On Mon, 3 Oct 2022 09:35:34 -0400, Brian Foster wrote:
> request_queue->queue_flags is unsigned long, which is 8-bytes on
> 64-bit architectures. Most queue flag modifications occur through
> bit field helpers, but default flags can be logically OR'd via the
> QUEUE_FLAG_MQ_DEFAULT mask. If this mask happens to include bit 31,
> the assignment can sign extend the field and set all upper 32 bits.
>
> This exact problem has been observed on a downstream kernel that
> happens to use bit 31 for QUEUE_FLAG_NOWAIT. This is not an
> immediate problem for current upstream because bit 31 is not
> included in the default flag assignment (and is not used at all,
> actually). Regardless, fix up the QUEUE_FLAG_MQ_DEFAULT mask
> definition to avoid the landmine in the future.
>
> [...]
Applied, thanks!
[1/1] block: avoid sign extend problem with default queue flags mask
commit: ca5eebda3e1c1a58a1c5a337da393ed6734593e3
Best regards,
--
Jens Axboe
