From: Eugene Syromiatnikov <esyr@xxxxxxxxxx> commit 0f5e4b83b37a96e3643951588ed7176b9b187c0a upstream. Similarly to the way it is done im mbind syscall. Cc: stable@xxxxxxxxxxxxxxx # 5.14 Fixes: fe76421d1da1dcdb ("io_uring: allow user configurable IO thread CPU affinity") Signed-off-by: Eugene Syromiatnikov <esyr@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -10799,7 +10799,15 @@ static __cold int io_register_iowq_aff(s 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; }