Merge tag 'livepatching-for-6.11' of git://git.kernel.org/pub/scm/lin…

…ux/kernel/git/livepatching/livepatching

Pull livepatching update from Petr Mladek:

 - show patch->replace flag in sysfs

 - add or improve few selftests

* tag 'livepatching-for-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  livepatch: Replace snprintf() with sysfs_emit()
  selftests/livepatch: Add selftests for "replace" sysfs attribute
  livepatch: Add "replace" sysfs attribute
  selftests: livepatch: Test atomic replace against multiple modules
  selftests/livepatch: define max test-syscall processes

Documentation/ABI/testing/sysfs-kernel-livepatch

@@ -47,6 +47,14 @@ Description:
 		disabled when the feature is used. See
 		Documentation/livepatch/livepatch.rst for more information.
 
+What:		/sys/kernel/livepatch/<patch>/replace
+Date:		Jun 2024
+KernelVersion:	6.11.0
+Contact:	[email protected]
+Description:
+		An attribute which indicates whether the patch supports
+		atomic-replace.
+
 What:		/sys/kernel/livepatch/<patch>/<object>
 Date:		Nov 2014
 KernelVersion:	3.19.0

kernel/livepatch/core.c

@@ -346,6 +346,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
  * /sys/kernel/livepatch/<patch>/enabled
  * /sys/kernel/livepatch/<patch>/transition
  * /sys/kernel/livepatch/<patch>/force
+ * /sys/kernel/livepatch/<patch>/replace
  * /sys/kernel/livepatch/<patch>/<object>
  * /sys/kernel/livepatch/<patch>/<object>/patched
  * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
@@ -401,7 +402,7 @@ static ssize_t enabled_show(struct kobject *kobj,
 	struct klp_patch *patch;
 
 	patch = container_of(kobj, struct klp_patch, kobj);
-	return snprintf(buf, PAGE_SIZE-1, "%d\n", patch->enabled);
+	return sysfs_emit(buf, "%d\n", patch->enabled);
 }
 
 static ssize_t transition_show(struct kobject *kobj,
@@ -410,8 +411,7 @@ static ssize_t transition_show(struct kobject *kobj,
 	struct klp_patch *patch;
 
 	patch = container_of(kobj, struct klp_patch, kobj);
-	return snprintf(buf, PAGE_SIZE-1, "%d\n",
-			patch == klp_transition_patch);
+	return sysfs_emit(buf, "%d\n", patch == klp_transition_patch);
 }
 
 static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
@@ -443,13 +443,24 @@ static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
 	return count;
 }
 
+static ssize_t replace_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buf)
+{
+	struct klp_patch *patch;
+
+	patch = container_of(kobj, struct klp_patch, kobj);
+	return sysfs_emit(buf, "%d\n", patch->replace);
+}
+
 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 attribute *klp_patch_attrs[] = {
 	&enabled_kobj_attr.attr,
 	&transition_kobj_attr.attr,
 	&force_kobj_attr.attr,
+	&replace_kobj_attr.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(klp_patch);

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

@@ -4,7 +4,9 @@
 
 . $(dirname $0)/functions.sh
 
-MOD_LIVEPATCH=test_klp_livepatch
+MOD_LIVEPATCH1=test_klp_livepatch
+MOD_LIVEPATCH2=test_klp_syscall
+MOD_LIVEPATCH3=test_klp_callbacks_demo
 MOD_REPLACE=test_klp_atomic_replace
 
 setup_config
@@ -16,33 +18,33 @@ setup_config
 
 start_test "basic function patching"
 
-load_lp $MOD_LIVEPATCH
+load_lp $MOD_LIVEPATCH1
 
-if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then
+if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH1: this has been live patched" ]] ; then
 	echo -e "FAIL\n\n"
 	die "livepatch kselftest(s) failed"
 fi
 
-disable_lp $MOD_LIVEPATCH
-unload_lp $MOD_LIVEPATCH
+disable_lp $MOD_LIVEPATCH1
+unload_lp $MOD_LIVEPATCH1
 
-if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH1: this has been live patched" ]] ; then
 	echo -e "FAIL\n\n"
 	die "livepatch kselftest(s) failed"
 fi
 
