blkdebug: Use QLIST_FOREACH_SAFE to resume IO

Qemu-iotest 030 was broken.

When the coroutine runs and finishes, it will remove itself from the req
list, so let's use safe version of foreach to avoid use after free.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/block/blkdebug.c b/block/blkdebug.c
index 37cf028545ec40bcadb7979b0bad2b51b1e2776e..957be2c76bfd03f68b6e54bc17d8daff0f646893 100644 (file)
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -594,9 +594,9 @@ static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,
 static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
 {
     BDRVBlkdebugState *s = bs->opaque;
-    BlkdebugSuspendedReq *r;
+    BlkdebugSuspendedReq *r, *next;
 
-    QLIST_FOREACH(r, &s->suspended_reqs, next) {
+    QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, next) {
         if (!strcmp(r->tag, tag)) {
             qemu_coroutine_enter(r->co, NULL);
             return 0;
@@ -609,7 +609,7 @@ static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
                                             const char *tag)
 {
     BDRVBlkdebugState *s = bs->opaque;
-    BlkdebugSuspendedReq *r;
+    BlkdebugSuspendedReq *r, *r_next;
     BlkdebugRule *rule, *next;
     int i, ret = -ENOENT;
 
@@ -622,7 +622,7 @@ static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
             }
         }
     }
-    QLIST_FOREACH(r, &s->suspended_reqs, next) {
+    QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, r_next) {
         if (!strcmp(r->tag, tag)) {
             qemu_coroutine_enter(r->co, NULL);
             ret = 0;