Merge tag 'livepatching-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
Pull livepatching updates from Petr Mladek:
- Add a sysfs attribute showing the livepatch ordering
- Some code clean up
* tag 'livepatching-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
selftests: livepatch: add test cases of stack_order sysfs interface
livepatch: Add stack_order sysfs attribute
selftests/livepatch: Replace hardcoded module name with variable in test-callbacks.sh
diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch
index 3735d86..3c3f36b 100644
--- a/Documentation/ABI/testing/sysfs-kernel-livepatch
+++ b/Documentation/ABI/testing/sysfs-kernel-livepatch
@@ -55,6 +55,15 @@
An attribute which indicates whether the patch supports
atomic-replace.
+What: /sys/kernel/livepatch/<patch>/stack_order
+Date: Jan 2025
+KernelVersion: 6.14.0
+Description:
+ This attribute specifies the sequence in which live patch modules
+ are applied to the system. If multiple live patches modify the same
+ function, the implementation with the biggest 'stack_order' number
+ is used, unless a transition is currently in progress.
+
What: /sys/kernel/livepatch/<patch>/<object>
Date: Nov 2014
KernelVersion: 3.19.0
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 3c21c317..0cd3995 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -347,6 +347,7 @@ 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>/replace
+ * /sys/kernel/livepatch/<patch>/stack_order
* /sys/kernel/livepatch/<patch>/<object>
* /sys/kernel/livepatch/<patch>/<object>/patched
* /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
@@ -452,15 +453,38 @@ static ssize_t replace_show(struct kobject *kobj,
return sysfs_emit(buf, "%d\n", patch->replace);
}
+static ssize_t stack_order_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct klp_patch *patch, *this_patch;
+ int stack_order = 0;
+
+ this_patch = container_of(kobj, struct klp_patch, kobj);
+
+ mutex_lock(&klp_mutex);
+
+ klp_for_each_patch(patch) {
+ stack_order++;
+ if (patch == this_patch)
+ break;
+ }
+
+ mutex_unlock(&klp_mutex);
+
+ return sysfs_emit(buf, "%d\n", stack_order);
+}
+
static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);
static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);
static struct kobj_attribute force_kobj_attr = __ATTR_WO(force);
static struct kobj_attribute replace_kobj_attr = __ATTR_RO(replace);
+static struct kobj_attribute stack_order_kobj_attr = __ATTR_RO(stack_order);
static struct attribute *klp_patch_attrs[] = {
&enabled_kobj_attr.attr,
&transition_kobj_attr.attr,
&force_kobj_attr.attr,
&replace_kobj_attr.attr,
+ &stack_order_kobj_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(klp_patch);
diff --git a/tools/testing/selftests/livepatch/test-callbacks.sh b/tools/testing/selftests/livepatch/test-callbacks.sh
index 37bbc3f..2a03deb 100755
--- a/tools/testing/selftests/livepatch/test-callbacks.sh
+++ b/tools/testing/selftests/livepatch/test-callbacks.sh
@@ -259,7 +259,7 @@
% insmod test_modules/$MOD_LIVEPATCH.ko pre_patch_ret=-19
livepatch: enabling patch '$MOD_LIVEPATCH'
livepatch: '$MOD_LIVEPATCH': initializing patching transition
-test_klp_callbacks_demo: pre_patch_callback: vmlinux
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
livepatch: pre-patch callback failed for object 'vmlinux'
livepatch: failed to enable patch '$MOD_LIVEPATCH'
livepatch: '$MOD_LIVEPATCH': canceling patching transition, going to unpatch
diff --git a/tools/testing/selftests/livepatch/test-sysfs.sh b/tools/testing/selftests/livepatch/test-sysfs.sh
index 2c91428..58fe1d9 100755
--- a/tools/testing/selftests/livepatch/test-sysfs.sh
+++ b/tools/testing/selftests/livepatch/test-sysfs.sh
@@ -5,6 +5,8 @@
. $(dirname $0)/functions.sh
MOD_LIVEPATCH=test_klp_livepatch
+MOD_LIVEPATCH2=test_klp_callbacks_demo
+MOD_LIVEPATCH3=test_klp_syscall
setup_config
@@ -19,6 +21,8 @@
check_sysfs_value "$MOD_LIVEPATCH" "enabled" "1"
check_sysfs_rights "$MOD_LIVEPATCH" "force" "--w-------"
check_sysfs_rights "$MOD_LIVEPATCH" "replace" "-r--r--r--"
+check_sysfs_rights "$MOD_LIVEPATCH" "stack_order" "-r--r--r--"
+check_sysfs_value "$MOD_LIVEPATCH" "stack_order" "1"
check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
check_sysfs_value "$MOD_LIVEPATCH" "transition" "0"
check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
@@ -131,4 +135,71 @@
livepatch: '$MOD_LIVEPATCH': unpatching complete
% rmmod $MOD_LIVEPATCH"
+start_test "sysfs test stack_order value"
+
+load_lp $MOD_LIVEPATCH
+
+check_sysfs_value "$MOD_LIVEPATCH" "stack_order" "1"
+
+load_lp $MOD_LIVEPATCH2
+
+check_sysfs_value "$MOD_LIVEPATCH2" "stack_order" "2"
+
+load_lp $MOD_LIVEPATCH3
+
+check_sysfs_value "$MOD_LIVEPATCH3" "stack_order" "3"
+
+disable_lp $MOD_LIVEPATCH2
+unload_lp $MOD_LIVEPATCH2
+
+check_sysfs_value "$MOD_LIVEPATCH" "stack_order" "1"
+check_sysfs_value "$MOD_LIVEPATCH3" "stack_order" "2"
+
+disable_lp $MOD_LIVEPATCH3
+unload_lp $MOD_LIVEPATCH3
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% insmod test_modules/$MOD_LIVEPATCH.ko
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+% insmod test_modules/$MOD_LIVEPATCH2.ko
+livepatch: enabling patch '$MOD_LIVEPATCH2'
+livepatch: '$MOD_LIVEPATCH2': initializing patching transition
+$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': starting patching transition
+livepatch: '$MOD_LIVEPATCH2': completing patching transition
+$MOD_LIVEPATCH2: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': patching complete
+% insmod test_modules/$MOD_LIVEPATCH3.ko
+livepatch: enabling patch '$MOD_LIVEPATCH3'
+livepatch: '$MOD_LIVEPATCH3': initializing patching transition
+livepatch: '$MOD_LIVEPATCH3': starting patching transition
+livepatch: '$MOD_LIVEPATCH3': completing patching transition
+livepatch: '$MOD_LIVEPATCH3': patching complete
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
+livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
+$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
+$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': unpatching complete
+% rmmod $MOD_LIVEPATCH2
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH3/enabled
+livepatch: '$MOD_LIVEPATCH3': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH3': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH3': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH3': unpatching complete
+% rmmod $MOD_LIVEPATCH3
+% echo 0 > $SYSFS_KLP_DIR/$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"
+
exit 0
