Hi all, When I try to run Ubuntu 14.10 guest (the nightly build with the kernel version 3.16.0-12-generic) on hyper-v, occasionally, I get the below panic(see the end of the mail) suddenly. (I suppose it's likely the upstream kernel has the issue too) When the panic happens, I'm running a memory stress program to test the balloon driver drivers/hv/hv_balloon.c, which can hot-add memory to the guest by invoking memory_add_physaddr_to_nid() and add_memory(), if the feature "Dynamic Memory" is enabled. The issue here is: the memory hot-add seems successful, but occasionally the page fault can happen and crash the whole guest. It looks the crash only happens to the guest in the SMP guest case. I never get the crash when the guest is configured with 1 vCPU. Sometimes it's very difficult to reproduce the crash while sometimes it's relatively easy. Can anybody please shed some light? Thanks! -- Dexuan [ 99.211382] BUG: unable to handle kernel paging request at 0000000000c0b608 [ 99.215308] IP: [<ffffffff811d2e9c>] mem_cgroup_page_lruvec+0x2c/0xa0 [ 99.215308] PGD 37544067 PUD 393c2067 PMD 0 [ 99.215308] Oops: 0000 [#1] SMP [ 99.215308] Modules linked in: bnep rfcomm bluetooth 6lowpan_iphc joydev hid_generic crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd hyperv_keyboard hv_balloon hid_hyperv hid serio_raw i2c_piix4 mac_hid parport_pc ppdev lp parport hv_netvsc hv_utils hv_storvsc psmouse hv_vmbus pata_acpi floppy [ 99.215308] CPU: 3 PID: 1919 Comm: stressapptest Not tainted 3.16.0-12-generic #18-Ubuntu [ 99.215308] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 99.215308] task: ffff880034282880 ti: ffff8800415f8000 task.ti: ffff8800415f8000 [ 99.215308] RIP: 0010:[<ffffffff811d2e9c>] [<ffffffff811d2e9c>] mem_cgroup_page_lruvec+0x2c/0xa0 [ 99.215308] RSP: 0000:ffff8800415fbc58 EFLAGS: 00010006 [ 99.215308] RAX: 0000000000c0b600 RBX: ffff88003ffebf80 RCX: ffff88003ffea300 [ 99.215308] RDX: 02ffff00000d0001 RSI: ffff88003ffebf80 RDI: ffffea000302d800 [ 99.215308] RBP: ffff8800415fbc68 R08: 0000000000000008 R09: 0000000000000004 [ 99.215308] R10: 00000000ffffffff R11: ffff880033ffd400 R12: ffffea000302d800 [ 99.215308] R13: ffffea000302d800 R14: ffff88003b4703c0 R15: 0000000000000202 [ 99.215308] FS: 00007fb0075fa700(0000) GS:ffff88003b460000(0000) knlGS:0000000000000000 [ 99.215308] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 99.215308] CR2: 0000000000c0b608 CR3: 00000000389b4000 CR4: 00000000000006e0 [ 99.215308] Stack: [ 99.215308] ffff88003ffebf80 0000000000000002 ffff8800415fbcc0 ffffffff81178604 [ 99.215308] 0000000000000000 ffffffff81177bf0 0000000000000296 ffff8800415fbc90 [ 99.215308] 0000000000000003 000000000004b5d8 00000000000200da ffff880036db6480 [ 99.215308] Call Trace: [ 99.215308] [<ffffffff81178604>] pagevec_lru_move_fn+0xc4/0x130 [ 99.215308] [<ffffffff81177bf0>] ? __activate_page+0x1e0/0x1e0 [ 99.215308] [<ffffffff81178b7e>] lru_add_drain_cpu+0xce/0xe0 [ 99.215308] [<ffffffff81178c96>] lru_add_drain+0x16/0x20 [ 99.215308] [<ffffffff811aa2e6>] swapin_readahead+0x126/0x1a0 [ 99.215308] [<ffffffff81198c17>] handle_mm_fault+0xc87/0xf90 [ 99.215308] [<ffffffff8105ce42>] __do_page_fault+0x1c2/0x580 [ 99.215308] [<ffffffff810a9d18>] ? __enqueue_entity+0x78/0x80 [ 99.215308] [<ffffffff810ae8c4>] ? update_curr+0xf4/0x180 [ 99.215308] [<ffffffff810ab3f8>] ? pick_next_entity+0x88/0x180 [ 99.215308] [<ffffffff810b3b8e>] ? pick_next_task_fair+0x57e/0x8d0 [ 99.215308] [<ffffffff810a84e8>] ? sched_clock_cpu+0x88/0xb0 [ 99.215308] [<ffffffff8105d231>] do_page_fault+0x31/0x70 [ 99.215308] [<ffffffff81782908>] page_fault+0x28/0x30 [ 99.215308] Code: 66 66 66 90 8b 15 15 2a b5 00 55 48 8d 86 48 05 00 00 48 89 e5 41 54 53 85 d2 48 89 f3 75 56 49 89 fc e8 18 44 00 00 49 8b 14 24 <48> 8b 48 08 83 e2 20 75 1b 48 8b 10 83 e2 02 75 13 48 8b 15 54 [ 99.215308] RIP [<ffffffff811d2e9c>] mem_cgroup_page_lruvec+0x2c/0xa0 [ 99.215308] RSP <ffff8800415fbc58> [ 99.215308] CR2: 0000000000c0b608 [ 99.215308] ---[ end trace 24db5f2378e898cb ]--- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href