Hi Maurizio, FYI, we noticed the below changes on commit 3979ef4dcf3d1de55a560a3a4016c30a835df44d ("bio-modify-__bio_add_page-to-accept-pages-that-dont-start-a-new-segment-v3") +------------------------------------------+------------+------------+ | | fceb38f36f | 3979ef4dcf | +------------------------------------------+------------+------------+ | boot_successes | 25 | 10 | | boot_failures | 0 | 6 | | kernel_BUG_at_drivers/block/virtio_blk.c | 0 | 6 | | invalid_opcode | 0 | 6 | | RIP:virtio_queue_rq | 0 | 6 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 6 | | backtrace:blk_mq_work_fn | 0 | 6 | | kernel_BUG_at_arch/x86/mm/pageattr.c | 0 | 3 | | RIP:change_page_attr_set_clr | 0 | 3 | +------------------------------------------+------------+------------+ [ 725.907416] EXT4-fs (vda): mounted filesystem with ordered data mode. Opts: acl,user_xattr [ 728.625269] EXT4-fs (vdd): mounted filesystem without journal. Opts: acl,user_xattr,noload [ 729.053064] ------------[ cut here ]------------ [ 729.053181] kernel BUG at drivers/block/virtio_blk.c:166! [ 729.053181] invalid opcode: 0000 [#1] SMP [ 729.053181] Modules linked in: ext4 mbcache jbd2 dm_mod fuse sg sr_mod cdrom ata_generic pata_acpi floppy parport_pc snd_pcm parport snd_timer cirrus syscopyarea sysfillrect snd sysimgblt ttm drm_kms_helper soundcore drm pcspkr ata_piix libata i2c_piix4 [ 729.053181] CPU: 0 PID: 1645 Comm: kworker/0:1H Not tainted 3.15.0-rc5-next-20140521 #1 [ 729.053181] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 729.053181] task: ffff880119add880 ti: ffff880103264000 task.ti: ffff880103264000 [ 729.053181] RIP: 0010:[] [] virtio_queue_rq+0x217/0x220 [ 729.053181] RSP: 0018:ffff880103265d58 EFLAGS: 00010202 [ 729.053181] RAX: 0000000000000081 RBX: ffff880116164900 RCX: dead000000200200 [ 729.053181] RDX: 0000000000007530 RSI: ffff8800a16c4800 RDI: ffff8800a1693400 [ 729.053181] RBP: ffff880103265d98 R08: ffff8800a16c4800 R09: ffff880103265dc8 [ 729.053181] R10: dffd025bd0493448 R11: 0000000000001000 R12: ffff8800a16c4800 [ 729.053181] R13: ffff880103265dc8 R14: 0000000110000001 R15: ffff8800a1693400 [ 729.053181] FS: 0000000000000000(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000 [ 729.053181] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 729.053181] CR2: 000000000225a000 CR3: 000000008fc00000 CR4: 00000000000006f0 [ 729.053181] Stack: [ 729.053181] ffff880103265d80 ffffffff810a7295 ffff8800a16c4970 ffff8800a1559680 [ 729.053181] ffff8800a1693400 ffff880103265dc8 ffff8800a16c4800 ffff8800a14e1280 [ 729.053181] ffff880103265e00 ffffffff812e0335 ffff8800a1693408 ffff8800a1559680 [ 729.053181] Call Trace: [ 729.053181] [] ? set_next_entity+0x95/0xb0 [ 729.053181] [] __blk_mq_run_hw_queue+0x245/0x410 [ 729.053181] [] blk_mq_run_work_fn+0x12/0x20 [ 729.053181] [] process_one_work+0x183/0x490 [ 729.053181] [] worker_thread+0x11d/0x5c0 [ 729.053181] [] ? rescuer_thread+0x3a0/0x3a0 [ 729.053181] [] kthread+0xd2/0xf0 [ 729.053181] [] ? kthread_create_on_node+0x180/0x180 [ 729.053181] [] ret_from_fork+0x7c/0xb0 [ 729.053181] [] ? kthread_create_on_node+0x180/0x180 [ 729.053181] Code: 00 00 00 00 0f b7 86 f4 00 00 00 c7 86 78 01 00 00 02 00 00 00 48 c7 86 80 01 00 00 00 00 00 00 89 86 7c 01 00 00 e9 6f fe ff ff <0f> 0b 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 57 41 [ 729.053181] RIP [] virtio_queue_rq+0x217/0x220 [ 729.053181] RSP [ 729.053181] ------------[ cut here ]------------ Full dmesg and reproduce script attached. Thanks, Jet