io_uring/msg_ring: reuse ctx->submitter_task read using READ_ONCE instead of re-readi...

In io_msg_exec_remote(), ctx->submitter_task is read using READ_ONCE at
the beginning of the function, checked, and then re-read from
ctx->submitter_task, voiding all guarantees of the checks. Reuse the value
that was read by READ_ONCE to ensure the consistency of the task struct
throughout the function.

Signed-off-by: linke li <lilinke99@qq.com>
Link: https://lore.kernel.org/r/tencent_F9B2296C93928D6F68FF0C95C33475C68209@qq.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c
index cd6dcf634ba3cdea8f97bd94a6aac7f96550fb85..d74670b39ed6dca79cebec698863db761ad37cc6 100644 (file)
--- a/io_uring/msg_ring.c
+++ b/io_uring/msg_ring.c
@@ -83,7 +83,7 @@ static int io_msg_exec_remote(struct io_kiocb *req, task_work_func_t func)
                return -EOWNERDEAD;
 
        init_task_work(&msg->tw, func);
-       if (task_work_add(ctx->submitter_task, &msg->tw, TWA_SIGNAL))
+       if (task_work_add(task, &msg->tw, TWA_SIGNAL))
                return -EOWNERDEAD;
 
        return IOU_ISSUE_SKIP_COMPLETE;