On Tue, Feb 24, 2015 at 3:12 AM, Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote: > On Wed, Feb 04, 2015 at 08:34:04PM +0400, Andrey Korolyov wrote: >> >Hi, >> > >> >I've seen the problem quite a few times. Before spending more time on >> >it, I'd like to have a quick check here to see if anyone ever saw the >> >same problem? Hope it is a relevant question with this mail list. >> > >> > >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.078623] BUG: unable to handle >> >kernel NULL pointer dereference at 0000000000000008 >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.078916] IP: [<ffffffff8118d0fa>] >> >copy_huge_page+0x8a/0x2a0 >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.079128] PGD 0 >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.079198] Oops: 0000 [#1] SMP >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.079319] Modules linked in: >> >ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE >> >iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 >> >xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle xt_tcpudp >> >iptable_filter ip_tables x_tables kvm_intel kvm bridge stp llc ast ttm >> >drm_kms_helper drm sysimgblt sysfillrect syscopyarea lp mei_me ioatdma >> >ext2 parport mei shpchp dcdbas joydev mac_hid lpc_ich acpi_pad wmi >> >hid_generic usbhid hid ixgbe igb dca i2c_algo_bit ahci ptp libahci >> >mdio pps_core >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.081090] CPU: 19 PID: 3494 Comm: >> >qemu-system-x86 Not tainted 3.11.0-15-generic #25~precise1-Ubuntu >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.081424] Hardware name: Dell Inc. >> >PowerEdge C6220 II/09N44V, BIOS 2.0.3 07/03/2013 >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.081705] task: ffff881026750000 >> >ti: ffff881026056000 task.ti: ffff881026056000 >> >Jul 2 11:08:21 arno-3 kernel: [ 2165.081973] RIP: >> >0010:[<ffffffff8118d0fa>] [<ffffffff8118d0fa>] >> >copy_huge_page+0x8a/0x2a0 >> >> >> Hello, >> >> sorry for possible top-posting, the same issue appears on at least >> 3.10 LTS series. The original thread is at >> http://marc.info/?l=kvm&m=14043742300901. > > Andrey, > > I am unable to access the URL above? > >> The necessary components for failure to reappear are a single running >> kvm guest and mounted large thp: hugepagesz=1G (seemingly the same as >> in initial report). With default 2M pages everything is working well, >> the same for 3.18 with 1G THP. Are there any obvious clues for the >> issue? >> >> Thanks! > > Hello, Marcelo, sorry, I`ve missed your reply in time. The working link, for example is http://www.spinics.net/lists/linux-mm/msg75658.html. The reproducer is a very simple, you need 1G THP and mounted hugetlbfs. What is interesting, if guest is backed by THP like '-object memory-backend-file,id=mem,size=1G,mem-path=/hugepages,share=on' the failure is less likely to occur. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