-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
-% 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 $MOD_LIVEPATCH"
+check_result "% insmod test_modules/$MOD_LIVEPATCH1.ko
+livepatch: enabling patch '$MOD_LIVEPATCH1'
+livepatch: '$MOD_LIVEPATCH1': initializing patching transition
+livepatch: '$MOD_LIVEPATCH1': starting patching transition
+livepatch: '$MOD_LIVEPATCH1': completing patching transition
+livepatch: '$MOD_LIVEPATCH1': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH1/enabled
+livepatch: '$MOD_LIVEPATCH1': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH1': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH1': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH1': unpatching complete
+% rmmod $MOD_LIVEPATCH1"
 
 
 # - load a livepatch that modifies the output from /proc/cmdline and
@@ -53,7 +55,7 @@ livepatch: '$MOD_LIVEPATCH': unpatching complete
 
 start_test "multiple livepatches"
 
-load_lp $MOD_LIVEPATCH
+load_lp $MOD_LIVEPATCH1
 
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
@@ -69,62 +71,84 @@ unload_lp $MOD_REPLACE
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
 
-disable_lp $MOD_LIVEPATCH
-unload_lp $MOD_LIVEPATCH
+disable_lp $MOD_LIVEPATCH1
+unload_lp $MOD_LIVEPATCH1
 
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
 
-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
-$MOD_LIVEPATCH: this has been live patched
+check_result "% insmod test_modules/$MOD_LIVEPATCH1.ko
+livepatch: enabling patch '$MOD_LIVEPATCH1'
+livepatch: '$MOD_LIVEPATCH1': initializing patching transition
+livepatch: '$MOD_LIVEPATCH1': starting patching transition
+livepatch: '$MOD_LIVEPATCH1': completing patching transition
+livepatch: '$MOD_LIVEPATCH1': patching complete
+$MOD_LIVEPATCH1: this has been live patched
 % insmod test_modules/$MOD_REPLACE.ko replace=0
 livepatch: enabling patch '$MOD_REPLACE'
 livepatch: '$MOD_REPLACE': initializing patching transition
 livepatch: '$MOD_REPLACE': starting patching transition
 livepatch: '$MOD_REPLACE': completing patching transition
 livepatch: '$MOD_REPLACE': patching complete
-$MOD_LIVEPATCH: this has been live patched
+$MOD_LIVEPATCH1: this has been live patched
 $MOD_REPLACE: this has been live patched
 % echo 0 > /sys/kernel/livepatch/$MOD_REPLACE/enabled
 livepatch: '$MOD_REPLACE': initializing unpatching transition
 livepatch: '$MOD_REPLACE': starting unpatching transition
 livepatch: '$MOD_REPLACE': completing unpatching transition
 livepatch: '$MOD_REPLACE': unpatching complete
 % rmmod $MOD_REPLACE
-$MOD_LIVEPATCH: this has been live patched
-% 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 $MOD_LIVEPATCH"
+$MOD_LIVEPATCH1: this has been live patched
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH1/enabled
+livepatch: '$MOD_LIVEPATCH1': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH1': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH1': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH1': unpatching complete
+% rmmod $MOD_LIVEPATCH1"
 
 
 # - load a livepatch that modifies the output from /proc/cmdline and
 #   verify correct behavior
-# - load an atomic replace livepatch and verify that only the second is active
-# - remove the first livepatch and verify that the atomic replace livepatch
-#   is still active
+# - load two additional livepatches and check the number of livepatch modules
+#   applied
+# - load an atomic replace livepatch and check that the other three modules were
+#   disabled
+# - remove all livepatches besides the atomic replace one and verify that the
+#   atomic replace livepatch is still active
 # - remove the atomic replace livepatch and verify that none are active
 
 start_test "atomic replace livepatch"
 
-load_lp $MOD_LIVEPATCH
+load_lp $MOD_LIVEPATCH1
 
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
 
+for mod in $MOD_LIVEPATCH2 $MOD_LIVEPATCH3; do
+	load_lp "$mod"
+done
+
+mods=(/sys/kernel/livepatch/*)
+nmods=${#mods[@]}
+if [ "$nmods" -ne 3 ]; then
+	die "Expecting three modules listed, found $nmods"
+fi
+
 load_lp $MOD_REPLACE replace=1
 
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
 
-unload_lp $MOD_LIVEPATCH
+mods=(/sys/kernel/livepatch/*)
+nmods=${#mods[@]}
+if [ "$nmods" -ne 1 ]; then
+	die "Expecting only one moduled listed, found $nmods"
+fi
+
+# These modules were disabled by the atomic replace
+for mod in $MOD_LIVEPATCH3 $MOD_LIVEPATCH2 $MOD_LIVEPATCH1; do
+	unload_lp "$mod"
+done
 
