[PATCH 0/3] Miscellaneous RCU updates for v6.19

[PATCH 0/3] Miscellaneous RCU updates for v6.19

[Paul E. McKenney]

Hello!

This series provides miscellaneous RCU updates:

1.	Fix memory leak in param_set_cpumask(), courtesy of Wang Liang.

2.	use WRITE_ONCE() for ->next and ->pprev of hlist_nulls, courtesy
	of Xuanqiang Luo.

3.	Add kvm-series.sh to test commit/scenario combination.

						Thanx, Paul

------------------------------------------------------------------------

 include/linux/rculist_nulls.h                        |    6 
 kernel/locking/locktorture.c                         |    8 -
 tools/testing/selftests/rcutorture/bin/kvm-series.sh |  115 +++++++++++++++++++
 3 files changed, 124 insertions(+), 5 deletions(-)

[PATCH 1/3] locktorture: Fix memory leak in param_set_cpumask()

[Paul E. McKenney]

From: Wang Liang <wangliang74@huawei.com>

With CONFIG_CPUMASK_OFFSTACK=y, the 'bind_writers' buffer is allocated via
alloc_cpumask_var() in param_set_cpumask(). But it is not freed, when
setting the module parameter multiple times by sysfs interface or removing
module.

Below kmemleak trace is seen for this issue:

unreferenced object 0xffff888100aabff8 (size 8):
  comm "bash", pid 323, jiffies 4295059233
  hex dump (first 8 bytes):
    07 00 00 00 00 00 00 00                          ........
  backtrace (crc ac50919):
    __kmalloc_node_noprof+0x2e5/0x420
    alloc_cpumask_var_node+0x1f/0x30
    param_set_cpumask+0x26/0xb0 [locktorture]
    param_attr_store+0x93/0x100
    module_attr_store+0x1b/0x30
    kernfs_fop_write_iter+0x114/0x1b0
    vfs_write+0x300/0x410
    ksys_write+0x60/0xd0
    do_syscall_64+0xa4/0x260
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

This issue can be reproduced by:
  insmod locktorture.ko bind_writers=1
  rmmod locktorture

or:
  insmod locktorture.ko bind_writers=1
  echo 2 > /sys/module/locktorture/parameters/bind_writers

Considering that setting the module parameter 'bind_writers' or
'bind_readers' by sysfs interface has no real effect, set the parameter
permissions to 0444. To fix the memory leak when removing module, free
'bind_writers' and 'bind_readers' memory in lock_torture_cleanup().

Fixes: 73e341242483 ("locktorture: Add readers_bind and writers_bind module parameters")
Suggested-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: Wang Liang <wangliang74@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/locking/locktorture.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index ce0362f0a871..6567e5eeacc0 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -103,8 +103,8 @@ static const struct kernel_param_ops lt_bind_ops = {
 	.get = param_get_cpumask,
 };
 
-module_param_cb(bind_readers, &lt_bind_ops, &bind_readers, 0644);
-module_param_cb(bind_writers, &lt_bind_ops, &bind_writers, 0644);
+module_param_cb(bind_readers, &lt_bind_ops, &bind_readers, 0444);
+module_param_cb(bind_writers, &lt_bind_ops, &bind_writers, 0444);
 
 long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn);
 
@@ -1211,6 +1211,10 @@ static void lock_torture_cleanup(void)
 			cxt.cur_ops->exit();
 		cxt.init_called = false;
 	}
+
+	free_cpumask_var(bind_readers);
+	free_cpumask_var(bind_writers);
+
 	torture_cleanup_end();
 }
 
-- 
2.40.1

[PATCH 2/3] rcu: use WRITE_ONCE() for ->next and ->pprev of hlist_nulls

[Paul E. McKenney]

From: Xuanqiang Luo <luoxuanqiang@kylinos.cn>

In rculist_nulls.h we can still see ordinary assignments to ->pprev and
->next of hlist_nulls.

As noted in the two patches below:
commit efd04f8a8b45 ("rcu: Use WRITE_ONCE() for assignments to ->next for
rculist_nulls")
commit 860c8802ace1 ("rcu: Use WRITE_ONCE() for assignments to ->pprev for
hlist_nulls")

We should use WRITE_ONCE().

Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 include/linux/rculist_nulls.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
index 89186c499dd4..d5a656cc4c6a 100644
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -138,7 +138,7 @@ static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
 
 	if (last) {
 		WRITE_ONCE(n->next, last->next);
-		n->pprev = &last->next;
+		WRITE_ONCE(n->pprev, &last->next);
 		rcu_assign_pointer(hlist_nulls_next_rcu(last), n);
 	} else {
 		hlist_nulls_add_head_rcu(n, h);
@@ -148,8 +148,8 @@ static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
 /* after that hlist_nulls_del will work */
 static inline void hlist_nulls_add_fake(struct hlist_nulls_node *n)
 {
-	n->pprev = &n->next;
-	n->next = (struct hlist_nulls_node *)NULLS_MARKER(NULL);
+	WRITE_ONCE(n->pprev, &n->next);
+	WRITE_ONCE(n->next, (struct hlist_nulls_node *)NULLS_MARKER(NULL));
 }
 
