From: Li Zefan <lizefan@huawei.com>
To: Davidlohr Bueso <davidlohr@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Michel Lespinasse <walken@google.com>,
Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
"Norton, Scott J" <scott.norton@hp.com>,
linux-mm <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4] mm: per-thread vma caching
Date: Fri, 14 Mar 2014 11:05:51 +0800 [thread overview]
Message-ID: <5322720F.1030706@huawei.com> (raw)
In-Reply-To: <CA+55aFwsjHPe4CF009p_L6PyYdP=F2bzi9-Wm5T+O6XPOCS6fg@mail.gmail.com>
Hi Davidlohr,
On 2014/3/4 11:26, Linus Torvalds wrote:
> On Mon, Mar 3, 2014 at 7:13 PM, Davidlohr Bueso <davidlohr@hp.com> wrote:
>>
>> Yes, I shortly realized that was silly... but I can say for sure it can
>> happen and a quick qemu run confirms it. So I see your point as to
>> asking why we need it, so now I'm looking for an explanation in the
>> code.
>
> We definitely *do* have users.
>
> One example would be ptrace -> access_process_vm -> __access_remote_vm
> -> get_user_pages() -> find_extend_vma() -> find_vma_prev -> find_vma.
>
I raw this oops on 3.14.0-rc5-next-20140307, which is possible caused by
your patch? Don't know how it was triggered.
[ 6072.026715] BUG: unable to handle kernel NULL pointer dereference at 00000000000007f8
[ 6072.026729] IP: [<ffffffff811a0189>] follow_page_mask+0x69/0x620
[ 6072.026742] PGD c1975f067 PUD c19479067 PMD 0
[ 6072.026749] Oops: 0000 [#1] SMP
[ 6072.026852] CPU: 2 PID: 13445 Comm: ps Not tainted 3.14.0-rc5-next-20140307-0.1-default+ #4
[ 6072.026863] Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA , BIO
S CTSAV036 04/27/2011
[ 6072.026872] task: ffff88061d8848a0 ti: ffff880618854000 task.ti: ffff880618854000
[ 6072.026880] RIP: 0010:[<ffffffff811a0189>] [<ffffffff811a0189>] follow_page_mask+0x69/0x620
[ 6072.026889] RSP: 0018:ffff880618855c18 EFLAGS: 00010206
[ 6072.026895] RAX: 00000000000000ff RBX: ffffffffffffffea RCX: ffff880618855d0c
[ 6072.026902] RDX: 0000000000000000 RSI: 00007fff0a474cc7 RDI: ffff88061aef8f00
[ 6072.026909] RBP: ffff880618855c88 R08: 0000000000000002 R09: 0000000000000000
[ 6072.026916] R10: 0000000000000000 R11: 0000000000003485 R12: 00007fff0a474cc7
[ 6072.026924] R13: 0000000000000016 R14: ffff88061aef8f00 R15: ffff880c1c842508
[ 6072.026932] FS: 00007f4687701700(0000) GS:ffff880c26a00000(0000) knlGS:0000000000000000
[ 6072.026940] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 6072.026947] CR2: 00000000000007f8 CR3: 0000000c184ee000 CR4: 00000000000007e0
[ 6072.026955] Stack:
[ 6072.026959] ffff880618855c48 ffff880618855d0c 0000000018855c58 0000000000000246
[ 6072.026969] 0000000000000000 0000000000000752 ffffffff817c975c 0000000000000000
[ 6072.026980] ffff880618855c88 0000000000000016 ffff880c1c842508 ffff88061d8848a0
[ 6072.026989] Call Trace:
[ 6072.026998] [<ffffffff811a4b14>] __get_user_pages+0x204/0x5a0
[ 6072.027007] [<ffffffff811a4f62>] get_user_pages+0x52/0x60
[ 6072.027015] [<ffffffff811a5088>] __access_remote_vm+0x118/0x1f0
[ 6072.027023] [<ffffffff811a51bb>] access_process_vm+0x5b/0x80
[ 6072.027033] [<ffffffff812675a7>] proc_pid_cmdline+0x77/0x120
[ 6072.027041] [<ffffffff81267da2>] proc_info_read+0xa2/0xe0
[ 6072.027050] [<ffffffff811f439d>] vfs_read+0xad/0x1a0
