Hi On Thu, Jun 18, 2015 at 4:52 PM, Sasha Levin <sasha.levin@xxxxxxxxxx> wrote: > > 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. > Sorry for that, already resend. -- 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