| Message ID | 20220613101157.3687-4-dylany@fb.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring: fixes for provided buffer ring | expand |
diff --git a/fs/io_uring.c b/fs/io_uring.c index 6eea18e8330c..85b116ddfd2a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -13002,6 +13002,10 @@ static int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) if (!is_power_of_2(reg.ring_entries)) return -EINVAL; + /* cannot disambiguate full vs empty due to head/tail size */ + if (reg.ring_entries >= 65536) + return -EINVAL; + if (unlikely(reg.bgid < BGID_ARRAY && !ctx->io_bl)) { int ret = io_init_bl_list(ctx); if (ret)
The type of head and tail do not allow more than 2^15 entries in a provided buffer ring, so do not allow this. At 2^16 while each entry can be indexed, there is no way to disambiguate full vs empty. Signed-off-by: Dylan Yudaken <dylany@fb.com> --- fs/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+)