[ 6072.027057] [<ffffffff811f45b5>] SyS_read+0x65/0xb0
[ 6072.027066] [<ffffffff8159ba12>] system_call_fastpath+0x16/0x1b
[ 6072.027072] Code: f4 4c 89 f7 89 45 a4 e8 36 0e eb ff 48 3d 00 f0 ff ff 48 89 c3 0f 86 d7 00 00 00 4c 89 e0
49 8b 56 40 48 c1 e8 27 25 ff 01 00 00 <48> 8b 0c c2 48 85 c9 75 3e 41 83 e5 08 74 1b 49 8b 87 90 00 00
[ 6072.027134] RIP [<ffffffff811a0189>] follow_page_mask+0x69/0x620
[ 6072.027142] RSP <ffff880618855c18>
[ 6072.027146] CR2: 00000000000007f8
[ 6072.134516] ---[ end trace 8d006e01f05d1ba8 ]---
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WARNING: multiple messages have this Message-ID (diff)
From: Li Zefan <lizefan@huawei.com>
To: Davidlohr Bueso <davidlohr@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Michel Lespinasse <walken@google.com>,
Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
"Norton, Scott J" <scott.norton@hp.com>,
linux-mm <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4] mm: per-thread vma caching
Date: Fri, 14 Mar 2014 11:05:51 +0800 [thread overview]
Message-ID: <5322720F.1030706@huawei.com> (raw)
In-Reply-To: <CA+55aFwsjHPe4CF009p_L6PyYdP=F2bzi9-Wm5T+O6XPOCS6fg@mail.gmail.com>
Hi Davidlohr,
On 2014/3/4 11:26, Linus Torvalds wrote:
> On Mon, Mar 3, 2014 at 7:13 PM, Davidlohr Bueso <davidlohr@hp.com> wrote:
>>
>> Yes, I shortly realized that was silly... but I can say for sure it can
>> happen and a quick qemu run confirms it. So I see your point as to
>> asking why we need it, so now I'm looking for an explanation in the
>> code.
>
> We definitely *do* have users.
>
> One example would be ptrace -> access_process_vm -> __access_remote_vm
> -> get_user_pages() -> find_extend_vma() -> find_vma_prev -> find_vma.
>
I raw this oops on 3.14.0-rc5-next-20140307, which is possible caused by
your patch? Don't know how it was triggered.
[ 6072.026715] BUG: unable to handle kernel NULL pointer dereference at 00000000000007f8
[ 6072.026729] IP: [<ffffffff811a0189>] follow_page_mask+0x69/0x620
[ 6072.026742] PGD c1975f067 PUD c19479067 PMD 0
[ 6072.026749] Oops: 0000 [#1] SMP
[ 6072.026852] CPU: 2 PID: 13445 Comm: ps Not tainted 3.14.0-rc5-next-20140307-0.1-default+ #4
[ 6072.026863] Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA , BIO
S CTSAV036 04/27/2011
[ 6072.026872] task: ffff88061d8848a0 ti: ffff880618854000 task.ti: ffff880618854000
[ 6072.026880] RIP: 0010:[<ffffffff811a0189>] [<ffffffff811a0189>] follow_page_mask+0x69/0x620
[ 6072.026889] RSP: 0018:ffff880618855c18 EFLAGS: 00010206
[ 6072.026895] RAX: 00000000000000ff RBX: ffffffffffffffea RCX: ffff880618855d0c
[ 6072.026902] RDX: 0000000000000000 RSI: 00007fff0a474cc7 RDI: ffff88061aef8f00
[ 6072.026909] RBP: ffff880618855c88 R08: 0000000000000002 R09: 0000000000000000
[ 6072.026916] R10: 0000000000000000 R11: 0000000000003485 R12: 00007fff0a474cc7
[ 6072.026924] R13: 0000000000000016 R14: ffff88061aef8f00 R15: ffff880c1c842508
[ 6072.026932] FS: 00007f4687701700(0000) GS:ffff880c26a00000(0000) knlGS:0000000000000000
[ 6072.026940] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 6072.026947] CR2: 00000000000007f8 CR3: 0000000c184ee000 CR4: 00000000000007e0
[ 6072.026955] Stack:
[ 6072.026959] ffff880618855c48 ffff880618855d0c 0000000018855c58 0000000000000246
