On 3/16/24 16:14, Jens Axboe wrote:
On 3/15/24 5:28 PM, Pavel Begunkov wrote:
On 3/15/24 23:25, Jens Axboe wrote:
On 3/15/24 5:19 PM, Pavel Begunkov wrote:
On 3/15/24 23:13, Pavel Begunkov wrote:
On 3/15/24 23:09, Pavel Begunkov wrote:
On 3/15/24 22:48, Jens Axboe wrote:
If we get a request with IOSQE_ASYNC set, then we first run the prep
async handlers. But if we then fail setting it up and want to post
a CQE with -EINVAL, we use ->done_io. This was previously guarded with
REQ_F_PARTIAL_IO, and the normal setup handlers do set it up before any
potential errors, but we need to cover the async setup too.
You can hit io_req_defer_failed() { opdef->fail(); }
off of an early submission failure path where def->prep has
not yet been called, I don't think the patch will fix the
problem.
->fail() handlers are fragile, maybe we should skip them
if def->prep() wasn't called. Not even compile tested:
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 846d67a9c72e..56eed1490571 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
[...]
def->fail(req);
io_req_complete_defer(req);
}
@@ -2201,8 +2201,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
}
req->flags |= REQ_F_CREDS;
}
-
- return def->prep(req, sqe);
+ return 0;
}
static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
@@ -2250,8 +2249,15 @@ static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
int ret;
ret = io_init_req(ctx, req, sqe);
- if (unlikely(ret))
+ if (unlikely(ret)) {
+fail:
Obvious the diff is crap, but still bugging me enough to write
that the label should've been one line below, otherwise we'd
flag after ->prep as well.
It certainly needs testing :-)
We can go either way - patch up the net thing, or do a proper EARLY_FAIL
and hopefully not have to worry about it again. Do you want to clean it
up, test it, and send it out?
I'd rather leave it to you, I suspect it wouldn't fix the syzbot
report w/o fiddling with done_io as in your patch.
I gave this a shot, but some fail handlers do want to get called. But
Which one and/or which part of it?
they can't use sr->done_io at that point. I'll ponder this a bit and see
what the best generic solution is.
--
Pavel Begunkov
