This is a note to let you know that I've just added the patch titled
io_uring/kbuf: check for buffer list readiness after NULL check
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
io_uring-kbuf-check-for-buffer-list-readiness-after-.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2c028a4239019217df25663fde980a0ab690c5c6
Author: Jens Axboe <axboe@xxxxxxxxx>
Date: Tue Dec 5 07:02:13 2023 -0700
io_uring/kbuf: check for buffer list readiness after NULL check
[ Upstream commit 9865346b7e8374b57f1c3ccacdc77846c6352ff4 ]
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@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 12eec4778c5b1..e8516f3bbbaaa 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -743,6 +743,8 @@ 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
@@ -750,8 +752,6 @@ 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;
}
