io_uring: set ctx sq/cq entry count earlier

commit bd74048108c179cea0ff52979506164c80f29da7 upstream.

If we hit an earlier error path in io_uring_create(), then we will have
accounted memory, but not set ctx->{sq,cq}_entries yet. Then when the
ring is torn down in error, we use those values to unaccount the memory.

Ensure we set the ctx entries before we're able to hit a potential error
path.

Cc: stable@vger.kernel.org
Reported-by: Tomáš Chaloupka <chalucha@gmail.com>
Tested-by: Tomáš Chaloupka <chalucha@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 04604202502553f844117c0d00103acdc31d6bc1..dc3bb06efdd6ad8484d8021432c563c4049984e7 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3857,6 +3857,10 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
        struct io_rings *rings;
        size_t size, sq_array_offset;
 
+       /* make sure these are sane, as we already accounted them */
+       ctx->sq_entries = p->sq_entries;
+       ctx->cq_entries = p->cq_entries;
+
        size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
        if (size == SIZE_MAX)
                return -EOVERFLOW;
@@ -3873,8 +3877,6 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
        rings->cq_ring_entries = p->cq_entries;
        ctx->sq_mask = rings->sq_ring_mask;
        ctx->cq_mask = rings->cq_ring_mask;
-       ctx->sq_entries = rings->sq_ring_entries;
-       ctx->cq_entries = rings->cq_ring_entries;
 
        size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
        if (size == SIZE_MAX) {