Re: panic happened on 5.8.6-rc2-650d8f2

[Rachel Sibley <rasibley@xxxxxxxxxx>]

On 9/7/20 3:05 AM, Paolo Valente wrote:
> Hi Jianlin,
> given the stack trace and the goal of commit
> 2de791ab4918969d8108f15238a701968375f235 ("bfq: fix blkio cgroup
> leakage v4"), this failure might be related to that commit.  Could you
> please try reverting that commit and report back?

Hi Paolo/Jianlin,

I cloned the original job and was unable to reproduce the panic, I also don't see it
for any previous or succeeding pipeline for stable tree. I setup a check to automatically
tag the related pipeline in case we're able to reproduce it. We can also work on testing
with the patch reverted, if we see it again we'll follow up in this thread.

Thank you,
Rachel

> Thanks,
> Paolo
>
> > Il giorno 7 set 2020, alle ore 04:02, Jens Axboe <axboe@xxxxxxxxx> ha scritto:
> >
> > CC Paolo
> >
> >
> > On 9/6/20 6:36 PM, Jianlin Shi wrote:
> > > Hi,
> > >
> > > panic happened when we run jobs on 5.8.6-rc2-650d8f2:
> > > https://beaker.engineering.redhat.com/recipes/8756377#task115008997
> > >
> > > and the core trace is as follows, have you ever seen this before?
> > >
> > > [ 7522.385926] BUG: kernel NULL pointer dereference, address: 0000000000000000
> > > [ 7522.393694] #PF: supervisor read access in kernel mode
> > > [ 7522.399425] #PF: error_code(0x0000) - not-present page
> > > [ 7522.405154] PGD 0 P4D 0
> > > [ 7522.407977] Oops: 0000 [#1] SMP PTI
> > > [ 7522.411866] CPU: 14 PID: 668 Comm: kworker/14:1H Kdump: loaded
> > > Tainted: G             L    5.8.6-rc2-650d8f2.cki #1
> > > [ 7522.423510] Hardware name: Dell Inc. PowerEdge R630/0CNCJW, BIOS
> > > 1.2.10 03/09/2015
> > > [ 7522.431959] Workqueue: kblockd blk_mq_run_work_fn
> > > [ 7522.437206] RIP: 0010:__list_del_entry_valid+0x2d/0x4c
> > > [ 7522.442936] Code: 4c 8b 47 08 48 b8 00 01 00 00 00 00 ad de 48 39
> > > c2 0f 84 71 00 00 00 48 b8 22 01 00 00 00 00 ad de 49 39 c0 0f 84 91
> > > 00 00 00 <49> 8b 30 48 39 fe 0f 85 71 00 00 00 48 8b 52 08 48 39 f2 0f
> > > 85 56
> > > [ 7522.463891] RSP: 0018:ffffa5b9009dfcd8 EFLAGS: 00010017
> > > [ 7522.469719] RAX: dead000000000122 RBX: ffff8b458d4c9950 RCX:
> > > 0000000000000000
> > > [ 7522.477680] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> > > ffff8b448a753938
> > > [ 7522.485640] RBP: ffff8b448a753898 R08: 0000000000000000 R09:
> > > ffff8b45bb6bb32c
> > > [ 7522.493600] R10: 0000000000000018 R11: 0000000000000018 R12:
> > > ffff8b448a753810
> > > [ 7522.501560] R13: ffff8b44993e2800 R14: 0000000000000000 R15:
> > > ffff8b458d07c900
> > > [ 7522.509520] FS:  0000000000000000(0000) GS:ffff8b45bfd80000(0000)
> > > knlGS:0000000000000000
> > > [ 7522.518548] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > [ 7522.524957] CR2: 0000000000000000 CR3: 0000000875570005 CR4:
> > > 00000000001606e0
> > > [ 7522.532917] Call Trace:
> > > [ 7522.535647]  bfq_idle_extract+0x52/0xb0
> > > [ 7522.539926]  bfq_put_idle_entity+0x12/0x60
> > > [ 7522.544494]  bfq_bfqq_served+0xb0/0x190
> > > [ 7522.548770]  bfq_dispatch_request+0x2c2/0x1070
> > > [ 7522.553727]  blk_mq_do_dispatch_sched+0xa4/0x140
> > > [ 7522.558879]  ? newidle_balance+0x1c0/0x390
> > > [ 7522.563446]  __blk_mq_sched_dispatch_requests+0x159/0x160
> > > [ 7522.569467]  blk_mq_sched_dispatch_requests+0x30/0x60
> > > [ 7522.575102]  __blk_mq_run_hw_queue+0x49/0x110
> > > [ 7522.579962]  process_one_work+0x1b4/0x370
> > > [ 7522.584434]  worker_thread+0x53/0x3e0
> > > [ 7522.588517]  ? process_one_work+0x370/0x370
> > > [ 7522.593180]  kthread+0x119/0x140
> > > [ 7522.596779]  ? __kthread_bind_mask+0x60/0x60
> > > [ 7522.601541]  ret_from_fork+0x22/0x30
> > > [ 7522.605528] Modules linked in: scsi_transport_iscsi crypto_user
> > > can_bcm pptp gre l2tp_ip6 l2tp_ip l2tp_core ip6_udp_tunnel udp_tunnel
> > > rfcomm can_raw hidp bnep nfc af_key mpls_router ip_tunnel
> > > vsock_loopback vmw_vsock_virtio_transport_common
> > > vmw_vsock_vmci_transport vsock vmw_vmci kcm ieee802154_socket
> > > ieee802154 bluetooth ecdh_generic ecc fcrypt pcbc rxrpc pppoe pppox
> > > smc ib_core atm can mlx4_en mlx4_core n_gsm pps_ldisc slcan
> > > ppp_synctty n_hdlc mkiss ax25 ppp_async ppp_generic slip slhc nls_utf8
> > > isofs minix binfmt_misc nfsv3 nfs_acl rds brd exfat vfat fat loop sctp
> > > tun xt_multiport xt_nat xt_addrtype xt_mark xt_conntrack xt_MASQUERADE
> > > nft_counter xt_comment nft_compat nft_chain_nat nf_nat nf_conntrack
> > > nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink overlay fuse
> > > rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache
> > > rfkill intel_rapl_msr intel_rapl_common sb_edac x86_pkg_temp_thermal
> > > intel_powerclamp coretemp iTCO_wdt intel_pmc_bxt iTCO_vendor_support
> > > sunrpc dcdbas
> > > [ 7522.605556]  kvm_intel kvm irqbypass rapl intel_cstate
> > > intel_uncore pcspkr ipmi_ssif lpc_ich mei_me mei igb dca ipmi_si
> > > ipmi_devintf ipmi_msghandler acpi_power_meter ip_tables xfs mgag200
> > > lpfc drm_vram_helper drm_kms_helper cec nvmet_fc drm_ttm_helper nvmet
> > > ttm crct10dif_pclmul nvme_fc crc32_pclmul crc32c_intel nvme_fabrics
> > > drm ghash_clmulni_intel i2c_algo_bit nvme_core megaraid_sas
> > > scsi_transport_fc wmi [last unloaded: dummy]
> > > [ 7522.744918] CR2: 0000000000000000
> > > [ 7522.748613] ---[ end trace ed34032a61d7e2a6 ]---
> > >
> > > Thanks & Best Regards,
> > >
> > > Jianlin Shi
> >
> >
> > --
> > Jens Axboe