Hey Or & Sagi, Quick CMA related question for you.. I've been hitting the following NULL pointer dereference during reboot using a v3.14.y based kernel with Sagi's latest ib_isert fixes in the stable-queue from v3.17. Note this system was not performing /etc/init.d/target stop during reboot to take down the configfs layout, and no actual iser logins or sessions had been previously established on iser enabled network portal in question: [info] Will now restart. [ 111.076328] kvm: exiting hardware virtualization [ 111.083670] sd 9:0:3:0: [sdi] Synchronizing SCSI cache [ 111.089825] sd 9:0:2:0: [sdh] Synchronizing SCSI cache [ 111.095924] sd 9:0:1:0: [sdg] Synchronizing SCSI cache [ 111.103375] sd 9:0:0:0: [sdf] Synchronizing SCSI cache [ 111.109707] sd 8:0:3:0: [sde] Synchronizing SCSI cache [ 111.116036] sd 8:0:2:0: [sdd] Synchronizing SCSI cache [ 111.122368] sd 8:0:1:0: [sdc] Synchronizing SCSI cache [ 111.128723] sd 8:0:0:0: [sdb] Synchronizing SCSI cache [ 111.134979] sd 0:0:0:0: [sda] Synchronizing SCSI cache [ 111.273440] isert_cma_handler: event 11 status 0 conn ffff880815896000 id ffff88101440d400 [ 111.282871] isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [ 111.290808] BUG: unable to handle kernel NULL pointer dereference at (null) [ 111.299886] IP: [< (null)>] (null) [ 111.305736] PGD 10186c6067 PUD 1016d84067 PMD 0 [ 111.311271] Oops: 0010 [#1] SMP [ 111.315169] Modules linked in: ib_isert ib_ipoib mlx4_ib rpcsec_gss_krb5 nfsv4 ip_tables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 nf_nat nf_conntrack ip6table_filter ip6_tables ebtables x_tables iscsi_target_mod ib_srpt tcm_qla2xxx tcm_loop vhost_scsi vhost tcm_fc libfc target_core_file target_core_iblock target_core_pscsi target_core_mod 8021q garp stp mrp llc nfsd auth_rpcgss oid_registry nfs_acl nfs lockd sunrpc loop x86_pkg_temp_thermal intel_powerclamp crct10dif_pclmul sb_edac crc32_pclmul ioatdma ghash_clmulni_intel lpc_ich edac_core mfd_core i2c_i801 ipmi_si processor thermal_sys button md_mod sg hid_generic isci usbhid mpt3sas ixgbe mlx4_core libsas raid_class hid igb scsi_transport_sas qla2xxx mdio i2c_algo_bit i2c_core scsi_transport_fc dca [ 111.398587] CPU: 6 PID: 138 Comm: kworker/6:1 Not tainted 3.14.13+ #6 [ 111.405902] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.01.0002.082220131453 08/22/2013 [ 111.417530] Workqueue: events isert_disconnect_work [ib_isert] [ 111.424254] task: ffff88101a9bcb60 ti: ffff8810152bc000 task.ti: ffff8810152bc000 [ 111.432762] RIP: 0010:[<0000000000000000>] [< (null)>] (null) [ 111.441357] RSP: 0018:ffff8810152bddb0 EFLAGS: 00010087 [ 111.447407] RAX: ffff8808158969e8 RBX: 0000000000000000 RCX: 0000000000000000 [ 111.455499] RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff8808158969e8 [ 111.463593] RBP: ffff880815896600 R08: 0000000000000000 R09: 000000000000074f [ 111.471685] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 111.479779] R13: 0000000000000000 R14: 0000000000000003 R15: