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authorLinus Torvalds <torvalds@linux-foundation.org>2022-10-10 11:36:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-10-10 11:36:19 -0700
commit4de65c5830233e7a4adf2e679510089ec4e210c7 (patch)
tree1b43fc3da753b18242bbad08c68ef65fa0a1a2a9
parentb520410654103086ccc0d339c0ff645d4c4dd697 (diff)
parent59b2a38c6afdc9341ac4fcff455bfdf77113ed37 (diff)
Merge tag 'livepatching-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
Pull livepatching updates from Petr Mladek: - Fix race between fork and livepatch transition revert - Add sysfs entry that shows "patched" state for each object (module) that can be livepatched by the given livepatch - Some clean up * tag 'livepatching-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching: selftests/livepatch: add sysfs test livepatch: add sysfs entry "patched" for each klp_object selftests/livepatch: normalize sysctl error message livepatch: Add a missing newline character in klp_module_coming() livepatch: fix race between fork and KLP transition
-rw-r--r--Documentation/ABI/testing/sysfs-kernel-livepatch8
-rw-r--r--kernel/livepatch/core.c20
-rw-r--r--kernel/livepatch/transition.c18
-rw-r--r--tools/testing/selftests/livepatch/Makefile3
-rw-r--r--tools/testing/selftests/livepatch/functions.sh36
-rwxr-xr-xtools/testing/selftests/livepatch/test-sysfs.sh86
6 files changed, 166 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch
index bea7bd5a1d5f..a5df9b4910dc 100644
--- a/Documentation/ABI/testing/sysfs-kernel-livepatch
+++ b/Documentation/ABI/testing/sysfs-kernel-livepatch
@@ -55,6 +55,14 @@ Description:
The object directory contains subdirectories for each function
that is patched within the object.
+What: /sys/kernel/livepatch/<patch>/<object>/patched
+Date: August 2022
+KernelVersion: 6.1.0
+Contact: live-patching@vger.kernel.org
+Description:
+ An attribute which indicates whether the object is currently
+ patched.
+
What: /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
Date: Nov 2014
KernelVersion: 3.19.0
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index ec06ce59d728..9ada0bc5247b 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -325,6 +325,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
* /sys/kernel/livepatch/<patch>/transition
* /sys/kernel/livepatch/<patch>/force
* /sys/kernel/livepatch/<patch>/<object>
+ * /sys/kernel/livepatch/<patch>/<object>/patched
* /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
*/
static int __klp_disable_patch(struct klp_patch *patch);
@@ -431,6 +432,22 @@ static struct attribute *klp_patch_attrs[] = {
};
ATTRIBUTE_GROUPS(klp_patch);
+static ssize_t patched_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct klp_object *obj;
+
+ obj = container_of(kobj, struct klp_object, kobj);
+ return sysfs_emit(buf, "%d\n", obj->patched);
+}
+
+static struct kobj_attribute patched_kobj_attr = __ATTR_RO(patched);
+static struct attribute *klp_object_attrs[] = {
+ &patched_kobj_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(klp_object);
+
static void klp_free_object_dynamic(struct klp_object *obj)
{
kfree(obj->name);
@@ -576,6 +593,7 @@ static void klp_kobj_release_object(struct kobject *kobj)
static struct kobj_type klp_ktype_object = {
.release = klp_kobj_release_object,
.sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = klp_object_groups,
};
static void klp_kobj_release_func(struct kobject *kobj)
@@ -1171,7 +1189,7 @@ int klp_module_coming(struct module *mod)
return -EINVAL;
if (!strcmp(mod->name, "vmlinux")) {
- pr_err("vmlinux.ko: invalid module name");
+ pr_err("vmlinux.ko: invalid module name\n");
return -EINVAL;
}
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 5d03a2ad1066..30187b1d8275 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -610,9 +610,23 @@ void klp_reverse_transition(void)
/* Called from copy_process() during fork */
void klp_copy_process(struct task_struct *child)
{
- child->patch_state = current->patch_state;
- /* TIF_PATCH_PENDING gets copied in setup_thread_stack() */
+ /*
+ * The parent process may have gone through a KLP transition since
+ * the thread flag was copied in setup_thread_stack earlier. Bring
+ * the task flag up to date with the parent here.
+ *
+ * The operation is serialized against all klp_*_transition()
+ * operations by the tasklist_lock. The only exception is
+ * klp_update_patch_state(current), but we cannot race with
+ * that because we are current.
