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authorLinus Torvalds <torvalds@linux-foundation.org>2021-05-28 14:35:55 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-28 14:35:55 -1000
commitb3dbbae60993365ab4a7ba3f9f6f6eca722b57c1 (patch)
tree3fc814ae9657a55988dbd2fb79a9890a222b4a82 /fs
parent567d1fd853b8786f93ba399c8ff7c8106bed5fe5 (diff)
parentb16ef427adf31fb4f6522458d37b3fe21d6d03b8 (diff)
Merge tag 'io_uring-5.13-2021-05-28' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe: "A few minor fixes: - Fix an issue with hashed wait removal on exit (Zqiang, Pavel) - Fix a recent data race introduced in this series (Marco)" * tag 'io_uring-5.13-2021-05-28' of git://git.kernel.dk/linux-block: io_uring: fix data race to avoid potential NULL-deref io-wq: Fix UAF when wakeup wqe in hash waitqueue io_uring/io-wq: close io-wq full-stop gap
Diffstat (limited to 'fs')
-rw-r--r--fs/io-wq.c29
-rw-r--r--fs/io-wq.h2
-rw-r--r--fs/io_uring.c15
3 files changed, 29 insertions, 17 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 5361a9b4b47b..b3e8624a37d0 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -979,13 +979,16 @@ static bool io_task_work_match(struct callback_head *cb, void *data)
return cwd->wqe->wq == data;
}
+void io_wq_exit_start(struct io_wq *wq)
+{
+ set_bit(IO_WQ_BIT_EXIT, &wq->state);
+}
+
static void io_wq_exit_workers(struct io_wq *wq)
{
struct callback_head *cb;
int node;
- set_bit(IO_WQ_BIT_EXIT, &wq->state);
-
if (!wq->task)
return;
@@ -1003,13 +1006,16 @@ static void io_wq_exit_workers(struct io_wq *wq)
struct io_wqe *wqe = wq->wqes[node];
io_wq_for_each_worker(wqe, io_wq_worker_wake, NULL);
- spin_lock_irq(&wq->hash->wait.lock);
- list_del_init(&wq->wqes[node]->wait.entry);
- spin_unlock_irq(&wq->hash->wait.lock);
}
rcu_read_unlock();
io_worker_ref_put(wq);
wait_for_completion(&wq->worker_done);
+
+ for_each_node(node) {
+ spin_lock_irq(&wq->hash->wait.lock);
+ list_del_init(&wq->wqes[node]->wait.entry);
+ spin_unlock_irq(&wq->hash->wait.lock);
+ }
put_task_struct(wq->task);
wq->task = NULL;
}
@@ -1020,8 +1026,6 @@ static void io_wq_destroy(struct io_wq *wq)
cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
- io_wq_exit_workers(wq);
-
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
struct io_cb_cancel_data match = {
@@ -1036,16 +1040,13 @@ static void io_wq_destroy(struct io_wq *wq)
kfree(wq);
}
-void io_wq_put(struct io_wq *wq)
-{
- if (refcount_dec_and_test(&wq->refs))
- io_wq_destroy(wq);
-}
-
void io_wq_put_and_exit(struct io_wq *wq)
{
+ WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state));
+
io_wq_exit_workers(wq);
- io_wq_put(wq);
+ if (refcount_dec_and_test(&wq->refs))
+ io_wq_destroy(wq);
}
static bool io_wq_worker_affinity(struct io_worker *worker, void *data)
diff --git a/fs/io-wq.h b/fs/io-wq.h
index 0e6d310999e8..af2df0680ee2 100644
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -122,7 +122,7 @@ struct io_wq_data {
};
struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data);
-void io_wq_put(struct io_wq *wq);
+void io_wq_exit_start(struct io_wq *wq);
void io_wq_put_and_exit(struct io_wq *wq);
void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5f82954004f6..903458afd56c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -9039,11 +9039,16 @@ static void io_uring_clean_tctx(struct io_uring_task *tctx)
struct io_tctx_node *node;
unsigned long index;
- tctx->io_wq = NULL;
xa_for_each(&tctx->xa, index, node)
io_uring_del_task_file(index);
- if (wq)
+ if (wq) {
+ /*
+ * Must be after io_uring_del_task_file() (removes nodes under
+ * uring_lock) to avoid race with io_uring_try_cancel_iowq().
+ */
+ tctx->io_wq = NULL;
io_wq_put_and_exit(wq);
+ }
}
static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
@@ -9078,6 +9083,9 @@ static void io_uring_cancel_sqpoll(struct io_sq_data *sqd)
if (!current->io_uring)
return;
+ if (tctx->io_wq)
+ io_wq_exit_start(tctx->io_wq);
+
WARN_ON_ONCE(!sqd || sqd->thread != current);
atomic_inc(&tctx->in_idle);
@@ -9112,6 +9120,9 @@ void __io_uring_cancel(struct files_struct *files)
DEFINE_WAIT(wait);
s64 inflight;
+ if (tctx->io_wq)
+ io_wq_exit_start(tctx->io_wq);
+
/* make sure overflow events are dropped */
atomic_inc(&tctx->in_idle);
do {

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