 /**
-- 
2.40.1

[PATCH 3/3] torture: Add kvm-series.sh to test commit/scenario combination

[Paul E. McKenney]

This commit adds a kvm-series.sh script that takes a list of scenarios and
a list of commits, and then runs each scenario on all of the commits.
A given scenario is run on all the commits before advancing to the
next scenario to minimize build times.  The successes and failures are
summarized at the end of the run.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 .../selftests/rcutorture/bin/kvm-series.sh    | 115 ++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100755 tools/testing/selftests/rcutorture/bin/kvm-series.sh

diff --git a/tools/testing/selftests/rcutorture/bin/kvm-series.sh b/tools/testing/selftests/rcutorture/bin/kvm-series.sh
new file mode 100755
index 000000000000..a39e401c8d4d
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/kvm-series.sh
@@ -0,0 +1,115 @@
+#!/bin/bash
+#
+# Usage: kvm-series.sh config-list commit-id-list [ kvm.sh parameters ]
+#
+# Tests the specified list of unadorned configs ("TREE01 SRCU-P" but not
+# "CFLIST" or "3*TRACE01") and an indication of a set of commits to test,
+# then runs each commit through the specified list of commits using kvm.sh.
+# The runs are grouped into a -series/config/commit directory tree.
+# Each run defaults to a duration of one minute.
+# 
+# Run in top-level Linux source directory.  Please note that this is in
+# no way a replacement for "git bisect"!!!
+#
+# This script is intended to replace kvm-check-branches.sh by providing
+# ease of use and faster execution.
+
+T="`mktemp -d ${TMPDIR-/tmp}/kvm-series.sh.XXXXXX`"
+trap 'rm -rf $T' 0
+
+scriptname=$0
+args="$*"
+
+config_list="${1}"
+if test -z "${config_list}"
+then
+	echo "$0: Need a quoted list of --config arguments for first argument."
+	exit 1
+fi
+if test -z "${config_list}" || echo "${config_list}" | grep -q '\*'
+then
+	echo "$0: Repetition ('*') not allowed in config list."
+	exit 1
+fi
+
+commit_list="${2}"
+if test -z "${commit_list}"
+then
+	echo "$0: Need a list of commits (e.g., HEAD^^^..) for second argument."
+	exit 2
+fi
+git log --pretty=format:"%h" "${commit_list}" > $T/commits
+ret=$?
+if test "${ret}" -ne 0
+then
+	echo "$0: Invalid commit list ('${commit_list}')."
+	exit 2
+fi
+sha1_list=`cat $T/commits`
+
+shift
+shift
+
+RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
+PATH=${RCUTORTURE}/bin:$PATH; export PATH
+. functions.sh
+
+ret=0
+nfail=0
+nsuccess=0
+faillist=
+successlist=
+cursha1="`git rev-parse --abbrev-ref HEAD`"
+ds="`date +%Y.%m.%d-%H.%M.%S`-series"
+startdate="`date`"
+starttime="`get_starttime`"
+
+echo " --- " $scriptname $args | tee -a $T/log
+echo " --- Results directory: " $ds | tee -a $T/log
+
+for config in ${config_list}
+do
+	sha_n=0
+	for sha in ${sha1_list}
+	do
+		sha1=${sha_n}.${sha} # Enable "sort -k1nr" to list commits in order.
+		echo Starting ${config}/${sha1} at `date` | tee -a $T/log
+		git checkout "${sha}"
+		time tools/testing/selftests/rcutorture/bin/kvm.sh --configs "$config" --datestamp "$ds/${config}/${sha1}" --duration 1 "$@"
+		curret=$?
+		if test "${curret}" -ne 0
+		then
+			nfail=$((nfail+1))
+			faillist="$faillist ${config}/${sha1}(${curret})"
+		else
+			nsuccess=$((nsuccess+1))
+			successlist="$successlist ${config}/${sha1}"
+			# Successful run, so remove large files.
+			rm -f ${RCUTORTURE}/$ds/${config}/${sha1}/{vmlinux,bzImage,System.map,Module.symvers}
+		fi
+		if test "${ret}" -eq 0
+		then
+			ret=${curret}
+		fi
+		sha_n=$((sha_n+1))
+	done
+done
+git checkout "${cursha1}"
+
+echo ${nsuccess} SUCCESSES: | tee -a $T/log
+echo ${successlist} | fmt | tee -a $T/log
+echo | tee -a $T/log
+echo ${nfail} FAILURES: | tee -a $T/log
+echo ${faillist} | fmt | tee -a $T/log
+if test -n "${faillist}"
+then
+	echo | tee -a $T/log
+	echo Failures across commits: | tee -a $T/log
+	echo ${faillist} | tr ' ' '\012' | sed -e 's,^[^/]*/,,' -e 's/([0-9]*)//' |
+		sort | uniq -c | sort -k2n | tee -a $T/log
+fi
+echo Started at $startdate, ended at `date`, duration `get_starttime_duration $starttime`. | tee -a $T/log
+echo Summary: Successes: ${nsuccess} Failures: ${nfail} | tee -a $T/log
+cp $T/log tools/testing/selftests/rcutorture/res/${ds}
+
+exit "${ret}"
-- 
2.40.1