[PATCH 1/2] io_uring/uring_cmd: don't assume io_uring_cmd_data layout

Caleb Sander Mateos
2025-02-12T20:46:05Z

eaf72f7b414f ("io_uring/uring_cmd: cleanup struct io_uring_cmd_data
layout") removed most of the places assuming struct io_uring_cmd_data
has sqes as its first field. However, the EAGAIN case in io_uring_cmd()
still compares ioucmd->sqe to the struct io_uring_cmd_data pointer using
a void * cast. Since fa3595523d72 ("io_uring: get rid of alloc cache
init_once handling"), sqes is no longer io_uring_cmd_data's first field.
As a result, the pointers will always compare unequal and memcpy() may
be called with the same source and destination.

Replace the incorrect void * cast with the address of the sqes field.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: eaf72f7b414f ("io_uring/uring_cmd: cleanup struct io_uring_cmd_data layout")
---
io_uring/uring_cmd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index 1f6a82128b47..cfb22e1de0e7 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -250,11 +250,11 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)

ret = file->f_op->uring_cmd(ioucmd, issue_flags);
if (ret == -EAGAIN) {
struct io_uring_cmd_data *cache = req->async_data;

- if (ioucmd->sqe != (void *) cache)
+ if (ioucmd->sqe != cache->sqes)
memcpy(cache->sqes, ioucmd->sqe, uring_sqe_size(req->ctx));
return -EAGAIN;
} else if (ret == -EIOCBQUEUED) {
return -EIOCBQUEUED;
}
--
2.45.2