Re: [BUG bisect] kernel BUG at block/bio.c:1833 and fail to mount disk

[Nathan Chancellor]

On Thu, Jan 17, 2019 at 06:26:58PM +0800, Ming Lei wrote:
> On Wed, Jan 16, 2019 at 09:54:05AM +0100, Krzysztof Kozlowski wrote:
> > On Wed, 16 Jan 2019 at 09:52, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > >
> > > Hi,
> > >
> > > On today's next-20190116 I see a bug during boot:
> > > [ 6.843308] kernel BUG at ../block/bio.c:1833!
> > > [ 6.847723] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
> > > ...
> > > [ 7.543824] [<c044c144>] (bio_split) from [<00000000>] ( (null))
> > > [ 7.549881] Code: 13833b01 11c630bc e1a00006 e8bd8070 (e7f001f2)
> > >
> > > (not much in the calltrace)
> > > On all my boards. Also QEMU-arm fails.
> > >
> > 
> > I forgot the bisect commit:
> > 
> > 258cfdfaf7bd729e759a0a91fd00ac9794796ad3 is the first bad commit
> > commit 258cfdfaf7bd729e759a0a91fd00ac9794796ad3
> > Author: Ming Lei <ming.lei@xxxxxxxxxx>
> > Date:   Fri Jan 11 19:01:15 2019 +0800
> > 
> >     block: use bio_for_each_bvec() to compute multi-page bvec count
> > 
> > :040000 040000 d79b2e71d308650df4764ff644f29d3a24dbab96
> > 0a5d624843b805ee0c9fd9a7e2d5163f5b15b167 M block
> 
> It should be one 32-bit arch specific issue, I guess.
> 
> The following patch should fix this issue:
> 
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index dc4877eaf9f9..4dd7183de849 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -166,6 +166,9 @@ static unsigned get_max_segment_size(struct request_queue *q,
>  {
>  	unsigned long mask = queue_segment_boundary(q);
>  
> +	if (mask == BLK_SEG_BOUNDARY_MASK)
> +		return queue_max_segment_size(q);
> +
>  	return min_t(unsigned long, mask - (mask & offset) + 1,
>  		     queue_max_segment_size(q));
>  }
> 
> Thanks,
> Ming

Hi Ming,

We saw this issue on our CI as well: https://travis-ci.com/ClangBuiltLinux/continuous-integration/jobs/170724607

I added your patch and tested locally, it boots fine now.

Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx>

Thanks,
Nathan