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Livepatching changes for 6.11

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Merge tag 'livepatching-for-6.11' of git://git.kernel.org/pub/scm/linux/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
This commit is contained in:
Linus Torvalds 2024-07-23 11:11:51 -07:00
commit d2d721e2eb
5 changed files with 163 additions and 53 deletions
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8
Documentation/ABI/testing/sysfs-kernel-livepatch
View File

@ -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: live-patching@vger.kernel.org
Description:
An attribute which indicates whether the patch supports
atomic-replace.
What: /sys/kernel/livepatch/<patch>/<object>
Date: Nov 2014
KernelVersion: 3.19.0

17
kernel/livepatch/core.c
View File

@ -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);

138
tools/testing/selftests/livepatch/test-livepatch.sh
View File

@ -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
@ -69,26 +71,26 @@ 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: '$MOD_REPLACE': initializing unpatching transition
@ -96,35 +98,57 @@ livepatch: '$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
@ -135,13 +159,27 @@ 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: '$MOD_REPLACE': initializing patching transition
@ -149,7 +187,9 @@ livepatch: '$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

5
tools/testing/selftests/livepatch/test-syscall.sh
View File

@ -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

48
tools/testing/selftests/livepatch/test-sysfs.sh
View File

@ -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