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Re: [PATCH] bio allocation failure due to bio_get_nr_vecs()

To: Jens Axboe <axboe@xxxxxxxxx>
Subject: Re: [PATCH] bio allocation failure due to bio_get_nr_vecs()
From: Bernd Schubert <bernd.schubert@xxxxxxxxxxxxxxxxxx>
Date: Fri, 11 May 2012 16:44:03 +0200
Cc: "linux-fsdevel@xxxxxxxxxxxxxxx" <linux-fsdevel@xxxxxxxxxxxxxxx>, linux-xfs@xxxxxxxxxxx, sandeen@xxxxxxxxxxx, Kent Overstreet <kent.overstreet@xxxxxxxxx>, Tejun Heo <tj@xxxxxxxxxx>
In-reply-to: <4FAD23F7.2080605@xxxxxxxxx>
References: <jognqm$o21$1@xxxxxxxxxxxxxxx> <4FABF01E.7080303@xxxxxxxxxxxxxxxxxx> <4FAD18D4.3090102@xxxxxxxxxxxxxxxxxx> <4FAD23F7.2080605@xxxxxxxxx>
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1
On 05/11/2012 04:36 PM, Jens Axboe wrote:
On 05/11/2012 03:49 PM, Bernd Schubert wrote:
The number of bio_get_nr_vecs() is passed down via bio_alloc() to
bvec_alloc_bs(), which fails the bio allocation if
nr_iovecs>  BIO_MAX_PAGES. For the underlying caller this causes an
unexpected bio allocation failure.
Limiting to queue_max_segments() is not sufficient, as max_segments
also might be very large.

bvec_alloc_bs(gfp_mask, nr_iovecs, ) =>  NULL when nr_iovecs>  BIO_MAX_PAGES
bio_alloc_bioset(gfp_mask, nr_iovecs, ...)
bio_alloc(GFP_NOIO, nvecs)
xfs_alloc_ioend_bio()

Thanks, looks sane. Applied.


Great, thanks! Should we CC linux-stable for commit 5abebfdd02450fa1349daacf242e70b3736581e3 and this one, as I got a hard kernel panic?


Thanks,
Bernd

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