|Summary:||The DUMPFILE field of vmcore showing "vmcore [PARTIAL DUMP]"|
|Product:||Red Hat Enterprise Linux 6||Reporter:||Anil <dhaneshwar_anil>|
|Component:||crash||Assignee:||Dave Anderson <anderson>|
|Status:||CLOSED NOTABUG||QA Contact:||Red Hat Kernel QE team <kernel-qe>|
|Fixed In Version:||Doc Type:||Bug Fix|
|Doc Text:||Story Points:||---|
|Last Closed:||2012-09-13 17:28:05 UTC||Type:||Bug|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
|Cloudforms Team:||---||Target Upstream Version:|
Description Anil 2012-09-13 15:20:37 UTC
Description of problem: The DUMPFILE field of vmcore showing "vmcore [PARTIAL DUMP]" on RHEL6_U3. Output from vmcore file ======================== KERNEL: ../vmlinux DUMPFILE: vmcore [PARTIAL DUMP] CPUS: 4 DATE: Thu Sep 6 00:41:02 2012 UPTIME: 13:53:20 LOAD AVERAGE: 302.68, 302.26, 300.01 TASKS: 997 NODENAME: rhel6_u3 RELEASE: 2.6.32-279.el6.x86_64 VERSION: #1 SMP Wed Jun 13 18:24:36 EDT 2012 MACHINE: x86_64 (2000 Mhz) MEMORY: 8 GB PANIC: "Kernel panic" PID: 10536 COMMAND: "umount" TASK: ffff88011e8ff500 [THREAD_INFO: ffff88004681c000] CPU: 0 STATE: TASK_RUNNING (PANIC) How reproducible: Steps to Reproduce: 1.generate the vmcore by cmd "echo c > /proc/sysrq-trigger" 2.read this vmcore using crash 3.DUMPFILE field will show "DUMPFILE: vmcore [PARTIAL DUMP]" Is the meaning of [PARTIAL DUMP] means we havent got the full dump? can I do my investigation on this dump? Also suggest if I miss any setting to take k-dump. Thanks !!!
Comment 2 Dave Anderson 2012-09-13 17:25:30 UTC
> 1.generate the vmcore by cmd "echo c > /proc/sysrq-trigger" > 2.read this vmcore using crash > 3.DUMPFILE field will show "DUMPFILE: vmcore [PARTIAL DUMP]" > > Is the meaning of [PARTIAL DUMP] means we havent got the full dump? > can I do my investigation on this dump? > > Also suggest if I miss any setting to take k-dump The system that crashed has been configured such that the vmcore is filtered by the makedumpfile facility to remove unnecessary pages. Check the crashed system's /etc/kdump.conf file. It probably has a line that configures "core_collector" to something like this: core_collector makedumpfile -c --message-level 1 -d 31 The -c means "compressed" and the "-d <number>" is a bitmask that allows you to filter out zero-filled pages, page-cache pages, user-program pages, and free-pages. This is the relevant section from "makedumpfile --help": [-d DL]: Specify the type of unnecessary page for analysis. Pages of the specified type are not copied to DUMPFILE. The page type marked in the following table is excluded. A user can specify multiple page types by setting the sum of each page type for Dump_Level (DL). The maximum of Dump_Level is 31. Note that Dump_Level for Xen dump filtering is 0 or 1. Dump | zero cache cache user free Level | page page private data page -------+--------------------------------------- 0 | 1 | X 2 | X 4 | X X 8 | X 16 | X 31 | X X X X X If your configuration also uses "-c" to make the vmcore file a compressed dumpfile, you can use the crash utility itself to access the dump-level value, like this example where -d31 was used: crash> help -n | grep dump_level dump_level: 31 (0x1f) (DUMP_EXCLUDE_ZERO|DUMP_EXCLUDE_CACHE|DUMP_EXCLUDE_CACHE_PRI|DUMP_EXCLUDE_USER_DATA|DUMP_EXCLUDE_FREE) crash> If "-c" was not used, then you would have to consult the /etc/kdump.conf file on the crashed machine to see how it was configured. In any case, it's highly unlikely that the contents of any of the filterable page-types above are necessary to investigate the cause of a kernel crash.