Messages in this thread | | | Date | Tue, 20 Jan 2009 08:54:40 +0100 | From | Ingo Molnar <> | Subject | Re: [BUG] kernel BUG at arch/x86/kernel/tlb_32.c:130! |
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* 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
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