From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
To: Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sasha.levin@oracle.com>,
Michel Lespinasse <walken@google.com>,
Bob Liu <bob.liu@oracle.com>,
npiggin@suse.de, kosaki.motohiro@jp.fujitsu.com, riel@redhat.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/mlock: fix BUG_ON unlocked page for nolinear VMAs
Date: Wed, 18 Dec 2013 17:01:31 +0800 [thread overview]
Message-ID: <52b1647f.c8da420a.1e7a.ffffbcb4SMTPIN_ADDED_BROKEN@mx.google.com> (raw)
In-Reply-To: <52B162B8.6090507@suse.cz>
Hi Vlastimil,
On Wed, Dec 18, 2013 at 09:54:16AM +0100, Vlastimil Babka wrote:
>On 12/17/2013 09:05 AM, Wanpeng Li wrote:
>>objrmap doesn't work for nonlinear VMAs because the assumption that offset-into-file
>>correlates with offset-into-virtual-addresses does not hold. Hence what
>>try_to_unmap_cluster does is a mini "virtual scan" of each nonlinear VMA which maps
>>the file to which the target page belongs. If vma locked, mlock the pages in the
>>cluster, rather than unmapping them. However, not all pages are guarantee page
>>locked instead of the check page. This patch fix the BUG by just confirm check page
>>hold page lock instead of all pages in the virtual scan window against nolinear VMAs.
>
>This may fix the symptom, but I don't understand from the description
>why in this case is it ok not to have page locked for
>mlock_vma_page(), while in the other cases it's not ok.
>
Here is a latest version of the bugfix patch.
http://marc.info/?l=linux-mm&m=138733994417230&w=2
Regards,
Wanpeng Li
>>[ 253.869145] kernel BUG at mm/mlock.c:82!
>>[ 253.869549] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>>[ 253.870098] Dumping ftrace buffer:
>>[ 253.870098] (ftrace buffer empty)
>>[ 253.870098] Modules linked in:
>>[ 253.870098] CPU: 10 PID: 9162 Comm: trinity-child75 Tainted: G W 3.13.0-rc4-next-20131216-sasha-00011-g5f105ec-dirty #4137
>>[ 253.873310] task: ffff8800c98cb000 ti: ffff8804d34e8000 task.ti: ffff8804d34e8000
>>[ 253.873310] RIP: 0010:[<ffffffff81281f28>] [<ffffffff81281f28>] mlock_vma_page+0x18/0xc0
>>[ 253.873310] RSP: 0000:ffff8804d34e99e8 EFLAGS: 00010246
>>[ 253.873310] RAX: 006fffff8038002c RBX: ffffea00474944c0 RCX: ffff880807636000
>>[ 253.873310] RDX: ffffea0000000000 RSI: 00007f17a9bca000 RDI: ffffea00474944c0
>>[ 253.873310] RBP: ffff8804d34e99f8 R08: ffff880807020000 R09: 0000000000000000
>>[ 253.873310] R10: 0000000000000001 R11: 0000000000002000 R12: 00007f17a9bca000
>>[ 253.873310] R13: ffffea00474944c0 R14: 00007f17a9be0000 R15: ffff880807020000
>>[ 253.873310] FS: 00007f17aa31a700(0000) GS:ffff8801c9c00000(0000) knlGS:0000000000000000
>>[ 253.873310] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>>[ 253.873310] CR2: 00007f17a94fa000 CR3: 00000004d3b02000 CR4: 00000000000006e0
>>[ 253.873310] DR0: 00007f17a74ca000 DR1: 0000000000000000 DR2: 0000000000000000
>>[ 253.873310] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
>>[ 253.873310] Stack:
>>[ 253.873310] 0000000b3de28067 ffff880b3de28e50 ffff8804d34e9aa8 ffffffff8128bc31
>>[ 253.873310] 0000000000000301 ffffea0011850220 ffff8809a4039000 ffffea0011850238
>>[ 253.873310] ffff8804d34e9aa8 ffff880807636060 0000000000000001 ffff880807636348
>>[ 253.873310] Call Trace:
>>[ 253.873310] [<ffffffff8128bc31>] try_to_unmap_cluster+0x1c1/0x340
>>[ 253.873310] [<ffffffff8128c60a>] try_to_unmap_file+0x20a/0x2e0
