Subject: Re: [PATCH v2 3/5] mmu_notifiers: Call invalidate_range() when invalidating TLBs

From: Alistair Popple <[email-masked]>
Date: Tue, 25 Jul 2023 10:20:52 +1000

Luis Chamberlain <[email-masked]> writes:

>> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
>> index 837e4a50281a..79c46da919b9 100644
>> --- a/arch/x86/include/asm/tlbflush.h
>> +++ b/arch/x86/include/asm/tlbflush.h
>> @@ -4,6 +4,7 @@
>>  
>>  #include <linux/mm_types.h>
>>  #include <linux/sched.h>
>> +#include <linux/mmu_notifier.h>
>>  
>>  #include <asm/processor.h>
>>  #include <asm/cpufeature.h>
>> @@ -282,6 +283,7 @@ static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *b
>>  {
>>  	inc_mm_tlb_gen(mm);
>>  	cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm));
>> +	mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL);
>>  }
>>  
>>  static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm)
>> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
>> index 0b990fb56b66..2d253919b3e8 100644
>> --- a/arch/x86/mm/tlb.c
>> +++ b/arch/x86/mm/tlb.c
>> @@ -1265,7 +1265,6 @@ void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
>>  
>>  	put_flush_tlb_info();
>>  	put_cpu();
>> -	mmu_notifier_arch_invalidate_secondary_tlbs(current->mm, 0, -1UL);
>>  }
>>  
>>  /*
>
> This patch also fixes a regression introduced on linux-next, the same
> crash on arch_tlbbatch_flush() is reproducible with fstests generic/176
> on XFS. This patch fixes that regression [0]. This should also close out
> the syzbot crash too [1]
>
> [0] https://gist.github.com/mcgrof/b37fc8cf7e6e1b3935242681de1a83e2
> [1] https://lore.kernel.org/all/[email-masked]/
>
> Tested-by: Luis Chamberlain <[email-masked]>

Thanks Luis. The above fix/respin is already in yesterdays linux-next
(next-20230724) so hopefully you are no longer seeing issues.

>   Luis