[ 6072.026969] 0000000000000000 0000000000000752 ffffffff817c975c 0000000000000000
[ 6072.026980] ffff880618855c88 0000000000000016 ffff880c1c842508 ffff88061d8848a0
[ 6072.026989] Call Trace:
[ 6072.026998] [<ffffffff811a4b14>] __get_user_pages+0x204/0x5a0
[ 6072.027007] [<ffffffff811a4f62>] get_user_pages+0x52/0x60
[ 6072.027015] [<ffffffff811a5088>] __access_remote_vm+0x118/0x1f0
[ 6072.027023] [<ffffffff811a51bb>] access_process_vm+0x5b/0x80
[ 6072.027033] [<ffffffff812675a7>] proc_pid_cmdline+0x77/0x120
[ 6072.027041] [<ffffffff81267da2>] proc_info_read+0xa2/0xe0
[ 6072.027050] [<ffffffff811f439d>] vfs_read+0xad/0x1a0
[ 6072.027057] [<ffffffff811f45b5>] SyS_read+0x65/0xb0
[ 6072.027066] [<ffffffff8159ba12>] system_call_fastpath+0x16/0x1b
[ 6072.027072] Code: f4 4c 89 f7 89 45 a4 e8 36 0e eb ff 48 3d 00 f0 ff ff 48 89 c3 0f 86 d7 00 00 00 4c 89 e0
49 8b 56 40 48 c1 e8 27 25 ff 01 00 00 <48> 8b 0c c2 48 85 c9 75 3e 41 83 e5 08 74 1b 49 8b 87 90 00 00
[ 6072.027134] RIP [<ffffffff811a0189>] follow_page_mask+0x69/0x620
[ 6072.027142] RSP <ffff880618855c18>
[ 6072.027146] CR2: 00000000000007f8
[ 6072.134516] ---[ end trace 8d006e01f05d1ba8 ]---
next prev parent reply other threads:[~2014-03-14 3:06 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 21:48 [PATCH v4] mm: per-thread vma caching Davidlohr Bueso
2014-02-27 21:48 ` Davidlohr Bueso
2014-02-28 4:39 ` Davidlohr Bueso
2014-02-28 4:39 ` Davidlohr Bueso
2014-03-04 0:00 ` Andrew Morton
2014-03-04 0:18 ` Davidlohr Bueso
2014-03-04 0:18 ` Davidlohr Bueso
2014-03-04 0:40 ` Andrew Morton
2014-03-04 0:59 ` Davidlohr Bueso
2014-03-04 0:59 ` Davidlohr Bueso
2014-03-04 1:23 ` Andrew Morton
2014-03-04 2:42 ` Davidlohr Bueso
2014-03-04 2:42 ` Davidlohr Bueso
2014-03-04 3:12 ` Andrew Morton
2014-03-04 3:13 ` Davidlohr Bueso
2014-03-04 3:13 ` Davidlohr Bueso
2014-03-04 3:26 ` Andrew Morton
2014-03-04 3:26 ` Linus Torvalds
2014-03-04 3:26 ` Linus Torvalds
2014-03-04 5:32 ` Davidlohr Bueso
2014-03-04 5:32 ` Davidlohr Bueso
2014-03-14 3:05 ` Li Zefan [this message]
2014-03-14 3:05 ` Li Zefan
2014-03-14 4:43 ` Andrew Morton
2014-03-14 4:43 ` Andrew Morton
2014-03-06 22:56 ` Andrew Morton
2014-03-06 22:56 ` Andrew Morton
[not found] ` <20140308184040.GA29602@redhat.com>
[not found] ` <CA+55aFw88xiY+o5FE6VtHNkpUZDK3FPt31oCpNsgn1BH7wAPZw@mail.gmail.com>
2014-03-08 19:57 ` Oleg Nesterov
[not found] ` <20140308194405.GA32403@redhat.com>
2014-03-08 20:02 ` Linus Torvalds
2014-03-09 3:22 ` Davidlohr Bueso
2014-03-09 12:57 ` Oleg Nesterov
2014-03-09 15:57 ` Linus Torvalds
2014-03-09 17:09 ` Oleg Nesterov
2014-03-09 17:16 ` Linus Torvalds
2014-03-10 19:56 ` [PATCH -next] mm,vmacache: also flush cache for VM_CLONE Davidlohr Bueso
2014-03-13 14:59 ` Oleg Nesterov
2014-03-13 15:32 ` Oleg Nesterov
2014-03-13 19:04 ` Davidlohr Bueso
[not found] ` <CA+55aFyNd7L+G3hFauJPxUOengK-_o2G-SFmVooPZ-sE6xBj=g@mail.gmail.com>
2014-03-13 16:36 ` Oleg Nesterov
2014-03-13 18:27 ` async_pf.c && use_mm() (Was: mm,vmacache: also flush cache for VM_CLONE) Oleg Nesterov
[not found] ` <CA+55aFwqTbsYCyPf6_i6RmBkPHpEhJjiRfZm6_1_yPa_kUkYiQ@mail.gmail.com>
2014-03-13 21:44 ` Linus Torvalds
2014-03-14 18:23 ` Oleg Nesterov
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