>>[ 253.873310] [<ffffffff8128c7b3>] try_to_unmap+0x73/0x90
>>[ 253.873310] [<ffffffff812b526d>] __unmap_and_move+0x18d/0x250
>>[ 253.873310] [<ffffffff812b53e9>] unmap_and_move+0xb9/0x180
>>[ 253.873310] [<ffffffff812b559b>] migrate_pages+0xeb/0x2f0
>>[ 253.873310] [<ffffffff812a0660>] ? queue_pages_pte_range+0x1a0/0x1a0
>>[ 253.873310] [<ffffffff812a193c>] migrate_to_node+0x9c/0xc0
>>[ 253.873310] [<ffffffff812a30b8>] do_migrate_pages+0x1b8/0x240
>>[ 253.873310] [<ffffffff812a3456>] SYSC_migrate_pages+0x316/0x380
>>[ 253.873310] [<ffffffff812a31ec>] ? SYSC_migrate_pages+0xac/0x380
>>[ 253.873310] [<ffffffff811763c6>] ? vtime_account_user+0x96/0xb0
>>[ 253.873310] [<ffffffff812a34ce>] SyS_migrate_pages+0xe/0x10
>>[ 253.873310] [<ffffffff843c4990>] tracesys+0xdd/0xe2
>>[ 253.873310] Code: 0f 1f 00 65 48 ff 04 25 10 25 1d 00 48 83 c4 08
>>5b c9 c3 55 48 89 e5 53 48 83 ec 08 66 66 66 66 90 48 8b 07 48 89 fb
>>a8 01 75 10 <0f> 0b 66 0f 1f 44 00 00 eb fe 66 0f 1f 44 00 00 f0 0f ba
>>2f 15
>>[ 253.873310] RIP [<ffffffff81281f28>] mlock_vma_page+0x18/0xc0
>>[ 253.873310] RSP <ffff8804d34e99e8>
>>[ 253.904194] ---[ end trace be59c4a7f8edab3f ]---
>>
>>Reported-by: Sasha Levin <sasha.levin@oracle.com>
>>Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>>---
>> mm/huge_memory.c | 2 +-
>> mm/internal.h | 4 ++--
>> mm/ksm.c | 2 +-
>> mm/memory.c | 2 +-
>> mm/mlock.c | 5 +++--
>> mm/rmap.c | 4 ++--
>> 6 files changed, 10 insertions(+), 9 deletions(-)
>>
>>diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>>index 33a5dc4..7a15b04 100644
>>--- a/mm/huge_memory.c
>>+++ b/mm/huge_memory.c
>>@@ -1264,7 +1264,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
>> if (page->mapping && trylock_page(page)) {
>> lru_add_drain();
>> if (page->mapping)
>>- mlock_vma_page(page);
>>+ mlock_vma_page(page, true);
>> unlock_page(page);
>> }
>> }
>>diff --git a/mm/internal.h b/mm/internal.h
>>index a85a3ab..4ea2d4e 100644
>>--- a/mm/internal.h
>>+++ b/mm/internal.h
>>@@ -192,7 +192,7 @@ static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
>> /*
>> * must be called with vma's mmap_sem held for read or write, and page locked.
>> */
>>-extern void mlock_vma_page(struct page *page);
>>+extern void mlock_vma_page(struct page *page, bool check_page);
>> extern unsigned int munlock_vma_page(struct page *page);
>>
>> /*
>>@@ -236,7 +236,7 @@ static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
>> return 0;
>> }
>> static inline void clear_page_mlock(struct page *page) { }
>>-static inline void mlock_vma_page(struct page *page) { }
>>+static inline void mlock_vma_page(struct page *page, bool check_page) { }
>> static inline void mlock_migrate_page(struct page *new, struct page *old) { }
>>
>> #endif /* !CONFIG_MMU */
>>diff --git a/mm/ksm.c b/mm/ksm.c
>>index 175fff7..ec36f04 100644
>>--- a/mm/ksm.c
>>+++ b/mm/ksm.c
>>@@ -1064,7 +1064,7 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
>> if (!PageMlocked(kpage)) {
>> unlock_page(page);
>> lock_page(kpage);
>>- mlock_vma_page(kpage);
>>+ mlock_vma_page(kpage, true);
>> page = kpage; /* for final unlock */
>> }
>> }
>>diff --git a/mm/memory.c b/mm/memory.c
>>index cf6098c..a41df6a 100644
>>--- a/mm/memory.c
>>+++ b/mm/memory.c
>>@@ -1602,7 +1602,7 @@ split_fallthrough:
>> * know the page is still mapped, we don't even
>> * need to check for file-cache page truncation.
