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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
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‎Documentation/ABI/testing/sysfs-kernel-livepatch‎

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@@ -55,6 +55,15 @@ Description:
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An attribute which indicates whether the patch supports
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atomic-replace.
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What: /sys/kernel/livepatch/<patch>/stack_order
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Date: Jan 2025
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KernelVersion: 6.14.0
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Description:
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This attribute specifies the sequence in which live patch modules
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are applied to the system. If multiple live patches modify the same
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function, the implementation with the biggest 'stack_order' number
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is used, unless a transition is currently in progress.
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What: /sys/kernel/livepatch/<patch>/<object>
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Date: Nov 2014
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KernelVersion: 3.19.0

‎kernel/livepatch/core.c‎

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Original file line numberDiff line numberDiff line change
@@ -347,6 +347,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
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* /sys/kernel/livepatch/<patch>/transition
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* /sys/kernel/livepatch/<patch>/force
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* /sys/kernel/livepatch/<patch>/replace
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* /sys/kernel/livepatch/<patch>/stack_order
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* /sys/kernel/livepatch/<patch>/<object>
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* /sys/kernel/livepatch/<patch>/<object>/patched
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* /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
@@ -452,15 +453,38 @@ static ssize_t replace_show(struct kobject *kobj,
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return sysfs_emit(buf, "%d\n", patch->replace);
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}
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static ssize_t stack_order_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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struct klp_patch *patch, *this_patch;
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int stack_order = 0;
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this_patch = container_of(kobj, struct klp_patch, kobj);
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mutex_lock(&klp_mutex);
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klp_for_each_patch(patch) {
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stack_order++;
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if (patch == this_patch)
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break;
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}
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mutex_unlock(&klp_mutex);
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return sysfs_emit(buf, "%d\n", stack_order);
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}
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static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);
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static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);
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static struct kobj_attribute force_kobj_attr = __ATTR_WO(force);
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static struct kobj_attribute replace_kobj_attr = __ATTR_RO(replace);
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static struct kobj_attribute stack_order_kobj_attr = __ATTR_RO(stack_order);
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static struct attribute *klp_patch_attrs[] = {
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&enabled_kobj_attr.attr,
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&transition_kobj_attr.attr,
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&force_kobj_attr.attr,
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&replace_kobj_attr.attr,
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&stack_order_kobj_attr.attr,
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NULL
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};
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ATTRIBUTE_GROUPS(klp_patch);

‎tools/testing/selftests/livepatch/test-callbacks.sh‎

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Original file line numberDiff line numberDiff line change
@@ -259,7 +259,7 @@ $MOD_TARGET: ${MOD_TARGET}_init
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% insmod test_modules/$MOD_LIVEPATCH.ko pre_patch_ret=-19
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livepatch: enabling patch '$MOD_LIVEPATCH'
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livepatch: '$MOD_LIVEPATCH': initializing patching transition
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test_klp_callbacks_demo: pre_patch_callback: vmlinux
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$MOD_LIVEPATCH: pre_patch_callback: vmlinux
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livepatch: pre-patch callback failed for object 'vmlinux'
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livepatch: failed to enable patch '$MOD_LIVEPATCH'
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livepatch: '$MOD_LIVEPATCH': canceling patching transition, going to unpatch

