Re: [PATCH BUGFIX 1/1] block, bfq: add requeue-request hook

From: Oleksandr Natalenko
Date: Tue Feb 06 2018 - 09:07:27 EST

Hi.

06.02.2018 14:46, Mike Galbraith wrote:
Sorry for the noise, but just to make it clear, are we talking about
"deadline" or "mq-deadline" now?

mq-deadline.

Okay, I've spent a little bit more time on stressing the VM with BFQ + this patch enabled, and managed to get it crashed relatively easy just by traversing through all the files in the /usr and reading them. 3 stacktraces from different boots are below:

===
[ 33.147909] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 33.156874] IP: blk_flush_complete_seq+0x20a/0x300
[ 33.160400] PGD 0 P4D 0
[ 33.162682] Oops: 0002 [#1] PREEMPT SMP PTI
[ 33.166091] Modules linked in: crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc nls_iso8859_1 nls_cp437 aesni_intel vfat aes_x86_64 crypto_simd fat glue_helper cryptd bochs_drm ttm iTCO_wdt drm_kms_helper iTCO_vendor_support ppdev psmouse drm input_leds led_class syscopyarea intel_agp parport_pc joydev parport evdev rtc_cmos mousedev intel_gtt mac_hid i2c_i801 sysfillrect lpc_ich sysimgblt agpgart fb_sys_fops qemu_fw_cfg sch_fq_codel ip_tables x_tables hid_generic usbhid hid xfs libcrc32c crc32c_generic dm_mod raid10 md_mod sr_mod cdrom sd_mod uhci_hcd ahci libahci xhci_pci serio_raw atkbd libata ehci_pci virtio_net libps2 xhci_hcd ehci_hcd crc32c_intel scsi_mod virtio_pci usbcore virtio_ring usb_common virtio i8042 serio
[ 33.226238] CPU: 0 PID: 0 Comm: BFS/0 Not tainted 4.15.0-pf2 #1
[ 33.232823] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 33.245062] RIP: 0010:blk_flush_complete_seq+0x20a/0x300
[ 33.247781] RSP: 0018:ffff88001f803ed0 EFLAGS: 00010086
[ 33.250184] RAX: ffff8800199b5e00 RBX: ffff8800199b5de0 RCX: ffff8800197f72a8
[ 33.253220] RDX: 0000000000000000 RSI: ffff8800199b5e10 RDI: ffff8800197f7200
[ 33.257429] RBP: ffff8800194090a0 R08: ffff8800199b5df0 R09: 0000000000000000
[ 33.260756] R10: ffff88001df2b600 R11: ffff88001f803ce8 R12: 0000000000000000
[ 33.268840] R13: ffff8800199b5e30 R14: 0000000000000046 R15: ffff8800199b5de0
[ 33.272722] FS: 0000000000000000(0000) GS:ffff88001f800000(0000) knlGS:0000000000000000
[ 33.276798] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 33.278981] CR2: 0000000000000000 CR3: 0000000004008003 CR4: 00000000003606f0
[ 33.282078] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 33.285566] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 33.289322] Call Trace:
[ 33.291094] <IRQ>
[ 33.294208] mq_flush_data_end_io+0xb3/0xf0
[ 33.301226] scsi_end_request+0x90/0x1e0 [scsi_mod]
[ 33.303660] scsi_io_completion+0x237/0x650 [scsi_mod]
[ 33.306833] flush_smp_call_function_queue+0x7c/0xf0
[ 33.311369] smp_call_function_single_interrupt+0x32/0xf0
[ 33.314245] call_function_single_interrupt+0xa2/0xb0
[ 33.316755] </IRQ>
[ 33.318365] RIP: 0010:native_safe_halt+0x2/0x10
[ 33.321988] RSP: 0018:ffffffff82003ea0 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff04
[ 33.324995] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 33.334532] RDX: 0000000000000000 RSI: ffffffff81e43850 RDI: ffffffff81e43a9d
[ 33.336643] RBP: ffffffff82128080 R08: 0000000e7441b6ce R09: ffff88001a4c2c00
[ 33.339282] R10: 0000000000000000 R11: ffff88001bceb7f0 R12: ffffffff81ea5c92
[ 33.344597] R13: 0000000000000000 R14: 0000000000000000 R15: 000000001e07cd69
[ 33.346526] default_idle+0x18/0x130
[ 33.347929] do_idle+0x167/0x1d0
[ 33.349201] cpu_startup_entry+0x6f/0x80
[ 33.350553] start_kernel+0x4c2/0x4e2
[ 33.351822] secondary_startup_64+0xa5/0xb0
[ 33.354470] Code: 39 d0 0f 84 8f 00 00 00 48 8b 97 b0 00 00 00 49 c1 e0 04 45 31 e4 48 8b b7 a8 00 00 00 49 01 d8 48 8d 8f a8 00 00 00 48 89 56 08 <48> 89 32 49 8b 50 18 49 89 48 18 48 89 87 a8 00 00 00 48 89 97
[ 33.364997] RIP: blk_flush_complete_seq+0x20a/0x300 RSP: ffff88001f803ed0
[ 33.366759] CR2: 0000000000000000
[ 33.367921] ---[ end trace 5179c1a9cbc4eaa2 ]---
[ 33.369413] Kernel panic - not syncing: Fatal exception in interrupt
[ 33.372089] Kernel Offset: disabled
[ 33.374413] ---[ end Kernel panic - not syncing: Fatal exception in interrupt
===

