From: Jovi Zhangwei <jovi.zhangwei@gmail.com>
To: inux-kernel@vger.kernel.org, mgorman@suse.de,
Sasha Levin <sasha.levin@oracle.com>,
n-horiguchi@ah.jp.nec.com,
Andrew Morton <akpm@linux-foundation.org>,
hughd@google.com, linux-mm@kvack.org, vbabka@suse.cz,
rientjes@google.com
Subject: [PATCH] mm/migrate: Avoid migrate mmaped compound pages
Date: Wed, 27 May 2015 16:52:31 -0700 [thread overview]
Message-ID: <CAGdX0WH9YbrZ0xN0HKwBmRJ3LNt_JPA4nmDLNV9CypwQRKQpQw@mail.gmail.com> (raw)
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Below kernel vm bug can be triggered by tcpdump which mmaped a lot of pages
with GFP_COMP flag.
[Mon May 25 05:29:33 2015] page:ffffea0015414000 count:66 mapcount:1
mapping: (null) index:0x0
[Mon May 25 05:29:33 2015] flags: 0x20047580004000(head)
[Mon May 25 05:29:33 2015] page dumped because:
VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page))
[Mon May 25 05:29:33 2015] ------------[ cut here ]------------
[Mon May 25 05:29:33 2015] kernel BUG at mm/migrate.c:1661!
[Mon May 25 05:29:33 2015] invalid opcode: 0000 [#1] SMP
The fix is simply disallow migrate mmaped compound pages, return 0 instead
of
report vm bug.
Signed-off-by: Jovi Zhangwei <jovi.zhangwei@gmail.com>
---
mm/migrate.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index f53838f..839adef 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1606,7 +1606,8 @@ static int numamigrate_isolate_page(pg_data_t *pgdat,
struct page *page)
{
int page_lru;
- VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page), page);
+ if (compound_order(page) && !PageTransHuge(page))
+ return 0;
/* Avoid migrating to a node that is nearly full */
if (!migrate_balanced_pgdat(pgdat, 1UL << compound_order(page)))
--
1.9.1
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next reply other threads:[~2015-05-27 23:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-27 23:52 Jovi Zhangwei [this message]
2015-05-27 23:54 [PATCH] mm/migrate: Avoid migrate mmaped compound pages Jovi Zhangwei
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