Re: [Crash-utility] EXT: RE: crash: read error on type: "memory section root table"
On 2022/07/22 21:04, Agrain Patrick wrote:
Hello,
Back to this topic.
I upgraded our system with the kexec-tools from Centos 8 Stream, based on kexec 2.0.24
and makedumpfile 1.7.1.
We are still facing errors when using 'makedumpfile -c'.
Removing the '-c' gives better ratio success/failure, but sometimes the crash
file cannot be read by the crash tool.
Referring to Hagio's remark below concerning the sync, I added a sync operation
before the call of makedumpfile (and just after the mount ext4 of the required partitions)
and add a second call to sync after the return of makedumpfile.
In that configuration, the crash file can be read by the crash tool (up to now in all
cases).
Good, seems the second sync works. I would suggest unmounting the filesystem
cleanly, which contains syncing to disk, before reboot, if you don't do that.
Thanks,
Kazu
>
> Thanks for your help.
> Best regards,
> Patrick Agrain
>
> -----Message d'origine-----
> De : Crash-utility <crash-utility-bounces(a)redhat.com> De la part de Agrain
Patrick
> Envoyé : mercredi 6 avril 2022 17:48
> À : Discussion list for crash utility usage, maintenance and development
<crash-utility(a)redhat.com>; kexec(a)lists.infradead.org
> Objet : Re: [Crash-utility] EXT: RE: crash: read error on type: "memory section
root table"
>
>
>
> -----Message d'origine-----
> De : HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com> Envoyé : mercredi 6 avril 2022
09:48 À : Agrain Patrick <patrick.agrain(a)al-enterprise.com>
> Cc : Discussion list for crash utility usage, maintenance and development
<crash-utility(a)redhat.com>; kexec(a)lists.infradead.org Objet : RE: EXT: RE: crash:
read error on type: "memory section root table"
>
> -----Original Message-----
>> Hello,
>>
>> Suggested trace above gives following information after a crash -d 8 command:
>> <...>
>> kernel NR_CPUS: 2
>> <readmem: ffffffffa4925820, KVADDR, "high_memory", 8, (FOE),
>> 56017b542648>
>> <read_diskdump: addr: ffffffffa4925820 paddr: 12925820 cnt: 8>
>> read_diskdump: paddr/pfn: 12925820/12925 -> cache physical page:
>> 12925000
>> GETBUF(328 -> 0)
>> FREEBUF(0)
>> GETBUF(328 -> 0)
>> FREEBUF(0)
>> PAGESIZE=4096
>> mem_section_size = 16384
>> NR_SECTION_ROOTS = 2048
>> NR_MEM_SECTIONS = 524288
>> SECTIONS_PER_ROOT = 256
>> SECTION_ROOT_MASK = 0xff
>> PAGES_PER_SECTION = 32768
>> <readmem: ffffffffa4926db0, KVADDR, "mem_section", 8, (FOE),
>> 7ffd1b6bb000>
>> <read_diskdump: addr: ffffffffa4926db0 paddr: 12926db0 cnt: 8>
>> read_diskdump: paddr/pfn: 12926db0/12926 -> cache physical page:
>> 12926000
>> <readmem: ffff904c7f7fc000, KVADDR, "memory section root table",
>> 16384, (FOE), 56017da26fd0>
>> <read_diskdump: addr: ffff904c7f7fc000 paddr: 3f7fc000 cnt: 4096>
>> read_diskdump: paddr/pfn: 3f7fc000/3f7fc -> cache physical page:
>> 3f7fc000
>> crash: PAG3 - errno=2 r=0 pd.size=49
>> read_diskdump: READ_ERROR: cannot cache page: 3f7fc000
>> crash: read error: kernel virtual address: ffff904c7f7fc000 type: "memory
section root table"
>
> hmm, r=0 means end of file, can you check again whether pd.offset exceeds the
dumpfile size? If so, somehow the dumpfile is shorter than expected.
>
> Indeed, the offset points outside the dumpfile:
> Get:
> crash: PAG3 - errno=2 r=0 pd.size=52 pd.offset=168956485 with a dumpfile
> 164820 -rw-r--r--. 1 root root 168775680 6 avril 17:23 crashdump--20220406-1713
>
> And another one:
> Get:
> crash: PAG3 - errno=2 r=0 pd.size=49 pd.offset=215640649 with a dumpfile
> 209984 -rw-r--r--. 1 root root 215023616 1 avril 10:58
crashdump-585.000-20220401-1054
>
> I think a RHEL-based kexec-tools does "sync" after makedumpfile, but can
you check?
>
> Actually, we are executing the makedumpfile in a script designated as init file for
the second kernel. Therefore, we do not perform the sync as per core_collector.
>
> Thanks,
> Kazu
>
> Best regards,
> Patrick
>
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