diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-livepatch | 12 | ||||
| -rw-r--r-- | Documentation/livepatch/livepatch.txt | 15 | ||||
| -rw-r--r-- | MAINTAINERS | 6 | ||||
| -rw-r--r-- | kernel/livepatch/core.c | 32 | ||||
| -rw-r--r-- | kernel/livepatch/transition.c | 92 | ||||
| -rw-r--r-- | kernel/livepatch/transition.h | 1 | ||||
| -rw-r--r-- | samples/livepatch/livepatch-shadow-fix1.c | 4 | ||||
| -rw-r--r-- | samples/livepatch/livepatch-shadow-fix2.c | 4 | ||||
| -rw-r--r-- | samples/livepatch/livepatch-shadow-mod.c | 11 |
9 files changed, 71 insertions, 106 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch index dac7e1e62a8b..85db352f68f9 100644 --- a/Documentation/ABI/testing/sysfs-kernel-livepatch +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -33,18 +33,6 @@ Description: An attribute which indicates whether the patch is currently in transition. -What: /sys/kernel/livepatch/<patch>/signal -Date: Nov 2017 -KernelVersion: 4.15.0 -Contact: live-patching@vger.kernel.org -Description: - A writable attribute that allows administrator to affect the - course of an existing transition. Writing 1 sends a fake - signal to all remaining blocking tasks. The fake signal - means that no proper signal is delivered (there is no data in - signal pending structures). Tasks are interrupted or woken up, - and forced to change their patched state. - What: /sys/kernel/livepatch/<patch>/force Date: Nov 2017 KernelVersion: 4.15.0 diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt index 71d7f286ec4d..4627b41ff02e 100644 --- a/Documentation/livepatch/livepatch.txt +++ b/Documentation/livepatch/livepatch.txt @@ -158,12 +158,11 @@ If a patch is in transition, this file shows 0 to indicate the task is unpatched and 1 to indicate it's patched. Otherwise, if no patch is in transition, it shows -1. Any tasks which are blocking the transition can be signaled with SIGSTOP and SIGCONT to force them to change their -patched state. This may be harmful to the system though. -/sys/kernel/livepatch/<patch>/signal attribute provides a better alternative. -Writing 1 to the attribute sends a fake signal to all remaining blocking -tasks. No proper signal is actually delivered (there is no data in signal -pending structures). Tasks are interrupted or woken up, and forced to change -their patched state. +patched state. This may be harmful to the system though. Sending a fake signal +to all remaining blocking tasks is a better alternative. No proper signal is +actually delivered (there is no data in signal pending structures). Tasks are +interrupted or woken up, and forced to change their patched state. The fake +signal is automatically sent every 15 seconds. Administrator can also affect a transition through /sys/kernel/livepatch/<patch>/force attribute. Writing 1 there clears @@ -411,8 +410,8 @@ Information about the registered patches can be found under /sys/kernel/livepatch. The patches could be enabled and disabled by writing there. -/sys/kernel/livepatch/<patch>/signal and /sys/kernel/livepatch/<patch>/force -attributes allow administrator to affect a patching operation. +/sys/kernel/livepatch/<patch>/force attributes allow administrator to affect a +patching operation. See Documentation/ABI/testing/sysfs-kernel-livepatch for more details. diff --git a/MAINTAINERS b/MAINTAINERS index b1c5cf166703..7bd760639b78 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8820,10 +8820,10 @@ F: drivers/platform/x86/hp_accel.c LIVE PATCHING M: Josh Poimboeuf <jpoimboe@redhat.com> -M: Jessica Yu <jeyu@kernel.org> M: Jiri Kosina <jikos@kernel.org> M: Miroslav Benes <mbenes@suse.cz> -R: Petr Mladek <pmladek@suse.com> +M: Petr Mladek <pmladek@suse.com> +R: Joe Lawrence <joe.lawrence@redhat.com> S: Maintained F: kernel/livepatch/ F: include/linux/livepatch.h @@ -8834,7 +8834,7 @@ F: Documentation/ABI/testing/sysfs-kernel-livepatch F: samples/livepatch/ F: tools/testing/selftests/livepatch/ L: live-patching@vger.kernel.org -T: git git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching.git +T: git git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.git LLC (802.2) L: netdev@vger.kernel.org diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index