (char *, char *, int, struct vectors *);
--
2.8.1.windows.1
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