From: Artem Bityutskiy Date: Sun, 8 Aug 2010 09:45:23 +0000 (+0300) Subject: UBIFS: fix assertion warnings in comparison function X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=1a9476a77083354005750c9df45ba9d71ad12c8c;p=openwrt%2Fstaging%2Fblogic.git UBIFS: fix assertion warnings in comparison function When running the integrity test ('integck' from mtd-utils) on current UBIFS on 2.6.35, I see that assertions in UBIFS 'list_sort()' comparison functions trigger sometimes, e.g.: UBIFS assert failed in data_nodes_cmp at 132 (pid 28311) My investigation showed that this happens when 'list_sort()' calls the 'cmp()' function with equivalent arguments. In this case, the 'struct list_head' parameter, passed to 'cmp()' is bogus, and it does not belong to any element in the original list. And this issue seems to be introduced by commit: commit 835cc0c8477fdbc59e0217891d6f11061b1ac4e2 Author: Don Mullis Date: Fri Mar 5 13:43:15 2010 -0800 It is easy to work around the issue by doing: if (a == b) return 0; in UBIFS. It works, but 'lib_sort()' should nevertheless be fixed. Although it is harmless to have this piece of code in UBIFS. This patch adds that code to both UBIFS 'cmp()' functions: 'data_nodes_cmp()' and 'nondata_nodes_cmp()'. Signed-off-by: Artem Bityutskiy --- diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c index dafef3d195d3..4fc31ca0e3b1 100644 --- a/fs/ubifs/gc.c +++ b/fs/ubifs/gc.c @@ -125,6 +125,9 @@ int data_nodes_cmp(void *priv, struct list_head *a, struct list_head *b) struct ubifs_scan_node *sa, *sb; cond_resched(); + if (a == b) + return 0; + sa = list_entry(a, struct ubifs_scan_node, list); sb = list_entry(b, struct ubifs_scan_node, list); @@ -165,6 +168,9 @@ int nondata_nodes_cmp(void *priv, struct list_head *a, struct list_head *b) struct ubifs_scan_node *sa, *sb; cond_resched(); + if (a == b) + return 0; + sa = list_entry(a, struct ubifs_scan_node, list); sb = list_entry(b, struct ubifs_scan_node, list);