From: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alexander Graf <agraf@suse.de>,
linux-nfs@vger.kernel.org, Jan Kara <jack@suse.cz>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML List <linux-kernel@vger.kernel.org>,
"J. Bruce Fields" <bfields@fieldses.org>,
anton@samba.org, skinsbursky@parallels.com, bfields@redhat.com,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [REGRESSION] nfsd crashing with 3.6.0-rc7 on PowerPC
Date: Tue, 2 Oct 2012 14:43:27 -0700 [thread overview]
Message-ID: <20121002214327.GA29218@linux.vnet.ibm.com> (raw)
In-Reply-To: <1349139509.3847.2.camel@pasglop>
Hi Ben,
On 02.10.2012 [10:58:29 +1000], Benjamin Herrenschmidt wrote:
> On Mon, 2012-10-01 at 16:03 +0200, Alexander Graf wrote:
> > Phew. Here we go :). It looks to be more of a PPC specific problem
> > than it appeared as at first:
>
> Ok, so I suspect the problem is the pushing down of the locks which
> breaks with iommu backends that have a separate flush callback. In
> that case, the flush moves out of the allocator lock.
>
> Now we do call flush before we return, still, but it becomes racy
> I suspect, but somebody needs to give it a closer look. I'm hoping
> Anton or Nish will later today.
Started looking into this. If your suspicion were accurate, wouldn't the
bisection have stopped at 0e4bc95d87394364f408627067238453830bdbf3
("powerpc/iommu: Reduce spinlock coverage in iommu_alloc and
iommu_free")?
Alex, the error is reproducible, right? Does it go away by reverting
that commit against mainline? Just trying to narrow down my focus.
Thanks,
Nish
WARNING: multiple messages have this Message-ID (diff)
From: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linux-nfs@vger.kernel.org, Jan Kara <jack@suse.cz>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Alexander Graf <agraf@suse.de>,
LKML List <linux-kernel@vger.kernel.org>,
"J. Bruce Fields" <bfields@fieldses.org>,
anton@samba.org, skinsbursky@parallels.com, bfields@redhat.com,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [REGRESSION] nfsd crashing with 3.6.0-rc7 on PowerPC
Date: Tue, 2 Oct 2012 14:43:27 -0700 [thread overview]
Message-ID: <20121002214327.GA29218@linux.vnet.ibm.com> (raw)
In-Reply-To: <1349139509.3847.2.camel@pasglop>
Hi Ben,
On 02.10.2012 [10:58:29 +1000], Benjamin Herrenschmidt wrote:
> On Mon, 2012-10-01 at 16:03 +0200, Alexander Graf wrote:
> > Phew. Here we go :). It looks to be more of a PPC specific problem
> > than it appeared as at first:
>
> Ok, so I suspect the problem is the pushing down of the locks which
> breaks with iommu backends that have a separate flush callback. In
> that case, the flush moves out of the allocator lock.
>
> Now we do call flush before we return, still, but it becomes racy
> I suspect, but somebody needs to give it a closer look. I'm hoping
> Anton or Nish will later today.
Started looking into this. If your suspicion were accurate, wouldn't the
bisection have stopped at 0e4bc95d87394364f408627067238453830bdbf3
("powerpc/iommu: Reduce spinlock coverage in iommu_alloc and
iommu_free")?
Alex, the error is reproducible, right? Does it go away by reverting
that commit against mainline? Just trying to narrow down my focus.
Thanks,
Nish
next prev parent reply other threads:[~2012-10-02 21:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-28 1:55 [REGRESSION] nfsd crashing with 3.6.0-rc7 on PowerPC Alexander Graf
2012-09-28 1:55 ` Alexander Graf
2012-09-28 2:04 ` Linus Torvalds
2012-09-28 2:04 ` Linus Torvalds
2012-09-28 2:19 ` Alexander Graf
2012-09-28 2:19 ` Alexander Graf
2012-09-28 15:10 ` J. Bruce Fields
2012-09-28 15:10 ` J. Bruce Fields
2012-09-28 15:34 ` Alexander Graf
2012-09-28 15:34 ` Alexander Graf
2012-10-01 14:03 ` Alexander Graf
2012-10-01 14:03 ` Alexander Graf
2012-10-01 15:21 ` J. Bruce Fields
2012-10-01 15:21 ` J. Bruce Fields
2012-10-02 0:58 ` Benjamin Herrenschmidt
2012-10-02 0:58 ` Benjamin Herrenschmidt
2012-10-02 21:43 ` Nishanth Aravamudan [this message]
2012-10-02 21:43 ` Nishanth Aravamudan
2012-10-02 21:47 ` Alexander Graf
2012-10-02 21:47 ` Alexander Graf
2012-10-02 22:17 ` Nishanth Aravamudan
2012-10-02 22:17 ` Nishanth Aravamudan
2012-10-02 22:31 ` Alexander Graf
2012-10-02 22:31 ` Alexander Graf
2012-10-04 0:26 ` Anton Blanchard
2012-10-04 0:26 ` Anton Blanchard
2012-10-04 4:57 ` [PATCH] powerpc/iommu: Fix multiple issues with IOMMU pools code Anton Blanchard
2012-10-04 4:57 ` Anton Blanchard
2012-10-04 10:54 ` Alexander Graf
2012-10-04 10:54 ` Alexander Graf
2012-10-03 4:22 ` [REGRESSION] nfsd crashing with 3.6.0-rc7 on PowerPC Benjamin Herrenschmidt
2012-10-03 4:22 ` Benjamin Herrenschmidt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121002214327.GA29218@linux.vnet.ibm.com \
--to=nacc@linux.vnet.ibm.com \
--cc=agraf@suse.de \
--cc=anton@samba.org \
--cc=benh@kernel.crashing.org \
--cc=bfields@fieldses.org \
--cc=bfields@redhat.com \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=skinsbursky@parallels.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.