Fix racy assignment of zcb.zcb_haderrors

zcb_haderrors will be modified in zdb_blkptr_done, which is asynchronous. So we must move this assignment after zio_wait. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: loli10K <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Closes #7099
openzfs · Mar 14, 2018 · c797f08 · c797f08
1 parent 5e566c5
commit c797f08
Showing 1 changed file with 8 additions and 2 deletions.
diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
@@ -3313,7 +3313,7 @@ dump_block_stats(spa_t *spa)
 	uint64_t norm_alloc, norm_space, total_alloc, total_found;
 	int flags = TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_HARD;
 	boolean_t leaks = B_FALSE;
-	int e, c;
+	int e, c, err;
 	bp_embedded_type_t i;
 
 	(void) printf("\nTraversing all blocks %s%s%s%s%s...\n\n",
@@ -3354,7 +3354,7 @@ dump_block_stats(spa_t *spa)
 
 	zcb.zcb_totalasize = metaslab_class_get_alloc(spa_normal_class(spa));
 	zcb.zcb_start = zcb.zcb_lastprint = gethrtime();
-	zcb.zcb_haderrors |= traverse_pool(spa, 0, flags, zdb_blkptr_cb, &zcb);
+	err = traverse_pool(spa, 0, flags, zdb_blkptr_cb, &zcb);
 
 	/*
 	 * If we've traversed the data blocks then we need to wait for those
@@ -3370,6 +3370,12 @@ dump_block_stats(spa_t *spa)
 		}
 	}
 
+	/*
+	 * Done after zio_wait() since zcb_haderrors is modified in
+	 * zdb_blkptr_done()
+	 */
+	zcb.zcb_haderrors |= err;
+
 	if (zcb.zcb_haderrors) {
 		(void) printf("\nError counts:\n\n");
 		(void) printf("\t%5s  %s\n", "errno", "count");