io_uring/register: use correct location for io_rings_layout

A previous consolidated the ring size etc calculations into
io_prepare_config(), but missed updating io_register_resize_rings()
correctly to use the calculated values. As a result, it ended up using
on-stack uninitialized values, and hence either failed validating the
size correctly, or just failed resizing because the sizes were random.

This caused failures in the liburing regression tests:

[...]
Running test resize-rings.t
resize=-7
test_basic 3000 failed
Test resize-rings.t failed with ret 1
Running test resize-rings.t /dev/sda
resize=-7
test_basic 3000 failed
Test resize-rings.t failed with ret 1
Running test resize-rings.t /dev/nvme1n1
resize=-7
test_basic 3000 failed
Test resize-rings.t failed with ret 1
Running test resize-rings.t /dev/dm-0
resize=-7
test_basic 3000 failed
Test resize-rings.t failed with ret 1

because io_create_region() would return -E2BIG because of unintialized
reg->size values.

Adjust the struct io_rings_layout rl pointer to point to the correct
location, and remove the (now dead) __rl on stack struct.

Fixes: eb76ff6a6829 ("io_uring: pre-calculate scq layout")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/register.c b/io_uring/register.c
index fc66a536448359e94b3a07c41de45a55c211304a..db42f98562c4e05d6ed16f7f216a103d8a09c5b0 100644 (file)
--- a/io_uring/register.c
+++ b/io_uring/register.c
@@ -403,7 +403,7 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg)
        struct io_ring_ctx_rings o = { }, n = { }, *to_free = NULL;
        unsigned i, tail, old_head;
        struct io_uring_params *p = &config.p;
-       struct io_rings_layout __rl, *rl = &__rl;
+       struct io_rings_layout *rl = &config.layout;
        int ret;
 
        memset(&config, 0, sizeof(config));