1 files changed, 17 insertions, 0 deletions

diff --git a/fs/aio.c b/fs/aio.c
index b4dd668fbccc..26869cde3953 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1642,6 +1642,23 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                 goto out_put_req;
 
         spin_lock_irq(&ctx->ctx_lock);
+        /*
+         * We could have raced with io_destroy() and are currently holding a
+         * reference to ctx which should be destroyed. We cannot submit IO
+         * since ctx gets freed as soon as io_submit() puts its reference.  The
+         * check here is reliable: io_destroy() sets ctx->dead before waiting
+         * for outstanding IO and the barrier between these two is realized by
+         * unlock of mm->ioctx_lock and lock of ctx->ctx_lock.  Analogously we
+         * increment ctx->reqs_active before checking for ctx->dead and the
+         * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
+         * don't see ctx->dead set here, io_destroy() waits for our IO to
+         * finish.
+         */
+        if (ctx->dead) {
+                spin_unlock_irq(&ctx->ctx_lock);
+                ret = -EINVAL;
+                goto out_put_req;
+        }
         aio_run_iocb(req);
         if (!list_empty(&ctx->run_list)) {
                 /* drain the run list */