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Subject: Re: Bug in commit aa511ff8218b ("badblocks: switch to the improved
 badblock handling
From: Coly Li <colyli@suse.de>
In-Reply-To: <6585d5fda5183_9f731294b9@iweiny-mobl.notmuch>
Date: Sat, 23 Dec 2023 14:52:07 +0800
Cc: Dan Williams <dan.j.williams@intel.com>,
 Jens Axboe <axboe@kernel.dk>,
 Xiao Ni <xni@redhat.com>,
 Geliang Tang <geliang.tang@suse.com>,
 Hannes Reinecke <hare@suse.de>,
 NeilBrown <neilb@suse.de>,
 Vishal L Verma <vishal.l.verma@intel.com>,
 linux-block@vger.kernel.org,
 nvdimm@lists.linux.dev,
 linux-kernel@vger.kernel.org
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Message-Id: <270BD884-EF31-491C-9339-5D9ADF3BC694@suse.de>
References: <6585d5fda5183_9f731294b9@iweiny-mobl.notmuch>
To: Ira Weiny <ira.weiny@intel.com>


> 2023=E5=B9=B412=E6=9C=8823=E6=97=A5 02:31=EF=BC=8CIra Weiny =
<ira.weiny@intel.com> =E5=86=99=E9=81=93=EF=BC=9A
>=20
> Coly,
>=20
> Yesterday I noticed that a few of our nvdimm tests were failing.  I =
bisected
> the problem to the following commit.
>=20
> aa511ff8218b ("badblocks: switch to the improved badblock handling =
code")=20
>=20
> Reverting this patch fixed our tests.
>=20
> I've also dug into the code a bit and I believe the algorithm for
> badblocks_check() is broken (not yet sure about the other calls).  At =
the
> very least I see the bb->p pointer being indexed with '-1'.  :-(
>=20
> I did notice that this work was due to a bug report in badblock_set().
> Therefore, I'm not sure of that severity of that fix is vs a revert.  =
But
> at this point I'm not seeing an easy fix so I'm in favor of a revert.

Hi Ira,

Thanks for the information reported. Let me look into the situation now.

Coly Li