Commit 7f709a48 authored by Trond Myklebust's avatar Trond Myklebust

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: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent cb1f7be7
......@@ -112,7 +112,6 @@ struct nfs_seqid_counter {
struct nfs_seqid {
struct list_head list;
struct nfs_seqid_counter *sequence;
struct rpc_task *task;
};
static inline void nfs_confirm_seqid(struct nfs_seqid_counter *seqid, int status)
......
......@@ -676,7 +676,6 @@ struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter)
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 @@ struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter)
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 @@ int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task)
spin_lock(&sequence->lock);
if (sequence->list.next != &seqid->list) {
seqid->task = task;
rpc_sleep_on(&sequence->wait, task, NULL, NULL);
status = -EAGAIN;
}
......
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