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
@@ -135,21 +159,37 @@ unload_lp $MOD_REPLACE
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
 
-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
-$MOD_LIVEPATCH: this has been live patched
+check_result "% insmod test_modules/$MOD_LIVEPATCH1.ko
+livepatch: enabling patch '$MOD_LIVEPATCH1'
+livepatch: '$MOD_LIVEPATCH1': initializing patching transition
+livepatch: '$MOD_LIVEPATCH1': starting patching transition
+livepatch: '$MOD_LIVEPATCH1': completing patching transition
+livepatch: '$MOD_LIVEPATCH1': patching complete
+$MOD_LIVEPATCH1: this has been live patched
+% insmod test_modules/$MOD_LIVEPATCH2.ko
+livepatch: enabling patch '$MOD_LIVEPATCH2'
+livepatch: '$MOD_LIVEPATCH2': initializing patching transition
+livepatch: '$MOD_LIVEPATCH2': starting patching transition
+livepatch: '$MOD_LIVEPATCH2': completing patching transition
+livepatch: '$MOD_LIVEPATCH2': patching complete
+% insmod test_modules/$MOD_LIVEPATCH3.ko
+livepatch: enabling patch '$MOD_LIVEPATCH3'
+livepatch: '$MOD_LIVEPATCH3': initializing patching transition
+$MOD_LIVEPATCH3: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH3': starting patching transition
+livepatch: '$MOD_LIVEPATCH3': completing patching transition
+$MOD_LIVEPATCH3: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH3': patching complete
 % insmod test_modules/$MOD_REPLACE.ko replace=1
 livepatch: enabling patch '$MOD_REPLACE'
 livepatch: '$MOD_REPLACE': initializing patching transition
 livepatch: '$MOD_REPLACE': starting patching transition
 livepatch: '$MOD_REPLACE': completing patching transition
 livepatch: '$MOD_REPLACE': patching complete
 $MOD_REPLACE: this has been live patched
-% rmmod $MOD_LIVEPATCH
+% rmmod $MOD_LIVEPATCH3
+% rmmod $MOD_LIVEPATCH2
+% rmmod $MOD_LIVEPATCH1
 $MOD_REPLACE: this has been live patched
 % echo 0 > /sys/kernel/livepatch/$MOD_REPLACE/enabled
 livepatch: '$MOD_REPLACE': initializing unpatching transition

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

@@ -15,7 +15,10 @@ setup_config
 
 start_test "patch getpid syscall while being heavily hammered"
 
-for i in $(seq 1 $(getconf _NPROCESSORS_ONLN)); do
+NPROC=$(getconf _NPROCESSORS_ONLN)
+MAXPROC=128
+
+for i in $(seq 1 $(($NPROC < $MAXPROC ? $NPROC : $MAXPROC))); do
 	./test_klp-call_getpid &
 	pids[$i]="$!"
 done

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

@@ -18,6 +18,7 @@ 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 "$MOD_LIVEPATCH" "replace" "-r--r--r--"
 check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
 check_sysfs_value  "$MOD_LIVEPATCH" "transition" "0"
 check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
@@ -83,4 +84,51 @@ test_klp_callbacks_demo: post_unpatch_callback: vmlinux
 livepatch: 'test_klp_callbacks_demo': unpatching complete
 % rmmod test_klp_callbacks_demo"
 
+start_test "sysfs test replace enabled"
+
+MOD_LIVEPATCH=test_klp_atomic_replace
+load_lp $MOD_LIVEPATCH replace=1
+
+check_sysfs_rights "$MOD_LIVEPATCH" "replace" "-r--r--r--"
+check_sysfs_value  "$MOD_LIVEPATCH" "replace" "1"
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% insmod test_modules/$MOD_LIVEPATCH.ko replace=1
+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 replace disabled"
+
+load_lp $MOD_LIVEPATCH replace=0
+
+check_sysfs_rights "$MOD_LIVEPATCH" "replace" "-r--r--r--"
+check_sysfs_value  "$MOD_LIVEPATCH" "replace" "0"
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% insmod test_modules/$MOD_LIVEPATCH.ko replace=0
+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"
+
 exit 0