------- Comment From niklas.schne...@ibm.com 2020-09-01 04:18 EDT------- Thanks for your quick work, I can confirm that this works as designed on the 5.4.0-46-generic kernel from proposed.
-- 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/1891437 Title: [UBUNTU 20.04] zPCI: Enabling of a reserved PCI function regression introduced by multi-function support Status in Ubuntu on IBM z Systems: Fix Committed Status in linux package in Ubuntu: Fix Committed Status in linux source package in Focal: Fix Committed Status in linux source package in Groovy: Fix Committed Bug description: SRU Justification: ================== [Impact] * If a NVMe drive is assigned/hotplugged to a Linux on s390x LPAR, a bug in lib/list_debug.c is hit and the device is not accessible. * The reason is a missing /dev/ file -- lspci does not report it either. [Fix] * 3047766bc6ec9c6bc9ece85b45a41ff401e8d988 3047766bc6ec "s390/pci: fix enabling a reserved PCI function" [Test Case] * Assign a NMVe drive to your LPAR (using the HMC) * Unassign the NVMe drive from your LPAR * Reassign it to your LPAR again * Look at dmesg for 'kernel BUG at lib/list_debug.c' [Regression Potential] * There is some regression risk with having code changes in the zPCI sub-system. * zPCI is the PCI implementation on s390x, modifications here do not affect any other architecture. * It could be that PCI events do not work anymore and NVMe devices don't IPL (boot) on s390x anymore. * However, the code changes below to a single file: arch/s390/pci/pci_event.c * and IPL from NVMe is brand new in Ubuntu for s390x, * and zPCI devices are less wide-spread compared to ccw devices on s390x. * On top a test kernel was build and made available for further testing. [Other] * Since the fix/patch got upstream accepted with kernel v5.8-rc5, it's already in the groovy proposed kernel 5.8, hence this SRU is for focal only. __________ When a NVMe drive is assigned/hotplugged to a Linux LPAR then a bug is hit in lib/list_debug.c. And the device is not accessible, there is no /dev/ file and lspci does not report it also. [ 1681.564462] list_add double add: new=00000000eed0f808, prev=00000000eed0f808, next=000000004070a300. [ 1681.564489] ------------[ cut here ]------------ [ 1681.564490] kernel BUG at lib/list_debug.c:31! [ 1681.564504] monitor event: 0040 ilc:2 [#1] SMP [ 1681.564507] Modules linked in: ip6t_REJECT nf_reject_ipv6 ip6t_rpfilter ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat iptable_mangle iptable_raw iptable_security nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter s390_trng ghash_s390 prng aes_s390 des_s390 libdes sha512_s390 vfio_ccw sha1_s390 vfio_mdev mdev chsc_sch vfio_iommu_type1 eadm_sch vfio ip_tables dm_service_time nvme crc32_vx_s390 sha256_s390 sha_common nvme_core qeth_l2 zfcp qeth scsi_transport_fc qdio ccwgroup dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua pkey zcrypt [ 1681.564534] CPU: 6 PID: 139 Comm: kmcheck Not tainted 5.8.0-rc1+ #2 [ 1681.564535] Hardware name: IBM 8561 T01 701 (LPAR) [ 1681.564536] Krnl PSW : 0704c00180000000 000000003ffcadb8 (__list_add_valid+0x70/0xa8) [ 1681.564544] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 [ 1681.564545] Krnl GPRS: 0000000000000040 0000000000000027 0000000000000058 0000000000000007 [ 1681.564546] 000000003ffcadb4 0000000000000000 0000000000000000 000003e0051a7ce0 [ 1681.564547] 000000004070a300 00000000eed0f808 00000000eed0f808 000000004070a300 [ 1681.564548] 00000000f56a2000 0000000040c2c788 000000003ffcadb4 000003e0051a7bc8 [ 1681.564583] Krnl Code: 000000003ffcada8: c02000302b09 larl %r2,00000000405d03ba 000000003ffcadae: c0e5ffdd30b1 brasl %r14,000000003fb70f10 #000000003ffcadb4: af000000 mc 0,0 >000000003ffcadb8: b9040054 lgr %r5,%r4 000000003ffcadbc: c02000302aad larl %r2,00000000405d0316 000000003ffcadc2: b9040041 lgr %r4,%r1 000000003ffcadc6: c0e5ffdd30a5 brasl %r14,000000003fb70f10 000000003ffcadcc: af000000 mc 0,0 [ 1681.564592] Call Trace: [ 1681.564594] [<000000003ffcadb8>] __list_add_valid+0x70/0xa8 [ 1681.564596] ([<000000003ffcadb4>] __list_add_valid+0x6c/0xa8) [ 1681.564599] [<000000003faf2920>] zpci_create_device+0x60/0x1b0 [ 1681.564601] [<000000003faf704a>] zpci_event_availability+0x282/0x2f0 [ 1681.564605] [<0000000040367848>] chsc_process_crw+0x2b8/0xa18 [ 1681.564607] [<000000004036f35c>] crw_collect_info+0x254/0x348 [ 1681.564610] [<000000003fb2a6ea>] kthread+0x14a/0x168 [ 1681.564613] [<00000000403a55c0>] ret_from_fork+0x24/0x2c [ 1681.564614] Last Breaking-Event-Address: [ 1681.564618] [<000000003fb70f62>] printk+0x52/0x58 [ 1681.564620] ---[ end trace 7ea67c348aa67e14 ]--- uname: Linux t83lp49.lnxne.boe 5.8.0-rc1+ #2 SMP Thu Jun 18 12:38:02 CEST 2020 s390x s390x s390x GNU/Linux How to reproduce: 1. Unassign a NVMe drive in HMC from your LPAR 2. Reassign it to your LPAR again 3. dmesg This issue is fixed by the following upstream commit that is also CCed to stable so might be coming in over the stable pulls in parallel: 3047766bc6ec ("s390/pci: fix enabling a reserved PCI function") To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1891437/+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
