lib/test_sysctl: support testing of sysctl. boot parameter

Testing is done by a new parameter debug.test_sysctl.boot_int which
defaults to 0 and it's expected that the tester passes a boot parameter
that sets it to 1.  The test checks if it's set to 1.

To distinguish true failure from parameter not being set, the test
checks /proc/cmdline for the expected parameter, and whether test_sysctl
is built-in and not a module.

[vbabka@suse.cz: skip the new test if boot_int sysctl is not present]
Link: http://lkml.kernel.org/r/305af605-1e60-cf84-fada-6ce1ca37c102@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Guilherme G . Piccoli" <gpiccoli@canonical.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200427180433.7029-6-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index 566dad3..84eaae2 100644 (file)
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -44,6 +44,8 @@ struct test_sysctl_data {
        int int_0002;
        int int_0003[4];
 
+       int boot_int;
+
        unsigned int uint_0001;
 
        char string_0001[65];
@@ -61,6 +63,8 @@ static struct test_sysctl_data test_data = {
        .int_0003[2] = 2,
        .int_0003[3] = 3,
 
+       .boot_int = 0,
+
        .uint_0001 = 314,
 
        .string_0001 = "(none)",
@@ -92,6 +96,15 @@ static struct ctl_table test_table[] = {
                .proc_handler   = proc_dointvec,
        },
        {
+               .procname       = "boot_int",
+               .data           = &test_data.boot_int,
+               .maxlen         = sizeof(test_data.boot_int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_ONE,
+       },
+       {
                .procname       = "uint_0001",
                .data           = &test_data.uint_0001,
                .maxlen         = sizeof(unsigned int),

diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
index a426295..0aa8a86 100755 (executable)
--- a/tools/testing/selftests/sysctl/sysctl.sh
+++ b/tools/testing/selftests/sysctl/sysctl.sh
@@ -39,6 +39,7 @@ ALL_TESTS="$ALL_TESTS 0003:1:1:int_0002"
 ALL_TESTS="$ALL_TESTS 0004:1:1:uint_0001"
 ALL_TESTS="$ALL_TESTS 0005:3:1:int_0003"
 ALL_TESTS="$ALL_TESTS 0006:50:1:bitmap_0001"
+ALL_TESTS="$ALL_TESTS 0007:1:1:boot_int"
 
 test_modprobe()
 {
@@ -752,6 +753,46 @@ sysctl_test_0006()
        run_bitmaptest
 }
 
+sysctl_test_0007()
+{
+       TARGET="${SYSCTL}/boot_int"
+       if [ ! -f $TARGET ]; then
+               echo "Skipping test for $TARGET as it is not present ..."
+               return $ksft_skip
+       fi
+
+       if [ -d $DIR ]; then
+               echo "Boot param test only possible sysctl_test is built-in, not module:"
+               cat $TEST_DIR/config >&2
+               return $ksft_skip
+       fi
+
+       echo -n "Testing if $TARGET is set to 1 ..."
+       ORIG=$(cat "${TARGET}")
+
+       if [ x$ORIG = "x1" ]; then
+               echo "ok"
+               return 0
+       fi
+       echo "FAIL"
+       echo "Checking if /proc/cmdline contains setting of the expected parameter ..."
+       if [ ! -f /proc/cmdline ]; then
+               echo "/proc/cmdline does not exist, test inconclusive"
+               return 0
+       fi
+
+       FOUND=$(grep -c "sysctl[./]debug[./]test_sysctl[./]boot_int=1" /proc/cmdline)
+       if [ $FOUND = "1" ]; then
+               echo "Kernel param found but $TARGET is not 1, TEST FAILED"
+               rc=1
+               test_rc
+       fi
+
+       echo "Skipping test, expected kernel parameter missing."
+       echo "To perform this test, make sure kernel is booted with parameter: sysctl.debug.test_sysctl.boot_int=1"
+       return $ksft_skip
+}
+
 list_tests()
 {
        echo "Test ID list:"
@@ -766,6 +807,7 @@ list_tests()
        echo "0004 x $(get_test_count 0004) - tests proc_douintvec()"
        echo "0005 x $(get_test_count 0005) - tests proc_douintvec() array"
        echo "0006 x $(get_test_count 0006) - tests proc_do_large_bitmap()"
+       echo "0007 x $(get_test_count 0007) - tests setting sysctl from kernel boot param"
 }
 
 usage()