io_uring/cmd: let cmds to know about dying task

When the taks that submitted a request is dying, a task work for that
request might get run by a kernel thread or even worse by a half
dismantled task. We can't just cancel the task work without running the
callback as the cmd might need to do some clean up, so pass a flag
instead. If set, it's not safe to access any task resources and the
callback is expected to cancel the cmd ASAP.

Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Pavel Begunkov 2024-11-04 16:12:04 +00:00 committed by David Sterba
parent 1cc86aeada
commit df3b8ca604
2 changed files with 6 additions and 1 deletions

View File

@ -37,6 +37,7 @@ enum io_uring_cmd_flags {
/* set when uring wants to cancel a previously issued command */
IO_URING_F_CANCEL = (1 << 11),
IO_URING_F_COMPAT = (1 << 12),
IO_URING_F_TASK_DEAD = (1 << 13),
};
struct io_wq_work_node {

View File

@ -119,9 +119,13 @@ EXPORT_SYMBOL_GPL(io_uring_cmd_mark_cancelable);
static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
unsigned int flags = IO_URING_F_COMPLETE_DEFER;
if (current->flags & (PF_EXITING | PF_KTHREAD))
flags |= IO_URING_F_TASK_DEAD;
/* task_work executor checks the deffered list completion */
ioucmd->task_work_cb(ioucmd, IO_URING_F_COMPLETE_DEFER);
ioucmd->task_work_cb(ioucmd, flags);
}
void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,