From: Bixuan Cui cuibixuan@huawei.com
[ Upstream commit 71e1cef2d794338cc7b979d4c6144e1dc12718b5 ]
While task_work_add() in io_workqueue_create() is true, then duplicate code is executed:
-> clear_bit_unlock(0, &worker->create_state); -> io_worker_release(worker); -> atomic_dec(&acct->nr_running); -> io_worker_ref_put(wq); -> return false;
-> clear_bit_unlock(0, &worker->create_state); // back to io_workqueue_create() -> io_worker_release(worker); -> kfree(worker);
The io_worker_release() and clear_bit_unlock() are executed twice.
Fixes: 3146cba99aa2 ("io-wq: make worker creation resilient against signals") Signed-off-by: Bixuan Cui cuibixuan@huawei.com Link: https://lore.kernel.org/r/20210911085847.34849-1-cuibixuan@huawei.com Reviwed-by: Hao Xu haoxu@linux.alibaba.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- fs/io-wq.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c index 203c0e2a5dfae..5d189b24a8d4b 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -359,8 +359,10 @@ static bool io_queue_worker_create(struct io_worker *worker,
init_task_work(&worker->create_work, func); worker->create_index = acct->index; - if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) + if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) { + clear_bit_unlock(0, &worker->create_state); return true; + } clear_bit_unlock(0, &worker->create_state); fail_release: io_worker_release(worker); @@ -765,11 +767,8 @@ static void io_workqueue_create(struct work_struct *work) struct io_worker *worker = container_of(work, struct io_worker, work); struct io_wqe_acct *acct = io_wqe_get_acct(worker);
- if (!io_queue_worker_create(worker, acct, create_worker_cont)) { - clear_bit_unlock(0, &worker->create_state); - io_worker_release(worker); + if (!io_queue_worker_create(worker, acct, create_worker_cont)) kfree(worker); - } }
static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)