io_uring: implement compat handling for IORING_REGISTER_IOWQ_AFF

commit 0f5e4b83b37a96e3643951588ed7176b9b187c0a upstream.

Similarly to the way it is done im mbind syscall.

Cc: stable@vger.kernel.org # 5.14
Fixes: fe76421d1da1dcdb ("io_uring: allow user configurable IO thread CPU affinity")
Signed-off-by: Eugene Syromiatnikov <esyr@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 07f1eb8ec89f8b71e30d9133eeb0e458a173bba3..13001cd22bbaca75512eb7520d83f768de2461a6 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10799,7 +10799,15 @@ static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx,
        if (len > cpumask_size())
                len = cpumask_size();
 
-       if (copy_from_user(new_mask, arg, len)) {
+       if (in_compat_syscall()) {
+               ret = compat_get_bitmap(cpumask_bits(new_mask),
+                                       (const compat_ulong_t __user *)arg,
+                                       len * 8 /* CHAR_BIT */);
+       } else {
+               ret = copy_from_user(new_mask, arg, len);
+       }
+
+       if (ret) {
                free_cpumask_var(new_mask);
                return -EFAULT;
        }