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| author | Mel Gorman <mgorman@suse.de> | 2015-06-10 20:15:00 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-11 01:43:43 +0200 |
| commit | 8e76d4eecf7afeec9328e21cd5880e281838d0d6 (patch) | |
| tree | 90d2bdbbb5847ae9c25fd0f59d1bc09010b5aea4 | |
| parent | zsmalloc: fix a null pointer dereference in destroy_handle_cache() (diff) | |
| download | linux-8e76d4eecf7afeec9328e21cd5880e281838d0d6.tar.xz linux-8e76d4eecf7afeec9328e21cd5880e281838d0d6.zip | |
sched, numa: do not hint for NUMA balancing on VM_MIXEDMAP mappings
Jovi Zhangwei reported the following problem
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
In this case it was triggered by running tcpdump but it's not necessary
reproducible on all systems.
sudo tcpdump -i bond0.100 'tcp port 4242' -c 100000000000 -w 4242.pcap
Compound pages cannot be migrated and it was not expected that such pages
be marked for NUMA balancing. This did not take into account that drivers
such as net/packet/af_packet.c may insert compound pages into userspace
with vm_insert_page. This patch tells the NUMA balancing protection
scanner to skip all VM_MIXEDMAP mappings which avoids the possibility that
compound pages are marked for migration.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Jovi Zhangwei <jovi@cloudflare.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/sched/fair.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ffeaa4105e48..c2980e8733bc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2181,7 +2181,7 @@ void task_numa_work(struct callback_head *work) } for (; vma; vma = vma->vm_next) { if (!vma_migratable(vma) || !vma_policy_mof(vma) || - is_vm_hugetlb_page(vma)) { + is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) { continue; } |