From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: wei.guo.simon@gmail.com
Cc: linux-mm@kvack.org, Alexey Klimov <klimov.linux@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Eric B Munson <emunson@akamai.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@suse.com>, Shuah Khan <shuah@kernel.org>,
Thierry Reding <treding@nvidia.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH 2/4] mm: mlock: avoid increase mm->locked_vm on mlock() when already mlock2(,MLOCK_ONFAULT)
Date: Tue, 30 Aug 2016 14:36:44 +0300 [thread overview]
Message-ID: <20160830113644.GB32187@node.shutemov.name> (raw)
In-Reply-To: <1472554781-9835-3-git-send-email-wei.guo.simon@gmail.com>
On Tue, Aug 30, 2016 at 06:59:39PM +0800, wei.guo.simon@gmail.com wrote:
> From: Simon Guo <wei.guo.simon@gmail.com>
>
> When one vma was with flag VM_LOCKED|VM_LOCKONFAULT (by invoking
> mlock2(,MLOCK_ONFAULT)), it can again be populated with mlock() with
> VM_LOCKED flag only.
>
> There is a hole in mlock_fixup() which increase mm->locked_vm twice even
> the two operations are on the same vma and both with VM_LOCKED flags.
>
> The issue can be reproduced by following code:
> mlock2(p, 1024 * 64, MLOCK_ONFAULT); //VM_LOCKED|VM_LOCKONFAULT
> mlock(p, 1024 * 64); //VM_LOCKED
> Then check the increase VmLck field in /proc/pid/status(to 128k).
>
> When vma is set with different vm_flags, and the new vm_flags is with
> VM_LOCKED, it is not necessarily be a "new locked" vma. This patch
> corrects this bug by prevent mm->locked_vm from increment when old
> vm_flags is already VM_LOCKED.
>
> Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: wei.guo.simon@gmail.com
Cc: linux-mm@kvack.org, Alexey Klimov <klimov.linux@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Eric B Munson <emunson@akamai.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@suse.com>, Shuah Khan <shuah@kernel.org>,
Thierry Reding <treding@nvidia.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH 2/4] mm: mlock: avoid increase mm->locked_vm on mlock() when already mlock2(,MLOCK_ONFAULT)
Date: Tue, 30 Aug 2016 14:36:44 +0300 [thread overview]
Message-ID: <20160830113644.GB32187@node.shutemov.name> (raw)
In-Reply-To: <1472554781-9835-3-git-send-email-wei.guo.simon@gmail.com>
On Tue, Aug 30, 2016 at 06:59:39PM +0800, wei.guo.simon@gmail.com wrote:
> From: Simon Guo <wei.guo.simon@gmail.com>
>
> When one vma was with flag VM_LOCKED|VM_LOCKONFAULT (by invoking
> mlock2(,MLOCK_ONFAULT)), it can again be populated with mlock() with
> VM_LOCKED flag only.
>
> There is a hole in mlock_fixup() which increase mm->locked_vm twice even
> the two operations are on the same vma and both with VM_LOCKED flags.
>
> The issue can be reproduced by following code:
> mlock2(p, 1024 * 64, MLOCK_ONFAULT); //VM_LOCKED|VM_LOCKONFAULT
> mlock(p, 1024 * 64); //VM_LOCKED
> Then check the increase VmLck field in /proc/pid/status(to 128k).
>
> When vma is set with different vm_flags, and the new vm_flags is with
> VM_LOCKED, it is not necessarily be a "new locked" vma. This patch
> corrects this bug by prevent mm->locked_vm from increment when old
> vm_flags is already VM_LOCKED.
>
> Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
--
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next prev parent reply other threads:[~2016-08-30 11:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-30 10:59 [PATCH 0/4] mm: mlock: fix some locked_vm counting issues wei.guo.simon
2016-08-30 10:59 ` wei.guo.simon
2016-08-30 10:59 ` [PATCH 1/4] mm: mlock: check against vma for actual mlock() size wei.guo.simon
2016-08-30 10:59 ` wei.guo.simon
2016-08-30 11:35 ` Kirill A. Shutemov
2016-08-30 11:35 ` Kirill A. Shutemov
2016-08-30 10:59 ` [PATCH 2/4] mm: mlock: avoid increase mm->locked_vm on mlock() when already mlock2(,MLOCK_ONFAULT) wei.guo.simon
2016-08-30 10:59 ` wei.guo.simon
2016-08-30 11:36 ` Kirill A. Shutemov [this message]
2016-08-30 11:36 ` Kirill A. Shutemov
2016-08-30 10:59 ` [PATCH 3/4] selftest: split mlock2_ funcs into separate mlock2.h wei.guo.simon
2016-08-30 10:59 ` wei.guo.simon
2016-08-30 10:59 ` [PATCH 4/4] selftests/vm: add test for mlock() when areas are intersected wei.guo.simon
2016-08-30 10:59 ` wei.guo.simon
2016-08-31 23:14 ` David Rientjes
2016-08-31 23:14 ` David Rientjes
2016-09-01 7:14 ` Simon Guo
2016-09-01 7:14 ` Simon Guo
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