d1af69e9f0e3..eb0ee10a1981 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -313,7 +313,6 @@ static int klp_write_object_relocations(struct module *pmod, * /sys/kernel/livepatch/<patch> * /sys/kernel/livepatch/<patch>/enabled * /sys/kernel/livepatch/<patch>/transition - * /sys/kernel/livepatch/<patch>/signal * /sys/kernel/livepatch/<patch>/force * /sys/kernel/livepatch/<patch>/<object> * /sys/kernel/livepatch/<patch>/<object>/<function,sympos> @@ -382,35 +381,6 @@ static ssize_t transition_show(struct kobject *kobj, patch == klp_transition_patch); } -static ssize_t signal_store(struct kobject *kobj, struct kobj_attribute *attr, - const char *buf, size_t count) -{ - struct klp_patch *patch; - int ret; - bool val; - - ret = kstrtobool(buf, &val); - if (ret) - return ret; - - if (!val) - return count; - - mutex_lock(&klp_mutex); - - patch = container_of(kobj, struct klp_patch, kobj); - if (patch != klp_transition_patch) { - mutex_unlock(&klp_mutex); - return -EINVAL; - } - - klp_send_signals(); - - mutex_unlock(&klp_mutex); - - return count; -} - static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { @@ -442,12 +412,10 @@ static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr, static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled); static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition); -static struct kobj_attribute signal_kobj_attr = __ATTR_WO(signal); static struct kobj_attribute force_kobj_attr = __ATTR_WO(force); static struct attribute *klp_patch_attrs[] = { &enabled_kobj_attr.attr, &transition_kobj_attr.attr, - &signal_kobj_attr.attr, &force_kobj_attr.attr, NULL }; diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index a3a6f32c6fd0..9c89ae8b337a 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -29,10 +29,14 @@ #define MAX_STACK_ENTRIES 100 #define STACK_ERR_BUF_SIZE 128 +#define SIGNALS_TIMEOUT 15 + struct klp_patch *klp_transition_patch; static int klp_target_state = KLP_UNDEFINED; +static unsigned int klp_signals_cnt; + /* * This work can be performed periodically to finish patching or unpatching any * "straggler" tasks which failed to transition in the first attempt. @@ -344,6 +348,47 @@ done: } /* + * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set. + * Kthreads with TIF_PATCH_PENDING set are woken up. + */ +static void klp_send_signals(void) +{ + struct task_struct *g, *task; + + if (klp_signals_cnt == SIGNALS_TIMEOUT) + pr_notice("signaling remaining tasks\n"); + + read_lock(&tasklist_lock); + for_each_process_thread(g, task) { + if (!klp_patch_pending(task)) + continue; + + /* + * There is a small race here. We could see TIF_PATCH_PENDING + * set and decide to wake up a kthread or send a fake signal. + * Meanwhile the task could migrate itself and the action + * would be meaningless. It is not serious though. + */ + if (task->flags & PF_KTHREAD) { + /* + * Wake up a kthread which sleeps interruptedly and + * still has not been migrated. + */ + wake_up_state(task, TASK_INTERRUPTIBLE); + } else { + /* + * Send fake signal to all non-kthread tasks which are + * still not migrated. + */ + spin_lock_irq(&task->sighand->siglock); + signal_wake_up(task, 0); + spin_unlock_irq(&task->sighand->siglock); + } + } + read_unlock(&tasklist_lock); +} + +/* * Try to switch all remaining tasks to the target patch state by walking the * stacks of sleeping tasks and looking for any to-be-patched or * to-be-unpatched functions. If such functions are found, the task can't be @@ -393,6 +438,10 @@ void klp_try_complete_transition(void) put_online_cpus(); if (!complete) { + if (klp_signals_cnt && !