From: Hugh Dickins <hugh@veritas.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Gautham R Shenoy <ego@in.ibm.com>
Subject: Re: [PATCH 0/2] lockdep vs recursive read locks
Date: Thu, 13 Mar 2008 11:25:28 +0000 (GMT) [thread overview]
Message-ID: <Pine.LNX.4.64.0803131124220.17196@blonde.site> (raw)
In-Reply-To: <20080312120920.929901000@chello.nl>
On Wed, 12 Mar 2008, Peter Zijlstra wrote:
> We seemed to have some lockdep trouble wrt recursive read locks. Today Gautham
> asked me some specific questions about it, which led to these patches.
>
> IIRC Hugh ran into something similar a while back. This hopefully fixes it.
Hmm, I don't remember that myself: can you jog my memory?
What I do remember is that when I fixed madvise(MADV_REMOVE i.e. holepunch)
not to hold mmap_sem (at that time down_write but today down_read, though
would still be bad) across vmtruncate_range which takes i_mutex (contrast
writing from an unfaulted area that takes i_mutex then down_read mmap_sem),
Ingo asked me offline if lockdep caught that and it didn't. Just tried
again now, with your patches applied, and madvise_remove restored to its
old misbehaviour, and it looks like lockdep still doesn't catch it
(but suspect me of pilot error if you find otherwise).
Hugh
next prev parent reply other threads:[~2008-03-13 11:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-12 12:09 Peter Zijlstra
2008-03-12 12:09 ` [PATCH 1/2] lockdep: fix recursive read lock validation Peter Zijlstra
2008-03-12 20:26 ` Gautham R Shenoy
2008-03-12 12:09 ` [PATCH 2/2] lockdep: fix fib_hash softirq inversion Peter Zijlstra
2008-03-13 3:50 ` [PATCH] net/lockdep: Make nl_table_lock read acquire softirq safe Gautham R Shenoy
2008-03-13 6:08 ` [PATCH 2/2] lockdep: fix fib_hash softirq inversion David Miller
2008-03-13 9:40 ` Arjan van de Ven
2008-03-13 11:25 ` Hugh Dickins [this message]
2008-03-14 7:35 ` [PATCH 0/2] lockdep vs recursive read locks Peter Zijlstra
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