ubuntu@grotrian:~$ cat /proc/version Linux version 4.10.0-28-generic (buildd@bos01-arm64-012) (gcc version 6.3.0 20170406 (Ubuntu/Linaro 6.3.0-12ubuntu2) ) #32-Ubuntu SMP Fri Jun 30 05:33:10 UTC 2017 ubuntu@grotrian:~$ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-4.10.0-28-generic root=UUID=fcf02e40-f2bd-4c9f-a9bd-1abe132cbc9e ro acpi=on crashkernel=1G-:512M ubuntu@grotrian:~$ echo c | sudo tee /proc/sysrq-trigger c
<crash/reboot> ubuntu@grotrian:~$ sudo crash /usr/lib/debug/boot/vmlinux-4.10.0-28-generic /var/crash/201707102147/dump.201707102147 crash 7.1.8 Copyright (C) 2002-2016 Red Hat, Inc. Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005, 2011 NEC Corporation Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. This program is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Enter "help copying" to see the conditions. This program has absolutely no warranty. Enter "help warranty" for details. GNU gdb (GDB) 7.6 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "aarch64-unknown-linux-gnu"... KERNEL: /usr/lib/debug/boot/vmlinux-4.10.0-28-generic DUMPFILE: /var/crash/201707102147/dump.201707102147 [PARTIAL DUMP] CPUS: 48 DATE: Mon Jul 10 21:47:34 2017 UPTIME: 00:35:42 LOAD AVERAGE: 0.13, 0.31, 0.26 TASKS: 578 NODENAME: grotrian RELEASE: 4.10.0-28-generic VERSION: #32-Ubuntu SMP Fri Jun 30 05:33:10 UTC 2017 MACHINE: aarch64 (unknown Mhz) MEMORY: 128 GB PANIC: "sysrq: SysRq : Trigger a crash" PID: 5136 COMMAND: "tee" TASK: ffff801f4682ba00 [THREAD_INFO: ffff801f4682ba00] CPU: 45 STATE: TASK_RUNNING (SYSRQ) crash> bt PID: 5136 TASK: ffff801f4682ba00 CPU: 45 COMMAND: "tee" #0 [ffff801f48e8ba40] crash_kexec at ffff00000816ce94 #1 [ffff801f48e8ba70] die at ffff00000808b23c #2 [ffff801f48e8bab0] do_page_fault at ffff000008a099e4 #3 [ffff801f48e8bb20] do_translation_fault at ffff000008a09cb8 #4 [ffff801f48e8bb50] do_mem_abort at ffff000008081490 #5 [ffff801f48e8bd50] el1_ia at ffff000008082f28 PC: ffff00000863ffcc [sysrq_handle_crash+36] LR: ffff000008640c54 [__handle_sysrq+292] SP: ffff801f48e8bd50 PSTATE: 00400145 X29: ffff801f48e8bd50 X28: ffff801f4682ba00 X27: ffff000008a22000 X26: 0000000000000040 X25: 0000000000000123 X24: 0000000000000015 X23: 0000000000000000 X22: 0000000000000004 X21: ffff0000092a9500 X20: 0000000000000063 X19: ffff000009231000 X18: ffffffffffffffff X17: 0000ffff796f43d0 X16: ffff00000829e9a8 X15: ffff000009208b10 X14: ffff00008935c7bf X13: ffff00000935c7cd X12: 7565726f632f5345 X11: ffff000009231000 X10: 0000000005f5e0ff X9: 00000000ffffffd0 X8: ffff0000086676b0 X7: 6767697254203a20 X6: 00000000000004fb X5: 0000000000000000 X4: 0000000000000000 X3: 0000000000000000 X2: 0000000000040a11 X1: 0000000000000000 X0: 0000000000000001 #6 [ffff801f48e8bd60] __handle_sysrq at ffff000008640c50 #7 [ffff801f48e8bda0] write_sysrq_trigger at ffff000008641108 #8 [ffff801f48e8bdc0] proc_reg_write at ffff00000831ec84 #9 [ffff801f48e8be00] __vfs_write at ffff00000829beac #10 [ffff801f48e8be30] vfs_write at ffff00000829d3c8 #11 [ffff801f48e8be70] sys_write at ffff00000829ea10 #12 [ffff801f48e8bed0] el0_svc_naked at ffff0000080838ec PC: 0000000000000003 LR: 0000ffff79745cb8 SP: 0000000020000000 X29: 0000ffffd17124b0 X28: 0000ffff796f5498 X27: 0000ffffd17124b0 X26: 0000000000000001 X25: 000000002d76dbf0 X24: 0000000000417000 X23: 0000000000000002 X22: 0000000000000002 X21: 0000ffff797c9638 X20: 0000000000000002 X19: 000000002d76dbf0 X18: 0000ffffd1712638 X17: 0000000000000002 X16: 0000000000040a11 X15: 0000ffff796f43d0 X14: 0000000000000000 X13: 00000000000007fe X12: 0000000000000018 X11: 0000000000000000 X10: 7565726f632f5345 X9: 0000000000000000 X8: 0101010101010101 X7: 000000002d76d050 X6: 0000000000000040 X5: 0000000000000240 X4: 000000000040582e X3: 00000000fbad2c87 X2: 00000000ffffffff X1: 0000000000000000 X0: 0000000000000002 ORIG_X0: 0000000000000000 SYSCALLNO: 0 PSTATE: 00000040 crash> ** Tags removed: verification-needed-zesty ** Tags added: verification-done-zesty -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to kexec-tools in Ubuntu. https://bugs.launchpad.net/bugs/1694859 Title: arm64 kernel crashdump support Status in kexec-tools package in Ubuntu: Fix Released Status in linux package in Ubuntu: Fix Committed Status in makedumpfile package in Ubuntu: Confirmed Status in kexec-tools source package in Xenial: In Progress Status in linux source package in Xenial: Won't Fix Status in makedumpfile source package in Xenial: Confirmed Status in kexec-tools source package in Yakkety: In Progress Status in linux source package in Yakkety: Won't Fix Status in makedumpfile source package in Yakkety: Confirmed Status in kexec-tools source package in Zesty: In Progress Status in linux source package in Zesty: Fix Committed Status in makedumpfile source package in Zesty: Confirmed Bug description: Note: Updates are being staged at ppa:dannf/arm64-kdump. [Impact] It is not possible to collect a kernel crash dump from a crashed arm64 server for later debugging. [Test Case] sudo apt install kdump-tools (reboot, so crashkernel= is added to the kernel commandline) echo c | sudo tee /proc/sysrq-trigger Crash dump should occur, with artifacts collected in /var/crash. If you want to verify that the dump is usable, install the corresponding linux-image-<ver>-dbgsym package and run: sudo crash /usr/lib/debug/boot/vmlinux-<ver> /var/crash/<crash>/dump.