===
[ 30.937747] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
[ 30.940984] IP: bfq_put_queue+0x10b/0x130
[ 30.941609] PGD 0 P4D 0
[ 30.941976] Oops: 0000 [#1] PREEMPT SMP PTI
[ 30.942560] Modules linked in: crct10dif_pclmul crc32_pclmul ghash_clmulni_intel nls_iso8859_1 bochs_drm pcbc nls_cp437 vfat ttm aesni_intel fat aes_x86_64 crypto_simd glue_helper cryptd drm_kms_helper iTCO_wdt drm ppdev iTCO_vendor_support input_leds psmouse led_class intel_agp parport_pc joydev mousedev intel_gtt syscopyarea parport rtc_cmos evdev sysfillrect sysimgblt agpgart fb_sys_fops i2c_i801 mac_hid qemu_fw_cfg lpc_ich sch_fq_codel ip_tables x_tables xfs libcrc32c crc32c_generic dm_mod raid10 md_mod hid_generic usbhid hid sr_mod cdrom sd_mod uhci_hcd ahci libahci serio_raw virtio_net xhci_pci ehci_pci atkbd libata libps2 xhci_hcd virtio_pci ehci_hcd virtio_ring crc32c_intel scsi_mod usbcore i8042 usb_common virtio serio
[ 30.955195] CPU: 2 PID: 181 Comm: kworker/2:1H Not tainted 4.15.0-pf2 #1
[ 30.956649] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 30.958404] Workqueue: kblockd blk_mq_requeue_work
[ 30.959128] RIP: 0010:bfq_put_queue+0x10b/0x130
[ 30.960330] RSP: 0018:ffffc90000617c98 EFLAGS: 00010282
[ 30.961574] RAX: 0000000000000000 RBX: ffff88001d537210 RCX: 00000000ffffffff
[ 30.962990] RDX: 0000000000000000 RSI: ffff880018a300d8 RDI: ffff88001d537240
[ 30.964114] RBP: 0000000018a300a8 R08: 0000000000000041 R09: ffff88001d537210
[ 30.965449] R10: 0000000000432a7f R11: 000000000002000b R12: ffff88001d537240
[ 30.966798] R13: ffff88001941d6d9 R14: 0000000000000041 R15: 00000000ffffffff
[ 30.969154] FS: 0000000000000000(0000) GS:ffff88001f900000(0000) knlGS:0000000000000000
[ 30.972781] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 30.974310] CR2: 0000000000000028 CR3: 0000000004008004 CR4: 00000000003606e0
[ 30.975544] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 30.976963] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 30.980515] Call Trace:
[ 30.981893] bfq_finish_requeue_request+0x54/0x380
[ 30.983499] __blk_mq_requeue_request+0x5c/0x140
[ 30.988010] blk_mq_dispatch_rq_list+0x1b4/0x4c0
[ 30.989621] ? __switch_to_asm+0x34/0x70
[ 30.991699] ? __switch_to_asm+0x40/0x70
[ 30.994801] ? stub_ptregs_64+0x11/0x30
[ 30.996506] blk_mq_sched_dispatch_requests+0x105/0x190
[ 30.998842] __blk_mq_run_hw_queue+0x80/0x90
[ 31.002840] __blk_mq_delay_run_hw_queue+0x92/0xe0
[ 31.004873] blk_mq_run_hw_queue+0x25/0x90
[ 31.006766] blk_mq_run_hw_queues+0x3a/0x50
[ 31.008725] blk_mq_requeue_work+0x116/0x140
[ 31.011034] process_one_work+0x1df/0x420
[ 31.012841] worker_thread+0x2b/0x3d0
[ 31.014371] ? process_one_work+0x420/0x420
[ 31.016165] kthread+0x113/0x130
[ 31.018432] ? kthread_create_on_node+0x70/0x70
[ 31.020638] ? do_group_exit+0x33/0xa0
[ 31.022188] ret_from_fork+0x35/0x40
[ 31.024845] Code: c1 e8 06 83 e0 01 48 83 f8 01 45 19 f6 e8 be 3b 00 00 41 83 e6 ee 48 89 c7 41 83 c6 53 e8 8e 3b 00 00 49 89 d9 45 89 f0 44 89 f9 <48> 8b 70 28 48 c7 c2 12 be e5 81 55 4c 89 ef e8 11 0f e0 ff 8b
[ 31.037915] RIP: bfq_put_queue+0x10b/0x130 RSP: ffffc90000617c98
[ 31.040346] CR2: 0000000000000028
[ 31.042889] ---[ end trace 11f85b2ea2b00253 ]---
[ 31.046478] note: kworker/2:1H[181] exited with preempt_count 1
===

