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    Subject[RFC PATCH -tip v4 4/9] kprobes: Introduce kprobes jump optimization
    Date
    Introduce kprobes jump optimization arch-independent parts.
    Kprobes uses breakpoint instruction for interrupting execution flow, on
    some architectures, it can be replaced by a jump instruction and
    interruption emulation code. This gains kprobs' performance drastically.

    To enable this feature, set CONFIG_OPTPROBES=y (default y if the arch
    supports OPTPROBE).

    Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
    Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Jim Keniston <jkenisto@us.ibm.com>
    Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
    Cc: Christoph Hellwig <hch@infradead.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Anders Kaseorg <andersk@ksplice.com>
    Cc: Tim Abbott <tabbott@ksplice.com>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: Jason Baron <jbaron@redhat.com>
    ---

    arch/Kconfig | 13 ++
    include/linux/kprobes.h | 36 ++++
    kernel/kprobes.c | 390 +++++++++++++++++++++++++++++++++++++++++------
    3 files changed, 393 insertions(+), 46 deletions(-)

    diff --git a/arch/Kconfig b/arch/Kconfig
    index 99193b1..dbab672 100644
    --- a/arch/Kconfig
    +++ b/arch/Kconfig
    @@ -44,6 +44,17 @@ config KPROBES
    for kernel debugging, non-intrusive instrumentation and testing.
    If in doubt, say "N".

    +config OPTPROBES
    + bool "Kprobes jump optimization support (EXPERIMENTAL)"
    + default y
    + depends on KPROBES
    + depends on !PREEMPT
    + depends on HAVE_OPTPROBES
    + select KALLSYMS_ALL
    + help
    + This option will allow kprobes to optimize breakpoint to
    + a jump for reducing its overhead.
    +
    config HAVE_EFFICIENT_UNALIGNED_ACCESS
    bool
    help
    @@ -79,6 +90,8 @@ config HAVE_KPROBES
    config HAVE_KRETPROBES
    bool

    +config HAVE_OPTPROBES
    + bool
    #
    # An arch should select this if it provides all these things:
    #
    diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
    index 87eb79c..dd05756 100644
    --- a/include/linux/kprobes.h
    +++ b/include/linux/kprobes.h
    @@ -122,6 +122,11 @@ struct kprobe {
    /* Kprobe status flags */
    #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
    #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
    +#define KPROBE_FLAG_OPTIMIZED 4 /*
    + * probe is really optimized.
    + * NOTE:
    + * this flag is only for optimized_kprobe.
    + */

    /* Has this kprobe gone ? */
    static inline int kprobe_gone(struct kprobe *p)
    @@ -134,6 +139,12 @@ static inline int kprobe_disabled(struct kprobe *p)
    {
    return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
    }
    +
    +/* Is this kprobe really running optimized path ? */
    +static inline int kprobe_optimized(struct kprobe *p)
    +{
    + return p->flags & KPROBE_FLAG_OPTIMIZED;
    +}
    /*
    * Special probe type that uses setjmp-longjmp type tricks to resume
    * execution at a specified entry with a matching prototype corresponding
    @@ -249,6 +260,31 @@ extern kprobe_opcode_t *get_insn_slot(void);
    extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
    extern void kprobes_inc_nmissed_count(struct kprobe *p);

    +#ifdef CONFIG_OPTPROBES
    +/*
    + * Internal structure for direct jump optimized probe
    + */
    +struct optimized_kprobe {
    + struct kprobe kp;
    + struct list_head list; /* list for optimizing queue */
    + struct arch_optimized_insn optinsn;
    +};
    +
    +/* Architecture dependent functions for direct jump optimization */
    +extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
    +extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
    +extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
    +extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
    +extern int arch_optimize_kprobe(struct optimized_kprobe *op);
    +extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
    +extern kprobe_opcode_t *get_optinsn_slot(void);
    +extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
    +extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
    + unsigned long addr);
    +
    +extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
    +#endif /* CONFIG_OPTPROBES */
    +
    /* Get the kprobe at this addr (if any) - called with preemption disabled */
    struct kprobe *get_kprobe(void *addr);
    void kretprobe_hash_lock(struct task_struct *tsk,
    diff --git a/kernel/kprobes.c b/kernel/kprobes.c
    index a74f0e0..9053aea 100644
    --- a/kernel/kprobes.c
    +++ b/kernel/kprobes.c
    @@ -301,6 +301,31 @@ void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
    __free_insn_slot(&kprobe_insn_slots, slot, dirty);
    mutex_unlock(&kprobe_insn_mutex);
    }
    +#ifdef CONFIG_OPTPROBES
    +/* For optimized_kprobe buffer */
    +static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
    +static struct kprobe_insn_cache kprobe_optinsn_slots = {
    + .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
    + /* .insn_size is initialized later */
    + .nr_garbage = 0,
    +};
    +/* Get a slot for optimized_kprobe buffer */
    +kprobe_opcode_t __kprobes *get_optinsn_slot(void)
    +{
    + kprobe_opcode_t *ret = NULL;
    + mutex_lock(&kprobe_optinsn_mutex);
    + ret = __get_insn_slot(&kprobe_optinsn_slots);
    + mutex_unlock(&kprobe_optinsn_mutex);
    + return ret;
    +}
    +
    +void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
    +{
    + mutex_lock(&kprobe_optinsn_mutex);
    + __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
    + mutex_unlock(&kprobe_optinsn_mutex);
    +}
    +#endif
    #endif

