[PATCH 1/1] io_uring: clean rings on NO_MMAP alloc fail

[PATCH 1/1] io_uring: clean rings on NO_MMAP alloc fail

[Pavel Begunkov]

We make a few cancellation judgements based on ctx->rings, so let's
zero it afer deallocation for IORING_SETUP_NO_MMAP just like it's
done with the mmap case. Likely, it's not a real problem, but zeroing
is safer and better tested.

Cc: stable@vger.kernel.org
Fixes: 03d89a2de25bbc ("io_uring: support for user allocated memory for rings/sqes")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/io_uring.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 49a124daa359..e7d7a456b489 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2788,14 +2788,15 @@ static void io_rings_free(struct io_ring_ctx *ctx)
 	if (!(ctx->flags & IORING_SETUP_NO_MMAP)) {
 		io_mem_free(ctx->rings);
 		io_mem_free(ctx->sq_sqes);
-		ctx->rings = NULL;
-		ctx->sq_sqes = NULL;
 	} else {
 		io_pages_free(&ctx->ring_pages, ctx->n_ring_pages);
 		ctx->n_ring_pages = 0;
 		io_pages_free(&ctx->sqe_pages, ctx->n_sqe_pages);
 		ctx->n_sqe_pages = 0;
 	}
+
+	ctx->rings = NULL;
+	ctx->sq_sqes = NULL;
 }
 
 void *io_mem_alloc(size_t size)
-- 
2.43.0

Re: [PATCH 1/1] io_uring: clean rings on NO_MMAP alloc fail

[Jens Axboe]

On Tue, 12 Mar 2024 14:56:27 +0000, Pavel Begunkov wrote:
> We make a few cancellation judgements based on ctx->rings, so let's
> zero it afer deallocation for IORING_SETUP_NO_MMAP just like it's
> done with the mmap case. Likely, it's not a real problem, but zeroing
> is safer and better tested.
> 
> 

Applied, thanks!

[1/1] io_uring: clean rings on NO_MMAP alloc fail
      commit: cef59d1ea7170ec753182302645a0191c8aa3382

Best regards,
-- 
Jens Axboe