On 06/18/2015 06:32 PM, Jovi Zhangwei wrote: > From: Mel Gorman <mgorman@xxxxxxx> > > commit 8e76d4eecf7afeec9328e21cd5880e281838d0d6 upstream. > > 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@xxxxxxx> > [jovi: Backported to 3.18: adjust context] > Signed-off-by: Jovi Zhangwei <jovi@xxxxxxxxxxxxxx> > Reported-by: Jovi Zhangwei <jovi@xxxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxx> > Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Hi Jovi, Just for the sake of following the same rules as upstream, can you resend it with the correct SoB? Yours should be at the bottom rather than inserted at the middle. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html