From: Jens Axboe <axboe@xxxxxxxxx>
commit e6db6f9398dadcbc06318a133d4c44a2d3844e61 upstream.
We have two types of task_work based creation, one is using an existing
worker to setup a new one (eg when going to sleep and we have no free
workers), and the other is allocating a new worker. Only the latter
should be freed when we cancel task_work creation for a new worker.
Fixes: af82425c6a2d ("io_uring/io-wq: free worker if task_work creation is canceled")
Reported-by: syzbot+d56ec896af3637bdb7e4@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/io-wq.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
@@ -1217,7 +1217,12 @@ static void io_wq_cancel_tw_create(struc
worker = container_of(cb, struct io_worker, create_work);
io_worker_cancel_cb(worker);
- kfree(worker);
+ /*
+ * Only the worker continuation helper has worker allocated and
+ * hence needs freeing.
+ */
+ if (cb->func == create_worker_cont)
+ kfree(worker);
}
}