(klp_signals_cnt % SIGNALS_TIMEOUT)) + klp_send_signals(); + klp_signals_cnt++; + /* * Some tasks weren't able to be switched over. Try again * later and/or wait for other methods like kernel exit @@ -454,6 +503,8 @@ void klp_start_transition(void) if (task->patch_state != klp_target_state) set_tsk_thread_flag(task, TIF_PATCH_PENDING); } + + klp_signals_cnt = 0; } /* @@ -577,47 +628,6 @@ void klp_copy_process(struct task_struct *child) } /* - * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set. - * Kthreads with TIF_PATCH_PENDING set are woken up. Only admin can request this - * action currently. - */ -void klp_send_signals(void) -{ - struct task_struct *g, *task; - - pr_notice("signaling remaining tasks\n"); - - read_lock(&tasklist_lock); - for_each_process_thread(g, task) { - if (!klp_patch_pending(task)) - continue; - - /* - * There is a small race here. We could see TIF_PATCH_PENDING - * set and decide to wake up a kthread or send a fake signal. - * Meanwhile the task could migrate itself and the action - * would be meaningless. It is not serious though. - */ - if (task->flags & PF_KTHREAD) { - /* - * Wake up a kthread which sleeps interruptedly and - * still has not been migrated. - */ - wake_up_state(task, TASK_INTERRUPTIBLE); - } else { - /* - * Send fake signal to all non-kthread tasks which are - * still not migrated. - */ - spin_lock_irq(&task->sighand->siglock); - signal_wake_up(task, 0); - spin_unlock_irq(&task->sighand->siglock); - } - } - read_unlock(&tasklist_lock); -} - -/* * Drop TIF_PATCH_PENDING of all tasks on admin's request. This forces an * existing transition to finish. * diff --git a/kernel/livepatch/transition.h b/kernel/livepatch/transition.h index f9d0bc016067..322db16233de 100644 --- a/kernel/livepatch/transition.h +++ b/kernel/livepatch/transition.h @@ -11,7 +11,6 @@ void klp_cancel_transition(void); void klp_start_transition(void); void klp_try_complete_transition(void); void klp_reverse_transition(void); -void klp_send_signals(void); void klp_force_transition(void); #endif /* _LIVEPATCH_TRANSITION_H */ diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c index a5a5cac21d4d..67a73e5e986e 100644 --- a/samples/livepatch/livepatch-shadow-fix1.c +++ b/samples/livepatch/livepatch-shadow-fix1.c @@ -71,7 +71,7 @@ static int shadow_leak_ctor(void *obj, void *shadow_data, void *ctor_data) return 0; } -struct dummy *livepatch_fix1_dummy_alloc(void) +static struct dummy *livepatch_fix1_dummy_alloc(void) { struct dummy *d; void *leak; @@ -113,7 +113,7 @@ static void livepatch_fix1_dummy_leak_dtor(void *obj, void *shadow_data) __func__, d, *shadow_leak); } -void livepatch_fix1_dummy_free(struct dummy *d) +static void livepatch_fix1_dummy_free(struct dummy *d) { void **shadow_leak; diff --git a/samples/livepatch/livepatch-shadow-fix2.c b/samples/livepatch/livepatch-shadow-fix2.c index 52de947b5526..91c21d52cfea 100644 --- a/samples/livepatch/livepatch-shadow-fix2.c +++ b/samples/livepatch/livepatch-shadow-fix2.c @@ -50,7 +50,7 @@ struct dummy { unsigned long jiffies_expire; }; -bool livepatch_fix2_dummy_check(struct dummy *d, unsigned long jiffies) +static bool livepatch_fix2_dummy_check(struct dummy *d, unsigned long jiffies) { int *shadow_count; @@ -78,7 +78,7 @@ static void livepatch_fix2_dummy_leak_dtor(void *obj, void *shadow_data) __func__, d, *shadow_leak); } -void livepatch_fix2_dummy_free(struct dummy *d) +static void livepatch_fix2_dummy_free(struct dummy *d) { void **shadow_leak; int *shadow_count; diff --git a/samples/livepatch/livepatch-shadow-mod.c b/samples/livepatch/livepatch-shadow-mod.c index 4aa8a88d3cd6..4d79c6dc055b 100644 --- a/samples/livepatch/livepatch-shadow-mod.c +++ b/samples/livepatch/livepatch-shadow-mod.c @@ -96,15 +96,15 @@ MODULE_DESCRIPTION("Buggy module for shadow variable demo"); * Keep a list of all the dummies so we can clean up any residual ones * on module exit */ -LIST_HEAD(dummy_list); -DEFINE_MUTEX(dummy_list_mutex); +static LIST_HEAD(dummy_list); +static DEFINE_MUTEX(dummy_list_mutex); struct dummy { struct list_head list; unsigned long jiffies_expire; }; -noinline struct dummy *dummy_alloc(void) +static __used noinline struct dummy *dummy_alloc(void) { struct dummy *d; void *leak; @@ -129,7 +129,7 @@ noinline struct dummy *dummy_alloc(void) return d; } -noinline void dummy_free(struct dummy *d) +static __used noinline void dummy_free(struct dummy *d) { pr_info("%s: dummy @ %p, expired = %lx\n", __func__, d, d->jiffies_expire); @@ -137,7 +137,8 @@ noinline void dummy_free(struct dummy *d) kfree(d); } -noinline bool dummy_check(struct dummy *d, unsigned long jiffies) +static __used noinline bool dummy_check(struct dummy *d, + unsigned long jiffies) { return time_after(jiffies, d->jiffies_expire); } |