From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: netdev@vger.kernel.org, bugme-daemon@bugzilla.kernel.org,
pstaszewski@artcom.pl, linux-mm@kvack.org,
Christoph Lameter <clameter@sgi.com>
Subject: Re: [Bugme-new] [Bug 10318] New: WARNING: at arch/x86/mm/highmem_32.c:43 kmap_atomic_prot+0x87/0x184()
Date: Tue, 25 Mar 2008 21:23:50 +0100 [thread overview]
Message-ID: <20080325202350.GH15330@elte.hu> (raw)
In-Reply-To: <20080325105750.ff913a83.akpm@linux-foundation.org>
* Andrew Morton <akpm@linux-foundation.org> wrote:
> afacit what's happened is that someone is running __alloc_pages(...,
> __GFP_ZERO) from softirq context. But the __GFP_ZERO implementation
> uses KM_USER0 which cannot be used from softirq context because
> non-interrupt code on this CPU might be using the same kmap slot.
>
> Can anyone thing of anything which recently changed in either
> networking core or e1000e which would have triggered this?
>
> I think the core MM code is being doubly dumb here.
>
> a) We should be able to use __GFP_ZERO from all copntexts.
>
> b) it's not a highmem page anyway, so we won't be using that kmap
> slot.
i think this came up before (with kzalloc()) and the MM code should have
been fixed to not even attempt a kmap_atomic(), instead of working it
around in the callsite or in the kmap_atomic() code.
Ingo
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prev parent reply other threads:[~2008-03-25 20:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-10318-10286@http.bugzilla.kernel.org/>
2008-03-25 17:57 ` Andrew Morton
2008-03-25 18:44 ` Eric Dumazet
2008-03-25 19:01 ` Christoph Lameter
2008-03-25 20:23 ` Ingo Molnar [this message]
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