On 10/03/2016 04:34 PM, AKASHI Takahiro wrote: > 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 I am saying it that If the first kernel is booted using mem= option and crashkernel= option the memory for second kernel has to be withing the crashkernel size. As per /proc/iomem System RAM the information is correct, but the /proc/meminfo is showing total memory much more than the first kernel had in first place. > What about if you don't specify "crashkernel=...?" > In that case the second kernel will not boot as kexec tools will complain that memory not reserved. >> 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. If I run with debug logs phys address accessed is > 64G. (10413ffcc0) Could be that somehow 64 + 1G + (addr) = 10413ffcc0 and actually addr was required. addr = 413ffcc0 which seems in line with 424b0c50 Logs: <read_dev_mem: addr: ffff0000090b3008 paddr: 424b3008 cnt: 8> node_online_map: [1] -> nodes online: 1 <readmem: ffff0000090b0c50, KVADDR, ""node_data"", 8, (ROE), ffffc330eb00> <read_dev_mem: addr: ffff0000090b0c50 paddr: 424b0c50 cnt: 8> <readmem: ffff800ffffffcc0, KVADDR, ""pglist node_id"", 4, (FOE), ffffc330f1e4> <read_dev_mem: addr: ffff800ffffffcc0 paddr: 10413ffcc0 cnt: 4> /dev/mem: Bad address crash: read(/dev/mem, 10413ffcc0, 4): 4294967295 (ffffffff) crash: read error: kernel virtual address: ffff800ffffffcc0 type: ""pglist node_id"" " > >> 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?" > 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. The same patch as below ? Can you please share your 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 >>