ffff880815896be8 [ 111.487872] FS: 0000000000000000(0000) GS:ffff88101f200000(0000) knlGS:0000000000000000 [ 111.497061] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 111.503598] CR2: 0000000000000000 CR3: 00000010040ce000 CR4: 00000000001407e0 [ 111.511691] Stack: [ 111.514046] ffffffff810f40ac ffff8810152bde08 00000001152bddc8 ffff88101f20f440 [ 111.522812] ffff8808158965f8 ffff8808158965f0 0000000000000292 ffff88101f216700 [ 111.531578] 0000000000000000 0000000000000180 ffffffff810f49ca ffff8808158965a8 [ 111.540344] Call Trace: [ 111.543195] [<ffffffff810f40ac>] ? __wake_up_common+0x4c/0x80 [ 111.549836] [<ffffffff810f49ca>] ? complete+0x3a/0x60 [ 111.555698] [<ffffffff810ccecf>] ? process_one_work+0x16f/0x430 [ 111.562528] [<ffffffff810ce6d6>] ? worker_thread+0x116/0x3d0 [ 111.569065] [<ffffffff810ce5c0>] ? manage_workers.isra.21+0x2e0/0x2e0 [ 111.576482] [<ffffffff810d49bc>] ? kthread+0xbc/0xe0 [ 111.582243] [<ffffffff810d4900>] ? flush_kthread_worker+0x80/0x80 [ 111.589273] [<ffffffff8164d8cc>] ? ret_from_fork+0x7c/0xb0 [ 111.595616] [<ffffffff810d4900>] ? flush_kthread_worker+0x80/0x80 [ 111.602639] Code: Bad RIP value. [ 111.606631] RIP [< (null)>] (null) [ 111.612576] RSP <ffff8810152bddb0> [ 111.616583] CR2: 0000000000000000 [ 111.620400] ---[ end trace 8e386ea065bef2ce ]--- [ 111.634392] BUG: unable to handle kernel paging request at ffffffffffffffd8 [ 111.642470] IP: [<ffffffff810d4d67>] kthread_data+0x7/0x10 [ 111.648806] PGD 1c0d067 PUD 1c0f067 PMD 0 [ 111.653761] Oops: 0000 [#2] SMP [ 111.657653] Modules linked in: ib_isert ib_ipoib mlx4_ib rpcsec_gss_krb5 nfsv4 ip_tables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 nf_nat nf_conntrack ip6table_filter ip6_tables ebtables x_tables iscsi_target_mod ib_srpt tcm_qla2xxx tcm_loop vhost_scsi vhost tcm_fc libfc target_core_file target_core_iblock target_core_pscsi target_core_mod 8021q garp stp mrp llc nfsd auth_rpcgss oid_registry nfs_acl nfs lockd sunrpc loop x86_pkg_temp_thermal intel_powerclamp crct10dif_pclmul sb_edac crc32_pclmul ioatdma ghash_clmulni_intel lpc_ich edac_core mfd_core i2c_i801 ipmi_si processor thermal_sys button md_mod sg hid_generic isci usbhid mpt3sas ixgbe mlx4_core libsas raid_class hid igb scsi_transport_sas qla2xxx mdio i2c_algo_bit i2c_core scsi_transport_fc dca [ 111.740836] CPU: 6 PID: 138 Comm: kworker/6:1 Tainted: G D 3.14.13+ #6 [ 111.749239] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.01.0002.082220131453 08/22/2013 [ 111.760875] task: ffff88101a9bcb60 ti: ffff8810152bc000 task.ti: ffff8810152bc000 [ 111.769383] RIP: 0010:[<ffffffff810d4d67>] [<ffffffff810d4d67>] kthread_data+0x7/0x10 [ 111.778472] RSP: 0018:ffff8810152bda70 EFLAGS: 00010002 [ 111.784522] RAX: 0000000000000000 RBX: 0000000000000006 RCX: 000000000000000f [ 111.792615] RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffff88101a9bcb60 [ 111.800708] RBP: ffff88101a9bcb60 R08: 0000000000000001 R09: 0000000000000001 [ 111.808801] R10: 