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Subject[PATCH] fs/ubifs/orphan.c: remove invalid reference to list iterator variable
Date
From: Julia Lawall <Julia.Lawall@lip6.fr>

If list_for_each_entry, etc complete a traversal of the list, the iterator
variable ends up pointing to an address at an offset from the list head,
and not a meaningful structure. Thus this value should not be used after
the end of the iterator. Replace a field access from orphan by NULL in two
places.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier c;
expression E;
iterator name list_for_each_entry;
statement S;
@@

list_for_each_entry(c,...) { ... when != break;
when forall
when strict
}
...
(
c = E
*c
)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
fs/ubifs/orphan.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index b02734d..cebf17e 100644
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -176,7 +176,7 @@ int ubifs_orphan_start_commit(struct ubifs_info *c)
*last = orphan;
last = &orphan->cnext;
}
- *last = orphan->cnext;
+ *last = NULL;
c->cmt_orphans = c->new_orphans;
c->new_orphans = 0;
dbg_cmt("%d orphans to commit", c->cmt_orphans);
@@ -382,7 +382,7 @@ static int consolidate(struct ubifs_info *c)
last = &orphan->cnext;
cnt += 1;
}
- *last = orphan->cnext;
+ *last = NULL;
ubifs_assert(cnt == c->tot_orphans - c->new_orphans);
c->cmt_orphans = cnt;
c->ohead_lnum = c->orph_first;


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