Manish, On Mon, Oct 03, 2016 at 01:24:34PM +0530, Manish Jaggi wrote: > Hi Akashi, > > On 09/07/2016 09:59 AM, AKASHI Takahiro wrote: > > v26-specific note: After a comment from Rob[0], an idea of adding > > "linux,usable-memory-range" was dropped. Instead, an existing > > "reserved-memory" node will be used to limit usable memory ranges > > on crash dump kernel. > > This works not only on UEFI/ACPI systems but also on DT-only systems, > > but if he really insists on using DT-specific "usable-memory" property, > > I will post additional patches for kexec-tools. Those would be > > redundant, though. > > Even in that case, the kernel will not have to be changed. > > > > This patch series adds kdump support on arm64. > > There are some prerequisite patches [1],[2]. > > > > To load a crash-dump kernel to the systems, a series of patches to > > kexec-tools, which have not yet been merged upstream, are needed. > > Please always use my latest kdump patches, v3 [3]. > > > > To examine vmcore (/proc/vmcore) on a crash-dump kernel, you can use > > - crash utility (coming v7.1.6 or later) [4] > > (Necessary patches have already been queued in the master.) > > > > > > [0] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/452582.html > > [1] "arm64: mark reserved memblock regions explicitly in iomem" > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/450433.html > > [2] "efi: arm64: treat regions with WT/WC set but WB cleared as memory" > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/451491.html > > [3] T.B.D. > > [4] https://github.com/crash-utility/crash.git > > > > With the v26 kdump and v3 kexec-tools and top of tree crash.git, below are the tests done > Attached is a patch in crash.git (symbols.c) to make crash utility work on my setup. > Can you please have a look and provide your comments. > > To generate a panic, i have a kernel module which on init calls panic. > > Observations: > 1.1. Dump capture kernel shows different memory map. > --------------------------------------------------- > In dump capture kernel /proc/meminfo and /proc/iomem differ > > root at arm64:/home/ubuntu/CODE/crash# > MemTotal: 65882432 kB > MemFree: 65507136 kB > MemAvailable: 60373632 kB > Buffers: 29248 kB > Cached: 46720 kB > SwapCached: 0 kB > Active: 63872 kB > Inactive: 19776 kB > Active(anon): 8256 kB > Inactive(anon): 7616 kB > > First kernel is booted with mem=2G crashkernel=1G command line option. > While the system has 64G memory. > > root at arm64:/home/ubuntu/CODE/crash# cat /proc/iomem > 41400000-fffeffff : System RAM > 41480000-420cffff : Kernel code > 42490000-4278ffff : Kernel data > ffff0000-ffffffff : reserved > 100000000-ffaa7ffff : System RAM > ffaa80000-ffaabffff : reserved > ffaac0000-fffa6ffff : System RAM > fffa70000-fffacffff : reserved > fffad0000-fffffffff : System RAM Are you saying that "mem=..." doesn't have any effect? What about if you don't specify "crashkernel=...?" > 1.2 Live crash dump fails with error > -------------------------------------- > $crash vmlinux > > crash 7.1.5++ > 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"... > > crash: read error: kernel virtual address: ffff800ffffffcc0 type: "pglist node_id" I have no ideas here. > Observation 2 > ------------ > If saved vmcore file is used > > $crash vmlinux vmcore_saved > Got the below error. > > please wait... (gathering module symbol data)crash: malloc.c:2846: mremap_chunk: Assertion `((size + offset) & (_rtld_global_ro._dl_pagesize - 1)) == 0' failed. > Aborted I have no ideas here. > Experiment 3 > ------------ > If crash.git is modified with a hack patch in symbols.c. Crash utility works fine log, bt commands work. In which case, "crash vmlinux" or "crash vmlinux vmcore_saved?" I was able to reproduce this issue in the latter case (but with a different error message). It seems to be a crash util's bug. Please report it to crash-util mailing list. I will post a patch. Thanks, -Takahiro AKASHI > ------------------- > Patch: symbols.c > git diff symbols.c > diff --git a/symbols.c b/symbols.c > index 13282f4..f7c6cac 100644 > --- a/symbols.c > +++ b/symbols.c > @@ -2160,6 +2160,7 @@ store_module_kallsyms_v2(struct load_module *lm, int start > FREEBUF(module_buf); > return 0; > } > + lm->mod_init_size = 0; > > if (lm->mod_init_size > 0) { > module_buf_init = GETBUF(lm->mod_init_size); > ------------------ > > $ crash vmlinux vmcore_saved > KERNEL: /home/ubuntu/CODE/linux/vmlinux > DUMPFILE: vm > CPUS: 48 [OFFLINE: 46] > DATE: Mon Oct 3 00:11:47 2016 > UPTIME: 00:02:41 > LOAD AVERAGE: 0.36, 0.14, 0.05 > TASKS: 171 > NODENAME: arm64 > RELEASE: 4.8.0-rc3-00044-g070a615-dirty > VERSION: #63 SMP Sat Oct 1 01:39:45 PDT 2016 > MACHINE: aarch64 (unknown Mhz) > MEMORY: 2 GB > PANIC: "Kernel panic - not syncing: crash module starting" > PID: 958 > COMMAND: "insmod" > TASK: ffff800007859300 [THREAD_INFO: ffff80000c940000] > CPU: 0 > STATE: TASK_RUNNING (PANIC) > > crash> bt > PID: 958 TASK: ffff800007859300 CPU: 0 COMMAND: "insmod" > #0 [ffff80000c943980] __crash_kexec at ffff000008144fe8 > #1 [ffff80000c943ae0] panic at ffff0000081ae704 > #2 [ffff80000c943ba0] init_module at ffff000000900014 [crash] > #3 [ffff80000c943bb0] do_one_initcall at ffff000008083bb4 > #4 [ffff80000c943c40] do_init_module at ffff0000081af6f0 > #5 [ffff80000c943c70] load_module at ffff000008140b7c > #6 [ffff80000c943e10] sys_finit_module at ffff000008141634 > #7 [ffff80000c943ed0] el0_svc_naked at ffff0000080833ec > PC: 00000003 LR: ffffaca050a0 SP: ffffaca865a0 PSTATE: 00000111 > X12: ffffac941a5c X11: 00000080 X10: 00000004 X9: 00000030 > X8: ffffffff X7: fefefefefefeff40 X6: 00000111 X5: 00000001 > X4: 00000001 X3: 0002ed61 X2: 00000000 X1: 00000003 > X0: 00000000 > crash> > > > --- > Thanks, > manish >