‎tools/testing/selftests/livepatch/test-sysfs.sh‎

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@@ -5,6 +5,8 @@
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. $(dirname $0)/functions.sh
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MOD_LIVEPATCH=test_klp_livepatch
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MOD_LIVEPATCH2=test_klp_callbacks_demo
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MOD_LIVEPATCH3=test_klp_syscall
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setup_config
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@@ -19,6 +21,8 @@ check_sysfs_rights "$MOD_LIVEPATCH" "enabled" "-rw-r--r--"
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check_sysfs_value "$MOD_LIVEPATCH" "enabled" "1"
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check_sysfs_rights "$MOD_LIVEPATCH" "force" "--w-------"
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check_sysfs_rights "$MOD_LIVEPATCH" "replace" "-r--r--r--"
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check_sysfs_rights "$MOD_LIVEPATCH" "stack_order" "-r--r--r--"
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check_sysfs_value "$MOD_LIVEPATCH" "stack_order" "1"
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check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
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check_sysfs_value "$MOD_LIVEPATCH" "transition" "0"
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check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
@@ -131,4 +135,71 @@ livepatch: '$MOD_LIVEPATCH': completing unpatching transition
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livepatch: '$MOD_LIVEPATCH': unpatching complete
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% rmmod $MOD_LIVEPATCH"
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start_test "sysfs test stack_order value"
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load_lp $MOD_LIVEPATCH
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check_sysfs_value "$MOD_LIVEPATCH" "stack_order" "1"
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load_lp $MOD_LIVEPATCH2
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check_sysfs_value "$MOD_LIVEPATCH2" "stack_order" "2"
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load_lp $MOD_LIVEPATCH3
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check_sysfs_value "$MOD_LIVEPATCH3" "stack_order" "3"
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disable_lp $MOD_LIVEPATCH2
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unload_lp $MOD_LIVEPATCH2
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check_sysfs_value "$MOD_LIVEPATCH" "stack_order" "1"
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check_sysfs_value "$MOD_LIVEPATCH3" "stack_order" "2"
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disable_lp $MOD_LIVEPATCH3
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unload_lp $MOD_LIVEPATCH3
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disable_lp $MOD_LIVEPATCH
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unload_lp $MOD_LIVEPATCH
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check_result "% insmod test_modules/$MOD_LIVEPATCH.ko
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livepatch: enabling patch '$MOD_LIVEPATCH'
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livepatch: '$MOD_LIVEPATCH': initializing patching transition
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livepatch: '$MOD_LIVEPATCH': starting patching transition
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livepatch: '$MOD_LIVEPATCH': completing patching transition
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livepatch: '$MOD_LIVEPATCH': patching complete
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% insmod test_modules/$MOD_LIVEPATCH2.ko
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livepatch: enabling patch '$MOD_LIVEPATCH2'
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livepatch: '$MOD_LIVEPATCH2': initializing patching transition
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$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
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livepatch: '$MOD_LIVEPATCH2': starting patching transition
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livepatch: '$MOD_LIVEPATCH2': completing patching transition
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$MOD_LIVEPATCH2: post_patch_callback: vmlinux
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livepatch: '$MOD_LIVEPATCH2': patching complete
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% insmod test_modules/$MOD_LIVEPATCH3.ko
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livepatch: enabling patch '$MOD_LIVEPATCH3'
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livepatch: '$MOD_LIVEPATCH3': initializing patching transition
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livepatch: '$MOD_LIVEPATCH3': starting patching transition
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livepatch: '$MOD_LIVEPATCH3': completing patching transition
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livepatch: '$MOD_LIVEPATCH3': patching complete
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% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
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livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
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$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
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livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
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livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
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$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
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livepatch: '$MOD_LIVEPATCH2': unpatching complete
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% rmmod $MOD_LIVEPATCH2
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% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH3/enabled
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livepatch: '$MOD_LIVEPATCH3': initializing unpatching transition
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livepatch: '$MOD_LIVEPATCH3': starting unpatching transition
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livepatch: '$MOD_LIVEPATCH3': completing unpatching transition
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livepatch: '$MOD_LIVEPATCH3': unpatching complete
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% rmmod $MOD_LIVEPATCH3
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% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
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livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
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livepatch: '$MOD_LIVEPATCH': starting unpatching transition
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livepatch: '$MOD_LIVEPATCH': completing unpatching transition
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livepatch: '$MOD_LIVEPATCH': unpatching complete
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% rmmod $MOD_LIVEPATCH"
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exit 0

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