    /* We have preemption disabled.. so it is safe to use __ versions */
    @@ -334,11 +359,256 @@ struct kprobe __kprobes *get_kprobe(void *addr)
    return NULL;
    }

    +static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
    +
    +/* Return true if the kprobe is an aggregator */
    +static inline int kprobe_aggrprobe(struct kprobe *p)
    +{
    + return p->pre_handler == aggr_pre_handler;
    +}
    +
    +/*
    + * Keep all fields in the kprobe consistent
    + */
    +static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
    +{
    + memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
    + memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
    +}
    +
    +#ifdef CONFIG_OPTPROBES
    +/*
    + * Call all pre_handler on the list, but ignores its return value.
    + * This must be called from arch-dep optimized caller.
    + */
    +void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
    +{
    + struct kprobe *kp;
    +
    + list_for_each_entry_rcu(kp, &p->list, list) {
    + if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
    + set_kprobe_instance(kp);
    + kp->pre_handler(kp, regs);
    + }
    + reset_kprobe_instance();
    + }
    +}
    +
    +/* Return true(!0) if the kprobe is ready for optimization. */
    +static inline int kprobe_optready(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    + if (kprobe_aggrprobe(p)) {
    + op = container_of(p, struct optimized_kprobe, kp);
    + return arch_prepared_optinsn(&op->optinsn);
    + }
    + return 0;
    +}
    +
    +/* Return an optimized kprobe which replaces instructions including addr. */
    +struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
    +{
    + int i;
    + struct kprobe *p = NULL;
    + struct optimized_kprobe *op;
    + for (i = 0; !p && i < MAX_OPTIMIZED_LENGTH; i++)
    + p = get_kprobe((void *)(addr - i));
    +
    + if (p && kprobe_optready(p)) {
    + op = container_of(p, struct optimized_kprobe, kp);
    + if (arch_within_optimized_kprobe(op, addr))
    + return p;
    + }
    + return NULL;
    +}
    +
    +/* Optimization staging list, protected by kprobe_mutex */
    +static LIST_HEAD(optimizing_list);
    +
    +static void kprobe_optimizer(struct work_struct *work);
    +static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
    +#define OPTIMIZE_DELAY 5
    +
    +/* Kprobe jump optimizer */
    +static __kprobes void kprobe_optimizer(struct work_struct *work)
    +{
    + struct optimized_kprobe *op, *tmp;
    +
    + /* Lock modules while optimizing kprobes */
    + mutex_lock(&module_mutex);
    + mutex_lock(&kprobe_mutex);
    + if (kprobes_all_disarmed)
    + goto end;
    +
    + /* Wait quiesence period for ensuring all interrupts are done */
    + synchronize_sched();
    +
    + mutex_lock(&text_mutex);
    + list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
    + WARN_ON(kprobe_disabled(&op->kp));
    + if (arch_optimize_kprobe(op) < 0)
    + op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
    + list_del_init(&op->list);
    + }
    + mutex_unlock(&text_mutex);
    +end:
    + mutex_unlock(&kprobe_mutex);
    + mutex_unlock(&module_mutex);
    +}
    +
    +/* Optimize kprobe if p is ready to be optimized */
    +static __kprobes void optimize_kprobe(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    + /* Check if the kprobe is disabled or not ready for optimization. */
    + if (!kprobe_optready(p) ||
    + (kprobe_disabled(p) || kprobes_all_disarmed))
    + return;
    +
    + /* Both of break_handler and post_handler are not supported. */
    + if (p->break_handler || p->post_handler)
    + return;
    +
    + op = container_of(p, struct optimized_kprobe, kp);
    +
    + /* Check there is no other kprobes at the optimized instructions */
    + if (arch_check_optimized_kprobe(op) < 0)
    + return;
    +
    + /* Check if it is already optimized. */
    + if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
    + return;
    +
    + op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
    + list_add(&op->list, &optimizing_list);
    + if (!delayed_work_pending(&optimizing_work))
    + schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
    +}
    +
    +/* Unoptimize a kprobe if p is optimized */
    +static __kprobes void unoptimize_kprobe(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    + if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
    + op = container_of(p, struct optimized_kprobe, kp);
    + if (!list_empty(&op->list))
    + /* Dequeue from the optimization queue */
    + list_del_init(&op->list);
    + else
    + /* Replace jump with break */
    + arch_unoptimize_kprobe(op);
