[PATCH 5.12] io_uring: fix unrelated ctx reqs cancellation

[PATCH 5.12] io_uring: fix unrelated ctx reqs cancellation

[Pavel Begunkov]

io-wq now is per-task, so cancellations now should match against
request's ctx.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---

p.s. have a test for it, but will in a bundle after another problem gets
solved.

 fs/io_uring.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9a7cb641210a..5c6a54520be0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5574,22 +5574,30 @@ static int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
 	return 0;
 }
 
+struct io_cancel_data {
+	struct io_ring_ctx *ctx;
+	u64 user_data;
+};
+
 static bool io_cancel_cb(struct io_wq_work *work, void *data)
 {
 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+	struct io_cancel_data *cd = data;
 
-	return req->user_data == (unsigned long) data;
+	return req->ctx == cd->ctx && req->user_data == cd->user_data;
 }
 
-static int io_async_cancel_one(struct io_uring_task *tctx, void *sqe_addr)
+static int io_async_cancel_one(struct io_uring_task *tctx, u64 user_data,
+			       struct io_ring_ctx *ctx)
 {
+	struct io_cancel_data data = { .ctx = ctx, .user_data = user_data, };
 	enum io_wq_cancel cancel_ret;
 	int ret = 0;
 
-	if (!tctx->io_wq)
+	if (!tctx || !tctx->io_wq)
 		return -ENOENT;
 
-	cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, sqe_addr, false);
+	cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, &data, false);
 	switch (cancel_ret) {
 	case IO_WQ_CANCEL_OK:
 		ret = 0;
@@ -5612,8 +5620,7 @@ static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
 	unsigned long flags;
 	int ret;
 
-	ret = io_async_cancel_one(req->task->io_uring,
-					(void *) (unsigned long) sqe_addr);
+	ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
 	if (ret != -ENOENT) {
 		spin_lock_irqsave(&ctx->completion_lock, flags);
 		goto done;
-- 
2.24.0

Re: [PATCH 5.12] io_uring: fix unrelated ctx reqs cancellation

[Jens Axboe]

On 3/8/21 5:14 AM, Pavel Begunkov wrote:
> io-wq now is per-task, so cancellations now should match against
> request's ctx.

Applied, thanks.

-- 
Jens Axboe