Add regression test for patch "block/loop: Use global lock for ioctl()
operation." where we can oops while traversing list of loop devices
backing newly created device.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
src/Makefile | 3 ++-
src/loop_change_fd.c | 48 +++++++++++++++++++++++++++++++++
tests/loop/007 | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++
tests/loop/007.out | 2 ++
4 files changed, 127 insertions(+), 1 deletion(-)
create mode 100644 src/loop_change_fd.c
create mode 100755 tests/loop/007
create mode 100644 tests/loop/007.out
diff --git a/src/Makefile b/src/Makefile
index 6dadcbec8beb..acd169718b7d 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -5,7 +5,8 @@ C_TARGETS := \
sg/dxfer-from-dev \
sg/syzkaller1 \
nbdsetsize \
- loop_set_status_partscan
+ loop_set_status_partscan \
+ loop_change_fd
CXX_TARGETS := \
discontiguous-io
diff --git a/src/loop_change_fd.c b/src/loop_change_fd.c
new file mode 100644
index 000000000000..b124d829f380
--- /dev/null
+++ b/src/loop_change_fd.c
@@ -0,0 +1,48 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <linux/loop.h>
+
+void usage(const char *progname)
+{
+ fprintf(stderr, "usage: %s LOOPDEV PATH\n", progname);
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+ int ret;
+ int fd, filefd;
+
+ if (argc != 3)
+ usage(argv[0]);
+
+ fd = open(argv[1], O_RDWR);
+ if (fd == -1) {
+ perror("open");
+ return EXIT_FAILURE;
+ }
+
+ filefd = open(argv[2], O_RDWR);
+ if (filefd == -1) {
+ perror("open");
+ return EXIT_FAILURE;
+ }
+
+ ret = ioctl(fd, LOOP_CHANGE_FD, filefd);
+ if (ret == -1) {
+ perror("ioctl");
+ close(fd);
+ close(filefd);
+ return EXIT_FAILURE;
+ }
+ close(fd);
+ close(filefd);
+ return EXIT_SUCCESS;
+}
diff --git a/tests/loop/007 b/tests/loop/007
new file mode 100755
index 000000000000..98e4edbe7afa
--- /dev/null
+++ b/tests/loop/007
@@ -0,0 +1,75 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2018 Jan Kara
+#
+# Regression test for patch "block/loop: Use global lock for ioctl() operation."
+# We swap file (through LOOP_CHANGE_FD) under one loopback device while
+# creating and deleting another loopback device pointing to the first one.
+# This checks for races in validation of backing fd.
+
+. tests/loop/rc
+
+DESCRIPTION="check for crash when validating new loop file"
+
+# Try for some time to trigger the race
+TIMED=1
+
+requires() {
+ _have_src_program loop_change_fd
+}
+
+# Setup and tear down loop device pointing to loop_dev
+run_setter() {
+ loop_dev="$1"
+
+ while top_dev=$(losetup -f --show "$loop_dev"); do
+ losetup -d "$top_dev"
+ done
+}
+
+# Switch backing file of loop_dev continuously
+run_switcher() {
+ loop_dev="$1"
+
+ i=1
+ while src/loop_change_fd "$loop_dev" "$TMPDIR/file$i"; do
+ i=$(((i+1)%2))
+ done
+}
+
+test() {
+ echo "Running ${TEST_NAME}"
+
+ timeout=${TIMEOUT:-30}
+
+ truncate -s 1M "$TMPDIR/file0"
+ truncate -s 1M "$TMPDIR/file1"
+
+ if ! loop_dev="$(losetup -r -f --show "$TMPDIR/file0")"; then
+ return 1
+ fi
+
+ run_switcher "$loop_dev" &
+ switch_pid=$!
+ run_setter "$loop_dev" &
+ set_pid=$!
+
+ sleep $timeout
+
+ # Discard KILLED messages from bash...
+ {
+ kill -9 $switch_pid
+ kill -9 $set_pid
+ wait
+ sleep 1
+ } 2>/dev/null
+
+ # Clean up devices
+ top_dev=$(losetup -j "$loop_dev" | sed -e 's/\([^:]*\): .*/\1/')
+ if [[ -n "$top_dev" ]]; then
+ losetup -d "$top_dev"
+ fi
+ losetup -d "$loop_dev"
+
+ echo "Test complete"
+}
diff --git a/tests/loop/007.out b/tests/loop/007.out
new file mode 100644
index 000000000000..32752934d48a
--- /dev/null
+++ b/tests/loop/007.out
@@ -0,0 +1,2 @@
+Running loop/007
+Test complete
--
2.16.4
