From ebb351cf78ee6bf3262e6b4b6906f456c05e6d5e Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Tue, 4 Dec 2012 15:21:53 +0100 Subject: llist/xen-blkfront: implement safe version of llist_for_each_entry MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Implement a safe version of llist_for_each_entry, and use it in blkif_free. Previously grants where freed while iterating the list, which lead to dereferences when trying to fetch the next item. Reported-by: Dan Carpenter Signed-off-by: Roger Pau Monné Acked-by: Andrew Morton [v2: Move the llist_for_each_entry_safe in llist.h] Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkfront.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 96e9b00..cfdb033 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -792,6 +792,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) { struct llist_node *all_gnts; struct grant *persistent_gnt; + struct llist_node *n; /* Prevent new requests being issued until we fix things up. */ spin_lock_irq(&info->io_lock); @@ -804,7 +805,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) /* Remove all persistent grants */ if (info->persistent_gnts_c) { all_gnts = llist_del_all(&info->persistent_gnts); - llist_for_each_entry(persistent_gnt, all_gnts, node) { + llist_for_each_entry_safe(persistent_gnt, n, all_gnts, node) { gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); __free_page(pfn_to_page(persistent_gnt->pfn)); kfree(persistent_gnt); -- cgit v1.1