From: Yang Shi <yang.shi@linux.alibaba.com>
To: Li Xinhai <lixinhai.lxh@gmail.com>, akpm <akpm@linux-foundation.org>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: mempolicy: use VM_BUG_ON_VMA in queue_pages_test_walk()
Date: Wed, 15 Jan 2020 09:27:07 -0800 [thread overview]
Message-ID: <2a9ad6d6-af98-987a-0878-6058702db912@linux.alibaba.com> (raw)
In-Reply-To: <2020011520081970082765@gmail.com>
On 1/15/20 4:08 AM, Li Xinhai wrote:
> On 2020-01-15 at 14:09 Yang Shi wrote:
>> The VM_BUG_ON() is already used by queue_pages_test_walk(), it sounds
>> better to dump more debug information by using VM_BUG_ON_VMA() to help
>> debugging.
>>
>> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
> The .test_walk() is to be called from pagewalk with the rule that 'start'
> and 'end' must within range of vma, in case the rule is broke, we detect
> it. This is not quite relevant to a bug of particular vma.
But when you run into VMA range check failure, isn't it helpful to dump
the VMA range information to ease debugging? And, VM_BUG_ON is already
used in the code, I'm supposed the users may prefer more debug
information dumped for debug kernel.
>
>> ---
>> mm/mempolicy.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
>> index 067cf7d..801d45d 100644
>> --- a/mm/mempolicy.c
>> +++ b/mm/mempolicy.c
>> @@ -621,7 +621,7 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
>> unsigned long flags = qp->flags;
>>
>> /* range check first */
>> - VM_BUG_ON((vma->vm_start > start) || (vma->vm_end < end));
>> + VM_BUG_ON_VMA((vma->vm_start > start) || (vma->vm_end < end), vma);
>>
>> if (!qp->first) {
>> qp->first = vma;
>> --
>> 1.8.3.1
>>
> >
next prev parent reply other threads:[~2020-01-15 17:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 6:09 [PATCH] mm: mempolicy: use VM_BUG_ON_VMA in queue_pages_test_walk() Yang Shi
2020-01-15 12:08 ` Li Xinhai
2020-01-15 17:27 ` Yang Shi [this message]
2020-01-16 15:52 ` Li Xinhai
2020-01-27 16:59 ` Yang Shi
2020-01-27 18:17 ` Qian Cai
2020-01-27 19:57 ` Yang Shi
2020-01-27 20:23 ` Qian Cai
2020-02-14 5:26 ` Andrew Morton
2020-02-14 12:24 ` Qian Cai
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