===
[ 48.629969] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 48.632678] IP: blk_flush_complete_seq+0x20a/0x300
[ 48.637504] PGD 0 P4D 0
[ 48.639647] Oops: 0002 [#1] PREEMPT SMP PTI
[ 48.641496] Modules linked in: nls_iso8859_1 nls_cp437 vfat fat crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd glue_helper bochs_drm cryptd ttm ppdev drm_kms_helper iTCO_wdt iTCO_vendor_support input_leds led_class intel_agp psmouse joydev drm intel_gtt parport_pc mousedev syscopyarea sysfillrect sysimgblt evdev fb_sys_fops parport lpc_ich agpgart mac_hid i2c_i801 qemu_fw_cfg rtc_cmos sch_fq_codel ip_tables x_tables xfs libcrc32c crc32c_generic dm_mod raid10 hid_generic md_mod usbhid hid sr_mod cdrom sd_mod uhci_hcd ahci xhci_pci libahci serio_raw ehci_pci atkbd xhci_hcd ehci_hcd virtio_net libps2 libata crc32c_intel scsi_mod virtio_pci usbcore virtio_ring usb_common virtio i8042 serio
[ 48.663536] CPU: 3 PID: 175 Comm: kworker/3:1H Not tainted 4.15.0-pf2 #1
[ 48.668487] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 48.672290] Workqueue: kblockd blk_mq_run_work_fn
[ 48.674271] RIP: 0010:blk_flush_complete_seq+0x20a/0x300
[ 48.676939] RSP: 0000:ffff88001f983ed0 EFLAGS: 00010086
[ 48.679617] RAX: ffff88001d721b60 RBX: ffff88001d721b40 RCX: ffff8800192f26a8
[ 48.681937] RDX: 0000000000000000 RSI: ffff88001d721b70 RDI: ffff8800192f2600
[ 48.684117] RBP: ffff88001da3a140 R08: ffff88001d721b50 R09: 0000000000000000
[ 48.688197] R10: ffff8800176fdb00 R11: 0000000000000040 R12: 0000000000000000
[ 48.690628] R13: ffff88001d721b90 R14: 0000000000000046 R15: ffff88001d721b40
[ 48.693943] FS: 0000000000000000(0000) GS:ffff88001f980000(0000) knlGS:0000000000000000
[ 48.698935] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 48.701592] CR2: 0000000000000000 CR3: 0000000004008002 CR4: 00000000003606e0
[ 48.703861] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 48.705994] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 48.708165] Call Trace:
[ 48.709827] <IRQ>
