[coreutils] [PATCH] tests: add test for parallel sort -u segfault bug

[Jim Meyering]

I've adjusted this test, and am about to push it along with Paul's patch.
It's better to derive the expected output:

diff --git a/tests/misc/sort-unique-segv b/tests/misc/sort-unique-segv
index 0a1d4cb..55a7414 100755
--- a/tests/misc/sort-unique-segv
+++ b/tests/misc/sort-unique-segv
@@ -39,15 +39,7 @@ zzzzzzzzzzz
 zzzzzzzzzzzz
 EOF

-cat <<\EOF > exp || fail=1
-
-z
-zzzzzz
-zzzzzzz
-zzzzzzzzz
-zzzzzzzzzzz
-zzzzzzzzzzzz
-EOF
+sort --parallel=1 -u in > exp || fail=1

 sort --parallel=2 -u -S 10b < in > out || fail=1
 compare out exp || fail=1


>From 3afda5f0076beca786ecbe90875828eb6988a964 Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Tue, 30 Nov 2010 22:30:12 +0100
Subject: [PATCH 1/2] sort -u: fix a thread-race pointer corruption bug

* src/sort.c (write_unique): Save the entire "struct line", not
just a pointer to one.  Otherwise, with a multi-thread run,
sometimes, with some inputs, fillbuf would would win a race
and clobber a "saved->text" pointer in one thread just before
it was dereferenced in a comparison in another thread.
* NEWS (Bug fixes): Mention it.
---
 NEWS       |    3 +++
 src/sort.c |    6 +++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index 2d3f1f3..79484c1 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,9 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   od now prints floating-point numbers without losing information, and
   it no longer omits spaces between floating-point columns in some cases.

+  sort -u with at least two threads could attempt to read through a
+  corrupted pointer. [bug introduced in coreutils-8.6]
+
 ** New features

   split accepts the --number option to generate a specific number of files.
diff --git a/src/sort.c b/src/sort.c
index 7e25f6a..1aa1eb4 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -3226,13 +3226,13 @@ queue_pop (struct merge_node_queue *queue)
 static void
 write_unique (struct line const *line, FILE *tfp, char const *temp_output)
 {
-  static struct line const *saved = NULL;
+  static struct line saved;

   if (!unique)
     write_line (line, tfp, temp_output);
-  else if (!saved || compare (line, saved))
+  else if (!saved.text || compare (line, &saved))
     {
-      saved = line;
+      saved = *line;
       write_line (line, tfp, temp_output);
     }
 }
--
1.7.3.2.846.gf4b062


>From a5207bb1391cb8e169bc6036eb036bb1a89cde89 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sun, 28 Nov 2010 12:59:38 +0100
Subject: [PATCH 2/2] tests: add test for parallel sort -u segfault bug

* tests/misc/sort-unique-segv: New file.
* tests/Makefile.am (TESTS): Add it.
---
 tests/Makefile.am           |    1 +
 tests/misc/sort-unique-segv |   47 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 0 deletions(-)
 create mode 100755 tests/misc/sort-unique-segv

diff --git a/tests/Makefile.am b/tests/Makefile.am
index b3be4df..d52f677 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -239,6 +239,7 @@ TESTS =                                             \
   misc/sort-rand                               \
   misc/sort-spinlock-abuse                     \
   misc/sort-unique                             \
+  misc/sort-unique-segv                                \
   misc/sort-version                            \
   misc/split-a                                 \
   misc/split-bchunk                            \
diff --git a/tests/misc/sort-unique-segv b/tests/misc/sort-unique-segv
new file mode 100755
index 0000000..55a7414
--- /dev/null
+++ b/tests/misc/sort-unique-segv
@@ -0,0 +1,47 @@
+#!/bin/sh
+# parallel sort with --unique (-u) would segfault
+
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+print_ver_ sort
+
+test "$(nproc)" = 1 && skip_ "requires a multi-core system"
+
+cat <<\EOF > in || framework_failure_
+
+
+
+
+
+
+
+z
+zzzzzz
+zzzzzzz
+zzzzzzz
+zzzzzzz
+zzzzzzzzz
+zzzzzzzzzzz
+zzzzzzzzzzzz
+EOF
+
+sort --parallel=1 -u in > exp || fail=1
+
+sort --parallel=2 -u -S 10b < in > out || fail=1
+compare out exp || fail=1
+
+Exit $fail
--
1.7.3.2.846.gf4b062