0000000000000001 R11: ffffea00404e9b80 R12: ffff88101f212dc0 [ 111.816894] R13: 0000000000000006 R14: ffff88101a9bcb50 R15: ffff88101a9bcb60 [ 111.824989] FS: 0000000000000000(0000) GS:ffff88101f200000(0000) knlGS:0000000000000000 [ 111.834179] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 111.840716] CR2: 0000000000000028 CR3: 00000010040ce000 CR4: 00000000001407e0 [ 111.848809] Stack: [ 111.851162] ffffffff810ceb58 ffff88101a9bcf48 ffffffff81641ccd ffff881014f40190 [ 111.859910] 0000000000000086 0000000000012dc0 ffff8810152bdfd8 0000000000012dc0 [ 111.868675] ffff88101a9bcb60 ffff88101a9bcb60 ffff88101a9bd168 ffff88101a9bce40 [ 111.877433] Call Trace: [ 111.880277] [<ffffffff810ceb58>] ? wq_worker_sleeping+0x8/0x80 [ 111.887012] [<ffffffff81641ccd>] ? __schedule+0x46d/0x760 [ 111.893264] [<ffffffff810b44d2>] ? do_exit+0x6c2/0xa30 [ 111.899223] [<ffffffff816466f2>] ? oops_end+0xa2/0x140 [ 111.905184] [<ffffffff8163a8d8>] ? no_context+0x264/0x28f [ 111.921058] [<ffffffff81648d72>] ? __do_page_fault+0xd2/0x510 [ 111.927696] [<ffffffff8164932d>] ? __atomic_notifier_call_chain+0xd/0x20 [ 111.935409] [<ffffffff813e41a5>] ? notify_update+0x25/0x30 [ 111.941753] [<ffffffff813e4a60>] ? vt_console_print+0x230/0x3c0 [ 111.948576] [<ffffffff81645af8>] ? page_fault+0x28/0x30 [ 111.954628] [<ffffffff810f40ac>] ? __wake_up_common+0x4c/0x80 [ 111.961265] [<ffffffff810f49ca>] ? complete+0x3a/0x60 [ 111.967124] [<ffffffff810ccecf>] ? process_one_work+0x16f/0x430 [ 111.973955] [<ffffffff810ce6d6>] ? worker_thread+0x116/0x3d0 [ 111.980495] [<ffffffff810ce5c0>] ? manage_workers.isra.21+0x2e0/0x2e0 [ 111.987909] [<ffffffff810d49bc>] ? kthread+0xbc/0xe0 [ 111.993671] [<ffffffff810d4900>] ? flush_kthread_worker+0x80/0x80 [ 112.000697] [<ffffffff8164d8cc>] ? ret_from_fork+0x7c/0xb0 [ 112.007043] [<ffffffff810d4900>] ? flush_kthread_worker+0x80/0x80 [ 112.014063] Code: 00 00 00 00 65 48 8b 04 25 c0 b8 00 00 48 8b 80 90 03 00 00 48 8b 40 c8 48 c1 e8 02 83 e0 01 c3 0f 1f 40 00 48 8b 87 90 03 00 00 <48> 8b 40 d8 c3 0f 1f 40 00 48 83 ec 18 ba 08 00 00 00 48 c7 44 [ 112.041059] RIP [<ffffffff810d4d67>] kthread_data+0x7/0x10 [ 112.047490] RSP <ffff8810152bda70> [ 112.051487] CR2: ffffffffffffffd8 [ 112.055301] ---[ end trace 8e386ea065bef2cf ]--- [ 112.068495] Fixing recursive fault but reboot is needed! AFAICT, it looks like the assumption in isert_disconnected_handler() to dereference rdma_cm_id->context as isert_conn (in all cases) is wrong, and the above RDMA_CM_EVENT_DEVICE_REMOVAL has iscsi_np stored in ->context from the original rdma_create_id() at isert_setup_np() time. So, is there a way to tell the difference how rdma_cm_id->context should be dereferenced when DEVICE_REMOVAL occurs..? Does DEVICE_REMOVAL occur on just the listener rdma_cm_id, or on all accepted children as well..? Anything else to consider wrt to other CMA events being kicked off into isert_disconnected_handler()..? --nab -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
