NFSv4: Fix an oopsable condition in nfs_free_seqid
Storing a pointer to the struct rpc_task in the nfs_seqid is broken
since the nfs_seqid may be freed well after the task has been destroyed.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 23834c8..da0861d 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -676,7 +676,6 @@
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (new != NULL) {
new->sequence = counter;
- new->task = NULL;
spin_lock(&sequence->lock);
list_add_tail(&new->list, &sequence->list);
spin_unlock(&sequence->lock);
@@ -687,15 +686,10 @@
void nfs_free_seqid(struct nfs_seqid *seqid)
{
struct rpc_sequence *sequence = seqid->sequence->sequence;
- struct rpc_task *next = NULL;
spin_lock(&sequence->lock);
list_del(&seqid->list);
- if (!list_empty(&sequence->list)) {
- next = list_entry(sequence->list.next, struct nfs_seqid, list)->task;
- if (next)
- rpc_wake_up_task(next);
- }
+ rpc_wake_up(&sequence->wait);
spin_unlock(&sequence->lock);
kfree(seqid);
}
@@ -754,7 +748,6 @@
spin_lock(&sequence->lock);
if (sequence->list.next != &seqid->list) {
- seqid->task = task;
rpc_sleep_on(&sequence->wait, task, NULL, NULL);
status = -EAGAIN;
}