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Date: Mon, 15 Jun 2026 11:19:43 -0600
From: Keith Busch <kbusch@kernel.org>
To: "Dr. David Alan Gilbert" <linux@treblig.org>
Cc: linux-block@vger.kernel.org, dm-devel@lists.linux.dev
Subject: Re: Repeatable, raid1+O_DIRECT, hang/warn
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On Mon, Jun 15, 2026 at 04:37:39PM +0000, Dr. David Alan Gilbert wrote:
> Hi Keith,
>   Thanks for the patch, alas it doesn't seem to be helping here;
>  the first warn is still the same
> and it still hangs the test process hard and eventually BUGs at
> 
> void blk_mq_end_request(struct request *rq, blk_status_t error)
> {
>         if (blk_update_request(rq, error, blk_rq_bytes(rq)))
>                 BUG();

Oh, that was not expected.

What is the dma alignment requirement of your backing devices? You can
find the attribute for sda at /sys/block/sda/queue/dma_alignment. I'm
expecting 511, but just want to double check.