From: Ingo Molnar <mingo@elte.hu>
To: Li Zefan <lizf@cn.fujitsu.com>,
Jaswinder Singh Rajput <jaswinder@kernel.org>,
Nick Piggin <npiggin@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
Mike Travis <travis@sgi.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] kernel BUG at arch/x86/kernel/tlb_32.c:130!
Date: Tue, 20 Jan 2009 08:54:40 +0100 [thread overview]
Message-ID: <20090120075440.GA29426@elte.hu> (raw)
In-Reply-To: <49756F44.6040801@cn.fujitsu.com>
* Li Zefan <lizf@cn.fujitsu.com> wrote:
> I was using mmotm 2009-01-16-16-18, and I ran into this BUG,
> the line is:
> BUG_ON(cpumask_empty(cpumask));
>
> I suspect it is caused by:
>
> commit 4595f9620cda8a1e973588e743cf5f8436dd20c6
> Author: Rusty Russell <rusty@rustcorp.com.au>
> Date: Sat Jan 10 21:58:09 2009 -0800
>
> x86: change flush_tlb_others to take a const struct cpumask
>
> Impact: reduce stack usage, use new cpumask API.
Jaswinder reported a similar crash.
Mike, Rusty, what's going on with this commit? Why does this code:
+ if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
+ flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL);
Assume that mm->cpu_vm_mask wont change? TLB flushes go async and the MM's
schedulability is not locked during that. I.e. mm->cpu_vm_mask can change
under you while the TLB flush IPIs are flying around - while when the
cpumask was passed on-stack this wouldnt happen.
Ingo
next prev parent reply other threads:[~2009-01-20 7:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 6:29 Li Zefan
2009-01-20 7:54 ` Ingo Molnar [this message]
2009-01-20 8:17 ` Ingo Molnar
2009-01-20 8:20 ` Li Zefan
2009-01-20 8:29 ` Ingo Molnar
2009-01-20 13:44 ` Jaswinder Singh Rajput
2009-01-21 0:44 ` Li Zefan
2009-01-21 1:01 ` Jaswinder Singh Rajput
2009-01-20 18:17 ` Mike Travis
2009-01-20 7:56 ` Laurent Riffard
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