Dataflow causes crash when THRnew fails

[monetdb-team]

Date: 2018-07-31 13:25:32 +0200
From: @yzchang
To: MonetDB5 devs <>
Version: 11.29.3 (Mar2018)

Last updated: 2018-08-31 13:23:23 +0200

Comment 26575

Date: 2018-07-31 13:25:32 +0200
From: @yzchang

In DFLOWworker(), the return value of "thr = THRnew("DFLOWworker");" is not checked. So, if THRnew() failed (e.g. too many threads already), DFLOWworker() will trigger a SIGSEGV when thr is used.

In general, there are 6 places where THRnew is used:

$ grep -r =.*THRnew *
monetdb5/modules/mal/tablet.c: thr = THRnew("SQLworker");
monetdb5/modules/mal/tablet.c: thr = THRnew("SQLproducer");
monetdb5/mal/mal_client.c: t = THRnew(cname);
monetdb5/mal/mal_dataflow.c: thr = THRnew("DFLOWworker");
sql/server/sql_mvc.c: Thread thr = THRnew("logmanager");
sql/server/sql_mvc.c: Thread thr = THRnew("idlemanager");

Only in mal_client.c, the return value is checked.

Comment 26576

Date: 2018-08-01 10:12:32 +0200
From: MonetDB Mercurial Repository <>

Changeset 7f7bdde7c0d6 made by Sjoerd Mullender sjoerd@acm.org in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=7f7bdde7c0d6

Changeset description:

Check THRnew result.
This should fix bug #6632.

Comment 26577

Date: 2018-08-01 12:29:33 +0200
From: @sjoerdmullender

The changesets 7f7bdde7c0d6 2b373f2e74f3 and 709ebc975d62 together fix this issue. All THRnew calls are now checked.

Comment 26578

Date: 2018-08-01 12:55:03 +0200
From: MonetDB Mercurial Repository <>

Changeset 0d3f2de0372f made by Sjoerd Mullender sjoerd@acm.org in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=0d3f2de0372f

Changeset description:

Check THRnew result.
This should fix bug #6632.
(grafted from 7f7bdde7c0d6b9b4176030d3fc68dacf2e959b63)