Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "87 patches.

  Subsystems affected by this patch series: mm (pagecache and hugetlb),
  procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs,
  init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork,
  sysvfs, kcov, gdb, resource, selftests, and ipc"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits)
  ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL
  ipc: check checkpoint_restore_ns_capable() to modify C/R proc files
  selftests/kselftest/runner/run_one(): allow running non-executable files
  virtio-mem: disallow mapping virtio-mem memory via /dev/mem
  kernel/resource: disallow access to exclusive system RAM regions
  kernel/resource: clean up and optimize iomem_is_exclusive()
  scripts/gdb: handle split debug for vmlinux
  kcov: replace local_irq_save() with a local_lock_t
  kcov: avoid enable+disable interrupts if !in_task()
  kcov: allocate per-CPU memory on the relevant node
  Documentation/kcov: define `ip' in the example
  Documentation/kcov: include types.h in the example
  sysv: use BUILD_BUG_ON instead of runtime check
  kernel/fork.c: unshare(): use swap() to make code cleaner
  seq_file: fix passing wrong private data
  seq_file: move seq_escape() to a header
  signal: remove duplicate include in signal.h
  crash_dump: remove duplicate include in crash_dump.h
  crash_dump: fix boolreturn.cocci warning
  hfs/hfsplus: use WARN_ON for sanity check
  ...

4 files changed, 102 insertions, 10 deletions

diff --git a/tools/testing/selftests/kselftest/runner.sh b/tools/testing/selftests/kselftest/runner.sh
index cc9c846585f0..a9ba782d8ca0 100644
--- a/tools/testing/selftests/kselftest/runner.sh
+++ b/tools/testing/selftests/kselftest/runner.sh
@@ -33,9 +33,9 @@ tap_timeout()
 {
 	# Make sure tests will time out if utility is available.
 	if [ -x /usr/bin/timeout ] ; then
-		/usr/bin/timeout --foreground "$kselftest_timeout" "$1"
+		/usr/bin/timeout --foreground "$kselftest_timeout" $1
 	else
-		"$1"
+		$1
 	fi
 }
 
@@ -65,17 +65,25 @@ run_one()
 
 	TEST_HDR_MSG="selftests: $DIR: $BASENAME_TEST"
 	echo "# $TEST_HDR_MSG"
-	if [ ! -x "$TEST" ]; then
-		echo -n "# Warning: file $TEST is "
-		if [ ! -e "$TEST" ]; then
-			echo "missing!"
-		else
-			echo "not executable, correct this."
-		fi
+	if [ ! -e "$TEST" ]; then
+		echo "# Warning: file $TEST is missing!"
 		echo "not ok $test_num $TEST_HDR_MSG"
 	else
+		cmd="./$BASENAME_TEST"
+		if [ ! -x "$TEST" ]; then
+			echo "# Warning: file $TEST is not executable"
+
+			if [ $(head -n 1 "$TEST" | cut -c -2) = "#!" ]
+			then
+				interpreter=$(head -n 1 "$TEST" | cut -c 3-)
+				cmd="$interpreter ./$BASENAME_TEST"
+			else
+				echo "not ok $test_num $TEST_HDR_MSG"
+				return
+			fi
+		fi
 		cd `dirname $TEST` > /dev/null
-		((((( tap_timeout ./$BASENAME_TEST 2>&1; echo $? >&3) |
+		((((( tap_timeout "$cmd" 2>&1; echo $? >&3) |
 			tap_prefix >&4) 3>&1) |
 			(read xs; exit $xs)) 4>>"$logfile" &&
 		echo "ok $test_num $TEST_HDR_MSG") ||
diff --git a/tools/testing/selftests/proc/.gitignore b/tools/testing/selftests/proc/.gitignore
index 8f3e72e626fa..c4e6a34f9657 100644
--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -11,6 +11,7 @@
 /proc-self-syscall
 /proc-self-wchan
 /proc-subset-pid
+/proc-tid0
 /proc-uptime-001
 /proc-uptime-002
 /read
diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index 1054e40a499a..219fc6113847 100644
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 CFLAGS += -Wall -O2 -Wno-unused-function
 CFLAGS += -D_GNU_SOURCE
+LDFLAGS += -pthread
 
 TEST_GEN_PROGS :=
 TEST_GEN_PROGS += fd-001-lookup
@@ -13,6 +14,7 @@ TEST_GEN_PROGS += proc-self-map-files-002
 TEST_GEN_PROGS += proc-self-syscall
 TEST_GEN_PROGS += proc-self-wchan
 TEST_GEN_PROGS += proc-subset-pid
+TEST_GEN_PROGS += proc-tid0
 TEST_GEN_PROGS += proc-uptime-001
 TEST_GEN_PROGS += proc-uptime-002
 TEST_GEN_PROGS += read
diff --git a/tools/testing/selftests/proc/proc-tid0.c b/tools/testing/selftests/proc/proc-tid0.c
new file mode 100644
index 000000000000..58c1d7c90a8e
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-tid0.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+// Test that /proc/*/task never contains "0".
+#include <sys/types.h>
+#include <dirent.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <pthread.h>
+
+static pid_t pid = -1;
+
+static void atexit_hook(void)
+{
+	if (pid > 0) {
+		kill(pid, SIGKILL);
+	}
+}
+
+static void *f(void *_)
+{
+	return NULL;
+}
+
+static void sigalrm(int _)
+{
+	exit(0);
+}
+
+int main(void)
+{
+	pid = fork();
+	if (pid == 0) {
+		/* child */
+		while (1) {
+			pthread_t pth;
+			pthread_create(&pth, NULL, f, NULL);
+			pthread_join(pth, NULL);
+		}
+	} else if (pid > 0) {
+		/* parent */
+		atexit(atexit_hook);
+
+		char buf[64];
+		snprintf(buf, sizeof(buf), "/proc/%u/task", pid);
+
+		signal(SIGALRM, sigalrm);
+		alarm(1);
+
+		while (1) {
+			DIR *d = opendir(buf);
+			struct dirent *de;
+			while ((de = readdir(d))) {
+				if (strcmp(de->d_name, "0") == 0) {
+					exit(1);
+				}
+			}
+			closedir(d);
+		}
+
+		return 0;
+	} else {
+		perror("fork");
+		return 1;
+	}
+}