From 9865346b7e8374b57f1c3ccacdc77846c6352ff4 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 5 Dec 2023 07:02:13 -0700
Subject: [PATCH] io_uring/kbuf: check for buffer list readiness after NULL
check
Move the buffer list 'is_ready' check below the validity check for
the buffer list for a given group.
Fixes: 5cf4f52e6d8a ("io_uring: free io_buffer_list entries via RCU")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
io_uring/kbuf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index bd25bc2deeaf8..72b6af1d2ed3b 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -756,6 +756,8 @@ void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
bl = __io_buffer_get_list(ctx, smp_load_acquire(&ctx->io_bl), bgid);
+ if (!bl || !bl->is_mmap)
+ return NULL;
/*
* Ensure the list is fully setup. Only strictly needed for RCU lookup
* via mmap, and in that case only for the array indexed groups. For
@@ -763,8 +765,6 @@ void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
*/
if (!smp_load_acquire(&bl->is_ready))
return NULL;
- if (!bl || !bl->is_mmap)
- return NULL;
return bl->buf_ring;
}