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From: Vipin K Parashar <vipin@linux.vnet.ibm.com>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH] KVM: PPC: Book3S: Ratelimit copy data failure error messages
Date: Thu, 16 Feb 2017 16:03:09 +0530	[thread overview]
Message-ID: <56ada2fe-9ed0-2e53-1d6b-ac8571c23ff4@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170216053159.GD19110@fergus.ozlabs.ibm.com>



On Thursday 16 February 2017 11:01 AM, Paul Mackerras wrote:
> On Tue, Feb 14, 2017 at 11:42:21AM +0530, Vipin K Parashar wrote:
>> kvm_ppc_mmu_book3s_32/64 xlat() log "KVM can't copy data" error
>> upon failing to copy user data to kernel space. This floods kernel
>> log once such fails occur in short time period. Ratelimit this
>> error to avoid flooding kernel logs upon copy data failures.
>>
>> Signed-off-by: Vipin K Parashar <vipin@linux.vnet.ibm.com>
>> ---
>>   arch/powerpc/kvm/book3s_32_mmu.c | 3 ++-
>>   arch/powerpc/kvm/book3s_64_mmu.c | 3 ++-
>>   2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_32_mmu.c b/arch/powerpc/kvm/book3s_32_mmu.c
>> index a2eb6d3..ca8f960 100644
>> --- a/arch/powerpc/kvm/book3s_32_mmu.c
>> +++ b/arch/powerpc/kvm/book3s_32_mmu.c
>> @@ -224,7 +224,8 @@ static int kvmppc_mmu_book3s_32_xlate_pte(struct kvm_vcpu *vcpu, gva_t eaddr,
>>   	ptem = kvmppc_mmu_book3s_32_get_ptem(sre, eaddr, primary);
>>
>>   	if(copy_from_user(pteg, (void __user *)ptegp, sizeof(pteg))) {
>> -		printk(KERN_ERR "KVM: Can't copy data from 0x%lx!\n", ptegp);
>> +		if (printk_ratelimit())
>> +			printk(KERN_ERR "KVM: Can't copy data from 0x%lx!\n", ptegp);
> I found this in include/linux/printk.h:
>
> /*
>   * Please don't use printk_ratelimit(), because it shares ratelimiting state
>   * with all other unrelated printk_ratelimit() callsites.  Instead use
>   * printk_ratelimited() or plain old __ratelimit().
>   */
>
> It does seem that using printk_ratelimited(KERN_ERR ...) or the
> equivalent pr_err_ratelimited(...) would be a better option.

Thanks!! Paul.
Will send out v2 with above changes.

> Paul.
>

WARNING: multiple messages have this Message-ID (diff)
From: Vipin K Parashar <vipin@linux.vnet.ibm.com>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH] KVM: PPC: Book3S: Ratelimit copy data failure error messages
Date: Thu, 16 Feb 2017 10:45:09 +0000	[thread overview]
Message-ID: <56ada2fe-9ed0-2e53-1d6b-ac8571c23ff4@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170216053159.GD19110@fergus.ozlabs.ibm.com>



On Thursday 16 February 2017 11:01 AM, Paul Mackerras wrote:
> On Tue, Feb 14, 2017 at 11:42:21AM +0530, Vipin K Parashar wrote:
>> kvm_ppc_mmu_book3s_32/64 xlat() log "KVM can't copy data" error
>> upon failing to copy user data to kernel space. This floods kernel
>> log once such fails occur in short time period. Ratelimit this
>> error to avoid flooding kernel logs upon copy data failures.
>>
>> Signed-off-by: Vipin K Parashar <vipin@linux.vnet.ibm.com>
>> ---
>>   arch/powerpc/kvm/book3s_32_mmu.c | 3 ++-
>>   arch/powerpc/kvm/book3s_64_mmu.c | 3 ++-
>>   2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_32_mmu.c b/arch/powerpc/kvm/book3s_32_mmu.c
>> index a2eb6d3..ca8f960 100644
>> --- a/arch/powerpc/kvm/book3s_32_mmu.c
>> +++ b/arch/powerpc/kvm/book3s_32_mmu.c
>> @@ -224,7 +224,8 @@ static int kvmppc_mmu_book3s_32_xlate_pte(struct kvm_vcpu *vcpu, gva_t eaddr,
>>   	ptem = kvmppc_mmu_book3s_32_get_ptem(sre, eaddr, primary);
>>
>>   	if(copy_from_user(pteg, (void __user *)ptegp, sizeof(pteg))) {
>> -		printk(KERN_ERR "KVM: Can't copy data from 0x%lx!\n", ptegp);
>> +		if (printk_ratelimit())
>> +			printk(KERN_ERR "KVM: Can't copy data from 0x%lx!\n", ptegp);
> I found this in include/linux/printk.h:
>
> /*
>   * Please don't use printk_ratelimit(), because it shares ratelimiting state
>   * with all other unrelated printk_ratelimit() callsites.  Instead use
>   * printk_ratelimited() or plain old __ratelimit().
>   */
>
> It does seem that using printk_ratelimited(KERN_ERR ...) or the
> equivalent pr_err_ratelimited(...) would be a better option.

Thanks!! Paul.
Will send out v2 with above changes.

> Paul.
>


  reply	other threads:[~2017-02-16 10:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-13 18:56 [PATCH] KVM: PPC: Book3S: Ratelimit copy data failure error messages Vipin K Parashar
2017-02-14  6:12 ` Vipin K Parashar
2017-02-14  6:24   ` Vipin K Parashar
2017-02-16  5:31   ` Paul Mackerras
2017-02-16  5:31     ` Paul Mackerras
2017-02-16 10:33     ` Vipin K Parashar [this message]
2017-02-16 10:45       ` Vipin K Parashar
2017-02-14  6:20 ` Vipin K Parashar
2017-02-23  9:11   ` Vipin K Parashar

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