From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Hugh Dickins <hughd@google.com>,
Ingo Korb <ingo.korb@tu-dortmund.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Ning Qu <quning@google.com>, Dave Jones <davej@redhat.com>,
Sasha Levin <sasha.levin@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: PROBLEM: repeated remap_file_pages on tmpfs triggers bug on process exit
Date: Tue, 15 Jul 2014 13:55:47 +0300 (EEST) [thread overview]
Message-ID: <20140715105547.C4832E00A3@blue.fi.intel.com> (raw)
In-Reply-To: <CALYGNiM9Fu9-i7hXMQNTUP69RfydN+2NqO29wZYd+4Gn25GbCQ@mail.gmail.com>
Konstantin Khlebnikov wrote:
> It seems boundng logic in do_fault_around is wrong:
>
> start_addr = max(address & fault_around_mask(), vma->vm_start);
> off = ((address - start_addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
> pte -= off;
> pgoff -= off;
>
> Ok, off <= 511, but it might be bigger than pte offset in pte table.
I don't see how it possible: fault_around_mask() cannot be more than 0x1ff000
(x86-64, fault_around_bytes == 2M). It means start_addr will be aligned to 2M
boundary in this case which is start of the page table pte belong to.
Do I miss something?
--
Kirill A. Shutemov
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next prev parent reply other threads:[~2014-07-15 10:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-14 12:58 Ingo Korb
2014-07-14 19:22 ` Hugh Dickins
2014-07-14 20:13 ` Konstantin Khlebnikov
2014-07-15 9:55 ` [PATCH] mm: fix faulting range in do_fault_around Konstantin Khlebnikov
2014-07-15 10:55 ` Kirill A. Shutemov [this message]
2014-07-15 11:33 ` PROBLEM: repeated remap_file_pages on tmpfs triggers bug on process exit Konstantin Khlebnikov
2014-07-15 11:54 ` Kirill A. Shutemov
2014-07-15 20:46 ` Hugh Dickins
2014-07-15 11:58 ` [PATCH] mm: do not call do_fault_around for non-linear fault Konstantin Khlebnikov
2014-07-15 15:29 ` Ingo Korb
2014-07-15 20:42 ` Andrew Morton
2014-07-15 21:07 ` Konstantin Khlebnikov
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