On Wed, Jan 04, 2023 at 07:37:48PM -0800, Kees Cook wrote: > Zero-length arrays are deprecated[1]. Replace struct io_uring_buf_ring's > "bufs" with a flexible array member. (How is the size of this array > verified?) Detected with GCC 13, using -fstrict-flex-arrays=3: > > In function 'io_ring_buffer_select', > inlined from 'io_buffer_select' at io_uring/kbuf.c:183:10: > io_uring/kbuf.c:141:23: warning: array subscript 255 is outside the bounds of an interior zero-length array 'struct io_uring_buf[0]' [-Wzero-length-bounds] > 141 | buf = &br->bufs[head]; > | ^~~~~~~~~~~~~~~ > In file included from include/linux/io_uring.h:7, > from io_uring/kbuf.c:10: > include/uapi/linux/io_uring.h: In function 'io_buffer_select': > include/uapi/linux/io_uring.h:628:41: note: while referencing 'bufs' > 628 | struct io_uring_buf bufs[0]; > | ^~~~ > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays > > Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") > Cc: Jens Axboe <axboe@xxxxxxxxx> > Cc: Pavel Begunkov <asml.silence@xxxxxxxxx> > Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx Build problem aside, why is this a stable kernel issue? thanks, greg k-h
