Hi, community! When trying to re-add an already removed disk from a RAID 10, the kernel crashes. Running on x86_64 ( Intel Xeon ) and Archlinux. I've created a script to reproduce this issue. #!/bin/sh mdadm --zero-superblock /dev/sdp4 mdadm --zero-superblock /dev/sdo4 mdadm --zero-superblock /dev/sdn4 mdadm --create -vvv --force --run --metadata=1.2 /dev/md0 --level=10 --chunk=128 --layout=f3 --raid-devices=3 /dev/sdp4 /dev/sdo4 /dev/sdn4 sleep 5 mdadm --fail -vvv /dev/md0 sdn4 sleep 5 mdadm --remove -vvv /dev/md0 sdn4 sleep 5 mdadm --add /dev/md0 /dev/sdn4 That is enough to trigger this issue. Should be related to RAID layout configuration. I cannot reproduce it with f2 or n2 ( but it triggers with f3 or l3 ). Tested with mdadm 4.0. Also tested on kernel 4.14.18 , 4.14.35 and 4.16.3 . Same issue on all of them. Has someone found something similar? I'm not a kernel expert but I will try to help as far as I can. Thanks. [ 55.951379] md/raid10:md0: Disk failure on sdn4, disabling device. [ 55.951379] md/raid10:md0: Operation continuing on 2 devices. [ 88.257917] md/raid10:md0: Disk failure on sdn4, disabling device. [ 88.257917] md/raid10:md0: Operation continuing on 2 devices. [ 98.347009] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [ 98.355783] IP: r10buf_pool_free+0x38/0xe0 [raid10] [ 98.361239] PGD 0 P4D 0 [ 98.364076] Oops: 0000 [#1] SMP PTI [ 98.367979] Modules linked in: raid10 md_mod mlx4_ib mlx4_en ib_core ipmi_ssif intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp mgag200 kvm_intel i2c_algo_bit ttm kvm drm_kms_helper drm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd nls_iso8859_1 glue_helper nls_cp437 cryptd agpgart input_leds joydev iTCO_wdt vfat syscopyarea intel_cstate evdev mousedev iTCO_vendor_support led_class sysfillrect fat sysimgblt intel_rapl_perf pcspkr mac_hid i2c_i801 lpc_ich mlx4_core fb_sys_fops e1000e ixgbe mei_me mei devlink mdio ptp pps_core dca shpchp ipmi_si ipmi_devintf wmi ipmi_msghandler button sch_fq_codel ip_tables x_tables xfs libcrc32c crc32c_generic sr_mod ses cdrom enclosure sd_mod hid_generic usbhid hid uas usb_storage isci ahci libsas libahci [ 98.447354] ehci_pci ehci_hcd crc32c_intel mpt3sas raid_class libata scsi_transport_sas usbcore usb_common scsi_mod [ 98.459136] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.35-1-lts #1 [ 98.466439] Hardware name: HDS Hitachi Flash Storage/Hitachi Flash Storage, BIOS 19.21 1/22/2016 [ 98.476269] task: ffffffff90012480 task.stack: ffffffff90000000 [ 98.482893] RIP: 0010:r10buf_pool_free+0x38/0xe0 [raid10] [ 98.488933] RSP: 0018:ffff8f6aff003db8 EFLAGS: 00010206 [ 98.494779] RAX: 0000000000000060 RBX: ffff8f6ae673be00 RCX: ffff8f6aff003e28 [ 98.502754] RDX: 0000000000000000 RSI: ffff8f6ae2b53c80 RDI: ffff8f6ae2b53c80 [ 98.510727] RBP: ffff8f6ae2b53ce0 R08: ffff8f6aff003e2c R09: 0000000000000001 [ 98.518711] R10: 0000000000000080 R11: 0000000000000000 R12: 0000000000000000 [ 98.526695] R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 [ 98.534679] FS: 0000000000000000(0000) GS:ffff8f6aff000000(0000) knlGS:0000000000000000 [ 98.543734] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 98.550161] CR2: 0000000000000050 CR3: 000000089500a001 CR4: 00000000001606f0 [ 98.558145] Call Trace: [ 98.560881] <IRQ> [ 98.563136] put_buf+0x19/0x20 [raid10] [ 98.567426] end_sync_request+0x6b/0x70 [raid10] [ 98.572591] end_sync_write+0x9b/0x160 [raid10] [ 98.577662] blk_update_request+0x78/0x2c0 [ 98.582254] scsi_end_request+0x2c/0x1e0 [scsi_mod] [ 98.587719] scsi_io_completion+0x22f/0x610 [scsi_mod] [ 98.593472] blk_done_softirq+0x8e/0xc0 [ 98.597767] __do_softirq+0xde/0x2b3 [ 98.601770] irq_exit+0xae/0xb0 [ 98.605285] do_IRQ+0x81/0xd0 [ 98.608606] common_interrupt+0x7d/0x7d [ 98.612898] </IRQ> [ 98.615252] RIP: 0010:cpuidle_enter_state+0xa2/0x2e0 [ 98.620806] RSP: 0018:ffffffff90003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff7c [ 98.630017] RAX: ffff8f6aff01f3c0 RBX: 00000016e5f01e98 RCX: 000000000000001f [ 98.638748] RDX: 00000016e5f01e98 RSI: fffff8ab2f1ab602 RDI: 0000000000000000 [ 98.647482] RBP: ffff8f6aff028a70 R08: 00000000ffffffff R09: 000000000000000a [ 98.656209] R10: ffffffff90003e70 R11: 000000000000000f R12: 0000000000000001 [ 98.664925] R13: ffffffff900ac098 R14: 0000000000000000 R15: 00000016e5efe111 [ 98.673642] do_idle+0x179/0x1d0 [ 98.677988] cpu_startup_entry+0x6f/0x80 [ 98.683100] start_kernel+0x4ae/0x4ce [ 98.687910] secondary_startup_64+0xa5/0xb0 [ 98.693298] Code: 45 31 e4 55 53 48 83 ec 08 48 63 46 78 48 89 3c 24 44 8d 68 ff 41 83 fd ff 74 6f 48 8b 34 24 48 c1 e0 05 48 8d 2c 06 4c 8b 75 28 <4d> 8b 66 50 4d 8d 7c 24 08 49 8d 9c 24 88 00 00 00 49 8b 3f 48 [ 98.715888] RIP: r10buf_pool_free+0x38/0xe0 [raid10] RSP: ffff8f6aff003db8 [ 98.724296] CR2: 0000000000000050 [ 98.728716] ---[ end trace 26fbc93e654360aa ]--- [ 98.738337] Kernel panic - not syncing: Fatal exception in interrupt [ 98.746173] Kernel Offset: 0xe000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 98.762456] ---[ end Kernel panic - not syncing: Fatal exception in interrupt -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
