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Subject: Re: mm: BUG in pgtable_pmd_page_dtor
References: <CACT4Y+Z0QqeO-fpc_tuStBGPWMwcK-gT-2q+tPmDpQDCkqYUiQ@mail.gmail.com>
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From: Vlastimil Babka <vbabka@suse.cz>
Message-ID: <2ff6eee6-8828-821a-7dde-c2f68da697a5@suse.cz>
Date: Fri, 25 Nov 2016 13:58:57 +0100
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To: Andrey Ryabinin <aryabinin@virtuozzo.com>, Dmitry Vyukov <dvyukov@google.com>, Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Michal Hocko <mhocko@suse.com>, Ingo Molnar <mingo@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, "linux-mm@kvack.org" <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, syzkaller <syzkaller@googlegroups.com>

On 11/25/2016 12:41 PM, Andrey Ryabinin wrote:
> 
> 
> On 11/25/2016 11:42 AM, Vlastimil Babka wrote:
> 
>>  	pr_emerg("page:%p count:%d mapcount:%d mapping:%p index:%#lx",
>>  		  page, page_ref_count(page), mapcount,
>> @@ -59,6 +61,21 @@ void __dump_page(struct page *page, const char *reason)
>>  
>>  	pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
>>  
>> +	pr_alert("raw struct page data:");
>> +	for (i = 0; i < sizeof(struct page) / sizeof(unsigned long); i++) {
>> +		unsigned long *word_ptr;
>> +
>> +		word_ptr = ((unsigned long *) page) + i;
>> +
>> +		if ((i % words_per_line) == 0) {
>> +			pr_cont("\n");
>> +			pr_alert(" %016lx", *word_ptr);
>> +		} else {
>> +			pr_cont(" %016lx", *word_ptr);
>> +		}
>> +	}
>> +	pr_cont("\n");
>> +
> 
> Single call to print_hex_dump() could replace this loop.

Ah, didn't know about that one, thanks!

This also addresses Kirill's comment:

-----8<-----