[ 48.712631] mq_flush_data_end_io+0xb3/0xf0
[ 48.714419] scsi_end_request+0x90/0x1e0 [scsi_mod]
[ 48.717553] scsi_io_completion+0x237/0x650 [scsi_mod]
[ 48.721822] flush_smp_call_function_queue+0x7c/0xf0
[ 48.726672] smp_call_function_single_interrupt+0x32/0xf0
[ 48.733743] call_function_single_interrupt+0xa2/0xb0
[ 48.737194] </IRQ>
[ 48.738656] RIP: 0010:_raw_spin_unlock_irqrestore+0x11/0x40
[ 48.741128] RSP: 0000:ffffc900005e3d30 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff04
[ 48.745138] RAX: 0000000000000001 RBX: ffff88001d640000 RCX: 0000000000000012
[ 48.747764] RDX: 0000000000040000 RSI: 0000000000000293 RDI: 0000000000000293
[ 48.752698] RBP: 0000000000000293 R08: ffffffffffffffff R09: 0000000000000090
[ 48.755910] R10: 0000000000432a3f R11: 000000000002000b R12: 0000000000000000
[ 48.760517] R13: ffff8800199ef800 R14: ffff880018d29948 R15: ffff8800199ef800
[ 48.771214] ata_scsi_queuecmd+0xa0/0x210 [libata]
[ 48.774631] scsi_dispatch_cmd+0xe8/0x260 [scsi_mod]
[ 48.777489] scsi_queue_rq+0x4cf/0x560 [scsi_mod]
[ 48.782246] blk_mq_dispatch_rq_list+0x8f/0x4c0
[ 48.787614] blk_mq_sched_dispatch_requests+0x105/0x190
[ 48.790303] __blk_mq_run_hw_queue+0x80/0x90
[ 48.795313] process_one_work+0x1df/0x420
[ 48.798006] worker_thread+0x2b/0x3d0
[ 48.801376] ? process_one_work+0x420/0x420
[ 48.804226] kthread+0x113/0x130
[ 48.806674] ? kthread_create_on_node+0x70/0x70
[ 48.809640] ret_from_fork+0x35/0x40
[ 48.812834] Code: 39 d0 0f 84 8f 00 00 00 48 8b 97 b0 00 00 00 49 c1 e0 04 45 31 e4 48 8b b7 a8 00 00 00 49 01 d8 48 8d 8f a8 00 00 00 48 89 56 08 <48> 89 32 49 8b 50 18 49 89 48 18 48 89 87 a8 00 00 00 48 89 97
[ 48.822452] RIP: blk_flush_complete_seq+0x20a/0x300 RSP: ffff88001f983ed0
[ 48.824908] CR2: 0000000000000000
[ 48.830677] ---[ end trace 4e5ef1b3dcbb32c5 ]---
[ 48.833655] Kernel panic - not syncing: Fatal exception in interrupt
[ 48.836166] Kernel Offset: disabled
[ 48.837150] ---[ end Kernel panic - not syncing: Fatal exception in interrupt
===

Revoking my Tested-by tag (:.