LU-8354 ldlm: soft lockup in ldlm_plain_compat_queue

[fs/lustre-release.git] / lustre / ldlm / ldlm_plain.c

diff --git a/lustre/ldlm/ldlm_plain.c b/lustre/ldlm/ldlm_plain.c
index 6a99608..bbc355f 100644 (file)
--- a/lustre/ldlm/ldlm_plain.c
+++ b/lustre/ldlm/ldlm_plain.c
@@ -73,14 +73,14 @@ ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                        struct list_head *work_list)
 {
        enum ldlm_mode req_mode = req->l_req_mode;
-       struct ldlm_lock *lock;
-       struct list_head *tmp;
+       struct ldlm_lock *lock, *next_lock;
        int compat = 1;
        ENTRY;
 
        lockmode_verify(req_mode);
 
-       list_for_each_entry(lock, queue, l_res_link) {
+       list_for_each_entry_safe(lock, next_lock, queue, l_res_link) {
+
                /* We stop walking the queue if we hit ourselves so we don't
                 * take conflicting locks enqueued after us into account,
                 * or we'd wait forever. */
@@ -88,8 +88,10 @@ ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                        RETURN(compat);
 
                /* Advance loop cursor to last lock of mode group. */
-               tmp = &list_entry(lock->l_sl_mode.prev, struct ldlm_lock,
-                                 l_sl_mode)->l_res_link;
+               next_lock = list_entry(list_entry(lock->l_sl_mode.prev,
+                                                 struct ldlm_lock,
+                                                 l_sl_mode)->l_res_link.next,
+                                      struct ldlm_lock, l_res_link);
 
                if (lockmode_compat(lock->l_req_mode, req_mode))
                         continue;