Re: (ITS#8013) SIGSEGV in test_filter()

[hyc@symas.com]

Leonid Yuriev wrote:
>
> 04.01.2015 02:47, Howard Chu wrote:
>> The patch is wrong. syncprov_matchops can be called twice for the same
>> operation; toggling the flag where you've placed it means the filter
>> will be incorrect on the 2nd invocation as well as on all subsequent
>> invocations.
>
> Ok, but found another case.
> The ss->s_op->ors_filter may be updated immediately after the s_mutex
> released.

Seems like the simpler fix then is to keep the mutex held until after 
test_filter finishes.
>
> This is a simple change for reproducing the bug.
>
> diff --git a/servers/slapd/overlays/syncprov.c
> b/servers/slapd/overlays/syncprov.c
> index 5ef2eaa..f579faa 100644
> --- a/servers/slapd/overlays/syncprov.c
> +++ b/servers/slapd/overlays/syncprov.c
> @@ -1295,6 +1295,7 @@ syncprov_matchops( Operation *op, opcookie *opc,
> int saveit )
>           }
>
>           if ( fc.fscope ) {
> +            Filter *paranoia;
>               ldap_pvt_thread_mutex_lock( &ss->s_mutex );
>               op2 = *ss->s_op;
>               oh = *op->o_hdr;
> @@ -1304,6 +1305,7 @@ syncprov_matchops( Operation *op, opcookie *opc,
> int saveit )
>               op2.o_hdr = &oh;
>               op2.o_extra = op->o_extra;
>               op2.o_callback = NULL;
> +            paranoia = ss->s_op->ors_filter;
>               if (ss->s_flags & PS_FIX_FILTER) {
>                   /* Skip the AND/GE clause that we stuck on in front. We
>                      would lose deletes/mods that happen during the refresh
> @@ -1311,7 +1313,11 @@ syncprov_matchops( Operation *op, opcookie *opc,
> int saveit )
>                   op2.ors_filter = ss->s_op->ors_filter->f_and->f_next;
>               }
>               ldap_pvt_thread_mutex_unlock( &ss->s_mutex );
> +            assert (paranoia == ss->s_op->ors_filter || paranoia ==
> ss->s_op->ors_filter->f_and->f_next);
> +            usleep(1000);
> +            assert (paranoia == ss->s_op->ors_filter || paranoia ==
> ss->s_op->ors_filter->f_and->f_next);
>               rc = test_filter( &op2, e, op2.ors_filter );
> +            assert (paranoia == ss->s_op->ors_filter || paranoia ==
> ss->s_op->ors_filter->f_and->f_next);
>           }
>
>           Debug( LDAP_DEBUG_TRACE, "syncprov_matchops: sid %03x fscope
> %d rc %d\n",
>
> Updated patch attached.
> Please review and merge.
>
> Leonid.
>
> ---
>
> The attached files is derived from OpenLDAP Software. All of the
> modifications
> to OpenLDAP Software represented in the following patch(es) were
> developed by
> Peter-Service LLC, Moscow, Russia. Peter-Service LLC has not assigned
> rights
> and/or interest in this work to any party. I, Leonid Yuriev am
> authorized by
> Peter-Service LLC, my employer, to release this work under the following
> terms.
>
> Peter-Service LLC hereby places the following modifications to OpenLDAP
> Software
> (and only these modifications) into the public domain. Hence, these
> modifications may be freely used and/or redistributed for any purpose
> with or without attribution and/or other notice.
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/