Finding cause of 389ds sefault crash

[Nelson Bartley]

Good afternoon

Our ns-slapd crashed earlier today, with a segfault in libback-ldbm.so
while the system was running a bdb_db_compact_one_db action.

Is there anyway to trackdown/diagnose what might have caused the
segfault? Some type of DB integrity check or something?

Nelson

[thierry bordaz]

Hi,

By any chance do you know if the crash (SIGSEV) dumped a core ?
In such case you may install debuginfo rpm and analyze (gdb) the reason 
of the crash.

I am not sure the crash is due to a DB corruption/breakage but clearly 
the crash will trigger a recovery.
Is the suffix (userRoot) replicated ? is it a supplier or a hub ?
I have the feeling it crashed while compacting the changelog. 
bdb_db_compact_one_db is possibly missing a test that the 'db' 
(changelog) exists before dereferencing it.

regards
thierry

On 3/18/21 8:08 AM, Nelson Bartley wrote:
>  Good afternoon
>
>  Our ns-slapd crashed earlier today, with a segfault in libback-ldbm.so
>  while the system was running a bdb_db_compact_one_db action.
>
>  Is there anyway to trackdown/diagnose what might have caused the
>  segfault? Some type of DB integrity check or something?
>
>  Nelson
>
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[William Brown]

>  On 18 Mar 2021, at 18:46, thierry bordaz <tbordaz(a)redhat.com&gt;
> wrote:
>  
>  Hi,
>  
>  By any chance do you know if the crash (SIGSEV) dumped a core ?
>  In such case you may install debuginfo rpm and analyze (gdb) the reason of the crash.
>  
>  I am not sure the crash is due to a DB corruption/breakage but clearly the crash will
> trigger a recovery.
>  Is the suffix (userRoot) replicated ? is it a supplier or a hub ?
>  I have the feeling it crashed while compacting the changelog. bdb_db_compact_one_db is
> possibly missing a test that the 'db' (changelog) exists before dereferencing it.
Could be worth adding a log message and an ASSERT here so that we can catch this case if
it's happening ... .

>  
>  regards
>  thierry 
>  
>  On 3/18/21 8:08 AM, Nelson Bartley wrote:
> > Good afternoon
> > 
> > Our ns-slapd crashed earlier today, with a segfault in libback-ldbm.so
> > while the system was running a bdb_db_compact_one_db action.
> > 
> > Is there anyway to trackdown/diagnose what might have caused the
> > segfault? Some type of DB integrity check or something?
> > 
> > Nelson
> > 
> > 
> > 
> > _______________________________________________
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> > 389-users(a)lists.fedoraproject.org
> > 
> > To unsubscribe send an email to 
> > 389-users-leave(a)lists.fedoraproject.org
> > 
> > Fedora Code of Conduct: 
> > https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> > 
> > List Guidelines: 
> > https://fedoraproject.org/wiki/Mailing_list_guidelines
> > 
> > List Archives: 
> > https://lists.fedoraproject.org/archives/list/[e-mail]...
> > 
> > Do not reply to spam on the list, report it: 
> > https://pagure.io/fedora-infrastructure
>  
>  _______________________________________________
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>  To unsubscribe send an email to 389-users-leave(a)lists.fedoraproject.org
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—
Sincerely,

William Brown

Senior Software Engineer, 389 Directory Server
SUSE Labs, Australia