I could be on a wild goose chase here. But one of the prominent changes between 77 and 78 is the backing_dev_info element of the queue turning into a pointer.
Part of the "bdi" changes in this bit: ++ * UbuntuKVM guest crashed while running I/O stress test with Ubuntu kernel ++ 4.4.0-47-generic (LP: #1659111) I believe from here: https://patchwork.kernel.org/patch/9547199/ For example this: --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2462,7 +2462,7 @@ static int drbd_congested(void *congested_data, int bdi_bits) if (get_ldev(device)) { q = bdev_get_queue(device->ldev->backing_bdev); - r = bdi_congested(&q->backing_dev_info, bdi_bits); + r = bdi_congested(q->backing_dev_info, bdi_bits); put_ldev(device); if (r) reason = 'b'; But if I check the Ubuntu-specific code, that change does not seem to be done everywhere: $ zcat linux_4.4.0-78.99.diff.gz | grep bdi_congested.*backing_dev -B2 | tail -n8 struct request_queue *q = bdev_get_queue(rdev->bdev); - ret |= bdi_congested(&q->backing_dev_info, bits); + ret |= bdi_congested(q->backing_dev_info, bits); -- + struct request_queue *q = bdev_get_queue(rs->dev[p].dev->bdev); + + r |= bdi_congested(&q->backing_dev_info, bdi_bits); Extracting only the "new" files, I find it here indeed: $ mkdir foo; cd foo $ patch -tp1 < ../linux_4.4.0-78.99.diff.gz $ find . -name '*.c' | xargs grep -B2 bdi_congested.*backing_dev_info ./ubuntu/dm-raid4-5/dm-raid4-5.c- struct request_queue *q = bdev_get_queue(rs->dev[p].dev->bdev); ./ubuntu/dm-raid4-5/dm-raid4-5.c- ./ubuntu/dm-raid4-5/dm-raid4-5.c: r |= bdi_congested(&q->backing_dev_info, bdi_bits); This is just an example of course, I believe there could be more "bdi" changes like that one that haven't been made. Correct me if I'm wrong though. I've never done any kernel dev, so I could be way off base here. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1691741 Title: Execute NX-protected page - 4.4.0-78-generic - kernel panic Status in linux package in Ubuntu: Confirmed Bug description: After upgrading from 4.4.0-77 to 4.4.0-78 I started getting kernel panics. The crashes do not happen immediately, but have happened generally after a couple of minutes, sometimes more. After enabling linux-crashdump stuff, I managed to extract this dmesg. [ 995.103846] kernel tried to execute NX-protected page - exploit attempt? (uid: 0) [ 995.104141] BUG: unable to handle kernel paging request at ffff88042a284000 [ 995.104407] IP: [<ffff88042a284000>] 0xffff88042a284000 [ 995.104594] PGD 43f20b067 PUD 43f20e067 PMD 42a3da063 PTE 800000042a284163 [ 995.104946] Oops: 0011 [#1] SMP [ 995.105143] Modules linked in: zfs(PO) zunicode(PO) zcommon(PO) znvpair(PO) spl(O) zavl(PO) ppdev input_leds shpchp serio_raw i2c_piix4 mac_hid parport_pc parport 8250_fintek autofs4 ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm psmouse floppy pata_acpi [ 995.107081] CPU: 1 PID: 0 Comm: swapper/1 Tainted: P O 4.4.0-78-generic #99-Ubuntu [ 995.107299] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 [ 995.107573] task: ffff88042a278000 ti: ffff88042a280000 task.ti: ffff88042a280000 [ 995.108070] RIP: 0010:[<ffff88042a284000>] [<ffff88042a284000>] 0xffff88042a284000 [ 995.108637] RSP: 0018:ffff88042a283ed0 EFLAGS: 00010082 [ 995.109116] RAX: 0000000000000001 RBX: 000000e797438af0 RCX: 0000000000000000 [ 995.109638] RDX: 0000000000000001 RSI: 0000000000000083 RDI: 0000000000000083 [ 995.110143] RBP: ffffffff81f38d40 R08: 000000000000000a R09: 0000000000000000 [ 995.110665] R10: 000000010002a665 R11: 0000000000004c00 R12: ffff88042a283ed0 [ 995.111182] R13: ffffffff810ff75e R14: 0000000000000000 R15: ffff88042a280000 [ 995.111733] FS: 0000000000000000(0000) GS:ffff88043fc80000(0000) knlGS:0000000000000000 [ 995.112486] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 995.112978] CR2: ffff88042a284000 CR3: 000000043d246000 CR4: 00000000000006e0 [ 995.113497] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 995.114085] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 995.114612] Stack: [ 995.114965] ffff88042a283f28 ffffffff810c4736 ffff88042a280000 ffff88042a284000 [ 995.116204] ee041b0196f77cc4 a1abbcd2b8b123ce 0000000000000000 0000000000000000 [ 995.117389] 0000000000000000 0000000000000000 0000000000000000 ffff88042a283f48 [ 995.118425] Call Trace: [ 995.118811] [<ffffffff810c4736>] ? cpu_startup_entry+0x176/0x350 [ 995.119293] [<ffffffff810517c4>] ? start_secondary+0x154/0x190 [ 995.119775] Code: ff ff ff 00 00 00 00 00 00 00 00 10 00 00 00 00 00 00 00 02 02 00 00 00 00 00 00 58 3f 28 2a 04 88 ff ff 18 00 00 00 00 00 00 00 <c0> 8c 27 2a 04 88 ff ff 00 00 00 00 00 00 00 00 02 00 00 00 00 [ 995.125554] RIP [<ffff88042a284000>] 0xffff88042a284000 [ 995.126088] RSP <ffff88042a283ed0> [ 995.126453] CR2: ffff88042a284000 I've upgraded other machines as well, and only this particular VM shows this behaviour. I have a crash dump, but I haven't looked into the contents yet. Getting the dmesg was already a pain in the behind. The VM this happens on is: - a KVM guest - x86_64, 4 cores - 16gb ram lsb_release: Distributor ID: Ubuntu Description: Ubuntu 16.04.2 LTS Release: 16.04 Codename: xenial lspci says: 00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02) 00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II] 00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II] 00:01.2 USB controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01) 00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03) 00:02.0 VGA compatible controller: VMware SVGA II Adapter 00:03.0 Unclassified device [00ff]: Red Hat, Inc Virtio memory balloon 00:0a.0 SCSI storage controller: Red Hat, Inc Virtio block device 00:0b.0 SCSI storage controller: Red Hat, Inc Virtio block device 00:12.0 Ethernet controller: Red Hat, Inc Virtio network device 00:1e.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge 00:1f.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge Let me know if there are other helpful details I can provide. If I find out more, I'll update this ticket. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1691741/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
