* [PATCH] mm/migrate: Avoid migrate mmaped compound pages
@ 2015-05-27 23:52 Jovi Zhangwei
0 siblings, 0 replies; 2+ messages in thread
From: Jovi Zhangwei @ 2015-05-27 23:52 UTC (permalink / raw)
To: inux-kernel, mgorman, Sasha Levin, n-horiguchi, Andrew Morton,
hughd, linux-mm, vbabka, rientjes
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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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^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH] mm/migrate: Avoid migrate mmaped compound pages
@ 2015-05-27 23:54 Jovi Zhangwei
0 siblings, 0 replies; 2+ messages in thread
From: Jovi Zhangwei @ 2015-05-27 23:54 UTC (permalink / raw)
To: LKML, mgorman, Sasha Levin, n-horiguchi, Andrew Morton, hughd,
linux-mm, vbabka, rientjes
[-- Attachment #1: Type: text/plain, Size: 1263 bytes --]
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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^ permalink raw reply related [flat|nested] 2+ messages in thread
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