>> */
>>- mlock_vma_page(page);
>>+ mlock_vma_page(page, true);
>> unlock_page(page);
>> }
>> }
>>diff --git a/mm/mlock.c b/mm/mlock.c
>>index d480cd6..c395ec5 100644
>>--- a/mm/mlock.c
>>+++ b/mm/mlock.c
>>@@ -77,9 +77,10 @@ void clear_page_mlock(struct page *page)
>> * Mark page as mlocked if not already.
>> * If page on LRU, isolate and putback to move to unevictable list.
>> */
>>-void mlock_vma_page(struct page *page)
>>+void mlock_vma_page(struct page *page, bool check_page)
>> {
>>- BUG_ON(!PageLocked(page));
>>+ if (check_page)
>>+ BUG_ON(!PageLocked(page));
>>
>> if (!TestSetPageMlocked(page)) {
>> mod_zone_page_state(page_zone(page), NR_MLOCK,
>>diff --git a/mm/rmap.c b/mm/rmap.c
>>index 55c8b8d..79d456f 100644
>>--- a/mm/rmap.c
>>+++ b/mm/rmap.c
>>@@ -1297,7 +1297,7 @@ out_mlock:
>> */
>> if (down_read_trylock(&vma->vm_mm->mmap_sem)) {
>> if (vma->vm_flags & VM_LOCKED) {
>>- mlock_vma_page(page);
>>+ mlock_vma_page(page, true);
>> ret = SWAP_MLOCK;
>> }
>> up_read(&vma->vm_mm->mmap_sem);
>>@@ -1385,7 +1385,7 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
>> BUG_ON(!page || PageAnon(page));
>>
>> if (locked_vma) {
>>- mlock_vma_page(page); /* no-op if already mlocked */
>>+ mlock_vma_page(page, page == check_page); /* no-op if already mlocked */
>> if (page == check_page)
>> ret = SWAP_MLOCK;
>> continue; /* don't unmap */
>>
--
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prev parent reply other threads:[~2013-12-18 9:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 8:05 Wanpeng Li
2013-12-18 3:14 ` Wanpeng Li
2013-12-18 3:16 ` Wanpeng Li
2013-12-18 3:23 ` Wanpeng Li
[not found] ` <20131218032329.GA6044@hacker.(null)>
2013-12-18 3:32 ` Sasha Levin
2013-12-18 4:12 ` Wanpeng Li
2013-12-18 9:11 ` Vlastimil Babka
2013-12-18 9:23 ` Wanpeng Li
[not found] ` <52b1699f.87293c0a.75d1.34d3SMTPIN_ADDED_BROKEN@mx.google.com>
2013-12-18 21:43 ` Andrew Morton
2014-01-03 20:17 ` Sasha Levin
2014-01-03 20:52 ` Linus Torvalds
2014-01-03 23:36 ` Vlastimil Babka
2014-01-03 23:56 ` Andrew Morton
2014-01-04 3:03 ` Sasha Levin
2014-01-04 0:18 ` Linus Torvalds
2014-01-04 8:09 ` Vlastimil Babka
2014-01-05 0:27 ` Wanpeng Li
2014-01-06 16:47 ` Motohiro Kosaki
2014-01-06 22:01 ` KOSAKI Motohiro
2014-01-07 5:27 ` Wanpeng Li
2014-01-07 15:01 ` Vlastimil Babka
2014-01-08 1:06 ` Bob Liu
2014-01-08 2:44 ` Linus Torvalds
2014-01-10 17:48 ` Motohiro Kosaki
2014-01-13 14:03 ` Vlastimil Babka
2014-01-14 11:05 ` Vlastimil Babka
2014-01-04 3:31 ` Bob Liu
2013-12-18 8:54 ` Vlastimil Babka
2013-12-18 9:01 ` Wanpeng Li [this message]
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