+ */
+ if (test_tsk_thread_flag(current, TIF_PATCH_PENDING))
+ set_tsk_thread_flag(child, TIF_PATCH_PENDING);
+ else
+ clear_tsk_thread_flag(child, TIF_PATCH_PENDING);
+
+ child->patch_state = current->patch_state;
}
/*
diff --git a/tools/testing/selftests/livepatch/Makefile b/tools/testing/selftests/livepatch/Makefile
index 1acc9e1fa3fb..02fadc9d55e0 100644
--- a/tools/testing/selftests/livepatch/Makefile
+++ b/tools/testing/selftests/livepatch/Makefile
@@ -6,7 +6,8 @@ TEST_PROGS := \
test-callbacks.sh \
test-shadow-vars.sh \
test-state.sh \
- test-ftrace.sh
+ test-ftrace.sh \
+ test-sysfs.sh
TEST_FILES := settings
diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh
index 9230b869371d..c8416c54b463 100644
--- a/tools/testing/selftests/livepatch/functions.sh
+++ b/tools/testing/selftests/livepatch/functions.sh
@@ -6,6 +6,7 @@
MAX_RETRIES=600
RETRY_INTERVAL=".1" # seconds
+KLP_SYSFS_DIR="/sys/kernel/livepatch"
# Kselftest framework requirement - SKIP code is 4
ksft_skip=4
@@ -86,7 +87,7 @@ function set_ftrace_enabled() {
if [[ "$result" != "$1" ]] ; then
if [[ $can_fail -eq 1 ]] ; then
- echo "livepatch: $err" > /dev/kmsg
+ echo "livepatch: $err" | sed 's#/proc/sys/kernel/#kernel.#' > /dev/kmsg
return
fi
@@ -308,3 +309,36 @@ function check_result {
cleanup_dmesg_file
}
+
+# check_sysfs_rights(modname, rel_path, expected_rights) - check sysfs
+# path permissions
+# modname - livepatch module creating the sysfs interface
+# rel_path - relative path of the sysfs interface
+# expected_rights - expected access rights
+function check_sysfs_rights() {
+ local mod="$1"; shift
+ local rel_path="$1"; shift
+ local expected_rights="$1"; shift
+
+ local path="$KLP_SYSFS_DIR/$mod/$rel_path"
+ local rights=$(/bin/stat --format '%A' "$path")
+ if test "$rights" != "$expected_rights" ; then
+ die "Unexpected access rights of $path: $expected_rights vs. $rights"
+ fi
+}
+
+# check_sysfs_value(modname, rel_path, expected_value) - check sysfs value
+# modname - livepatch module creating the sysfs interface
+# rel_path - relative path of the sysfs interface
+# expected_value - expected value read from the file
+function check_sysfs_value() {
+ local mod="$1"; shift
+ local rel_path="$1"; shift
+ local expected_value="$1"; shift
+
+ local path="$KLP_SYSFS_DIR/$mod/$rel_path"
+ local value=`cat $path`
+ if test "$value" != "$expected_value" ; then
+ die "Unexpected value in $path: $expected_value vs. $value"
+ fi
+}
diff --git a/tools/testing/selftests/livepatch/test-sysfs.sh b/tools/testing/selftests/livepatch/test-sysfs.sh
new file mode 100755
index 000000000000..7f76f280189a
--- /dev/null
+++ b/tools/testing/selftests/livepatch/test-sysfs.sh
@@ -0,0 +1,86 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2022 Song Liu <song@kernel.org>
+
+. $(dirname $0)/functions.sh
+
+MOD_LIVEPATCH=test_klp_livepatch
+
+setup_config
+
+# - load a livepatch and verifies the sysfs entries work as expected
+
+start_test "sysfs test"
+
+load_lp $MOD_LIVEPATCH
+
+check_sysfs_rights "$MOD_LIVEPATCH" "" "drwxr-xr-x"
+check_sysfs_rights "$MOD_LIVEPATCH" "enabled" "-rw-r--r--"
+check_sysfs_value "$MOD_LIVEPATCH" "enabled" "1"
+check_sysfs_rights "$MOD_LIVEPATCH" "force" "--w-------"
+check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
+check_sysfs_value "$MOD_LIVEPATCH" "transition" "0"
+check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
+check_sysfs_value "$MOD_LIVEPATCH" "vmlinux/patched" "1"
+
+disable_lp $MOD_LIVEPATCH
+
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+start_test "sysfs test object/patched"
+
+MOD_LIVEPATCH=test_klp_callbacks_demo
+MOD_TARGET=test_klp_callbacks_mod
+load_lp $MOD_LIVEPATCH
+
+# check the "patch" file changes as target module loads/unloads
+check_sysfs_value "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
+load_mod $MOD_TARGET
+check_sysfs_value "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "1"
+unload_mod $MOD_TARGET
+check_sysfs_value "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe test_klp_callbacks_demo
+livepatch: enabling patch 'test_klp_callbacks_demo'
+livepatch: 'test_klp_callbacks_demo': initializing patching transition
+test_klp_callbacks_demo: pre_patch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': starting patching transition
+livepatch: 'test_klp_callbacks_demo': completing patching transition
+test_klp_callbacks_demo: post_patch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': patching complete
+% modprobe test_klp_callbacks_mod
+livepatch: applying patch 'test_klp_callbacks_demo' to loading module 'test_klp_callbacks_mod'
+test_klp_callbacks_demo: pre_patch_callback: test_klp_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
+test_klp_callbacks_demo: post_patch_callback: test_klp_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
+test_klp_callbacks_mod: test_klp_callbacks_mod_init
+% rmmod test_klp_callbacks_mod
+test_klp_callbacks_mod: test_klp_callbacks_mod_exit
+test_klp_callbacks_demo: pre_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away
+livepatch: reverting patch 'test_klp_callbacks_demo' on unloading module 'test_klp_callbacks_mod'
+test_klp_callbacks_demo: post_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away
+% echo 0 > /sys/kernel/livepatch/test_klp_callbacks_demo/enabled
+livepatch: 'test_klp_callbacks_demo': initializing unpatching transition
+test_klp_callbacks_demo: pre_unpatch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': starting unpatching transition
+livepatch: 'test_klp_callbacks_demo': completing unpatching transition
+test_klp_callbacks_demo: post_unpatch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': unpatching complete
+% rmmod test_klp_callbacks_demo"
+
+exit 0