<crash> crash should successfully load, placing you at a "crash>" prompt. At that prompt, you can issue the 'bt' command to see a backtrace. Note: you need crash from zesty (7.1.8-1ubuntu1) or later. [Regression Risk] = Kernel = 3 patches here touch code outside of arch/arm64/: memblock: add memblock_clear_nomap() This adds a new function with no callers, so regression risk is negligible. (A later patch adds a call to it under arch/arm64/). memblock: add memblock_cap_memory_range() This refactors some of the code in memblock_mem_limit_remove_map() into a new function. The only existing caller of memblock_mem_limit_remove_map() is under arch/arm64/, so the regression risk outside of arm64 is negligible. efi/libstub/arm*: Set default address and size cells values for an empty dtb Because this code is for EFI platforms that support device-tree, it is de-facto ARM-specific (as noted in the patch title). For arm64, we have mitigated the risk by explicit regression testing on several platforms: - Qualcomm QDF2400 - Cavium ThunderX CRB1S - HP m400 (X-Gene) - HiSilicon D05 (Hi07) = kexec-tools = == zesty == For zesty, 10 patches are required to add kdump support. 0001-kexec-extend-the-semantics-of-kexec_iomem_for_each_l.patch: This modifies a function used on armhf & x86. The description explains the change, and why it does not impact those archs: ----- The current users of kexec_iomem_for_each_line(), arm, sh and x86, will not be affected by this change because * arm The callback function only returns -1 or 0, and the return value of kexec_iomem_for_each_line() will never be used. * sh, x86 The callback function may return (-1 for sh,) 0 or 1, but always returns 1 once we have reached the maximum number of entries allowed. Even so the current kexec_iomem_for_each_line() counts them up. This change actually fixes this bug. ----- 0002-kexec-generalize-and-rename-get_kernel_stext_sym.patch: This generalizes a function that was duplicated by arm & x86 and makes it common so arm64 can use it. The remaining 8 of these only touch code in kexec/arch/arm64, so regression risk for other architectures is negligible. Finally, I have tested this update on both i386 and amd64 VMs. i386 crashes do not currently work in zesty (filed LP: #1699874), and my test results show no change there. amd64 worked before, and continues to work with these changes. == yakkety == Since yakkety is based on an older upstream, 6 additional patches are required: arm-fix-get_kernel_stext_sym-to-close-its-file.patch: This is a cleanup patch, cherry-picked because it allows later patches to apply w/o backporting. ARM-specific. kexec-add-max_size-to-memory_ranges.patch: Adds a new element to struct, to be used by later commits. kexec-add-generic-helper-to-add-to-memoryq_regions.patch, kexec-add-mem_regions-sorting-implementation.patch, kexec-add-helper-to-exlude-a-region-from-a-set-of-me.patch, kexec-fix-mem_regions_sort.patch: These patches only add new functions, which will be used by later patches. kexec-arch-i386-Add-support-for-KASLR-memory-randomi.patch: This is a bug fix or i386 that allows later patches to apply w/o backporting. kdump support for i386 is apparently broken for the yakkety kernel (see LP: #1699874) so, if this introduces a regression, it won't be detectable. (I checked to see if this *fixes* i386 crashdumps - it does not). Note that, while makedumpfile in >= zesty is new enough to work on arm64, the yakkety version does not. kdump-tools falls back to copying the entire vmcore, which is what I tested. As with zesty, I have tested this update on both i386 and amd64 VMs. i386 crashes do not currently work in yakkety, and my test results show no change there. amd64 worked before, and continues to work with these changes. = xenial = The patchset needed for xenial is identical to the patchset for yakkety. The only additional change is to add arm64 to the list of archs that get a /etc/default/grub.d snippet (in yakkety that snippet moved over to kdump-tools), and that has negligible regression risk for !arm64. I performed the same testing as with yakkety. The only significant difference is that i386 worked before and after this update (for y/z/a it worked neither before nor after). 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