    + op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
    + }
    +}
    +
    +/* Remove optimized instructions */
    +static void __kprobes kill_optimized_kprobe(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    + op = container_of(p, struct optimized_kprobe, kp);
    + if (!list_empty(&op->list)) {
    + /* Dequeue from the optimization queue */
    + list_del_init(&op->list);
    + op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
    + }
    + /* Don't unoptimize, because the target code will be freed. */
    + arch_remove_optimized_kprobe(op);
    +}
    +
    +/* Try to prepare optimized instructions */
    +static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    + op = container_of(p, struct optimized_kprobe, kp);
    + arch_prepare_optimized_kprobe(op);
    +}
    +
    +/* Free optimized instructions and optimized_kprobe */
    +static __kprobes void free_aggr_kprobe(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    + op = container_of(p, struct optimized_kprobe, kp);
    + arch_remove_optimized_kprobe(op);
    + kfree(op);
    +}
    +
    +/* Allocate new optimized_kprobe and try to prepare optimized instructions */
    +static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
    +{
    + struct optimized_kprobe *op;
    +
    + op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
    + if (!op)
    + return NULL;
    +
    + INIT_LIST_HEAD(&op->list);
    + op->kp.addr = p->addr;
    + arch_prepare_optimized_kprobe(op);
    + return &op->kp;
    +}
    +
    +static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
    +
    +/*
    + * Prepare an optimized_kprobe and optimize it
    + * NOTE: p must be a normal registered kprobe
    + */
    +static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
    +{
    + struct kprobe *ap;
    + struct optimized_kprobe *op;
    +
    + ap = alloc_aggr_kprobe(p);
    + if (!ap)
    + return;
    +
    + op = container_of(ap, struct optimized_kprobe, kp);
    + if (!arch_prepared_optinsn(&op->optinsn)) {
    + /* If failed to setup optimizing, fallback to kprobe */
    + free_aggr_kprobe(ap);
    + return;
    + }
    +
    + init_aggr_kprobe(ap, p);
    + optimize_kprobe(ap);
    + return;
    +}
    +#else /* !CONFIG_OPTPROBES */
    +#define get_optimized_kprobe(addr) (NULL)
    +#define optimize_kprobe(p) do {} while (0)
    +#define unoptimize_kprobe(p) do {} while (0)
    +#define kill_optimized_kprobe(p) do {} while (0)
    +#define prepare_optimized_kprobe(p) do {} while (0)
    +#define try_to_optimize_kprobe(p) do {} while (0)
    +
    +static __kprobes void free_aggr_kprobe(struct kprobe *p)
    +{
    + kfree(p);
    +}
    +
    +static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
    +{
    + return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
    +}
    +#endif /* CONFIG_OPTPROBES */
    +
    +static void __kprobes __arm_kprobe(struct kprobe *kp)
    +{
    + arch_arm_kprobe(kp);
    + optimize_kprobe(kp); /* Try to re-optimize */
    +}
    +
    +static void __kprobes __disarm_kprobe(struct kprobe *kp)
    +{
    + unoptimize_kprobe(kp); /* Try to unoptimize */
    + arch_disarm_kprobe(kp);
    +}
    +
    /* Arm a kprobe with text_mutex */
    static void __kprobes arm_kprobe(struct kprobe *kp)
    {
    mutex_lock(&text_mutex);
    - arch_arm_kprobe(kp);
    + __arm_kprobe(kp);
    mutex_unlock(&text_mutex);
    }

    @@ -346,7 +616,7 @@ static void __kprobes arm_kprobe(struct kprobe *kp)
    static void __kprobes disarm_kprobe(struct kprobe *kp)
    {
    mutex_lock(&text_mutex);
    - arch_disarm_kprobe(kp);
    + __disarm_kprobe(kp);
    mutex_unlock(&text_mutex);
    }

    @@ -416,7 +686,7 @@ static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
    void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
    {
    struct kprobe *kp;
    - if (p->pre_handler != aggr_pre_handler) {
    + if (!kprobe_aggrprobe(p)) {
    p->nmissed++;
    } else {
    list_for_each_entry_rcu(kp, &p->list, list)
    @@ -540,21 +810,16 @@ static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
    }

    /*
    - * Keep all fields in the kprobe consistent
    - */
    -static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
    -{
    - memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
    - memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
    -}
    -
    -/*
    * Add the new probe to ap->list. Fail if this is the
    * second jprobe at the address - two jprobes can't coexist
    */
    static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
    {
    BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
    +
    + if (p->break_handler || p->post_handler)
    + unoptimize_kprobe(ap); /* Fall back to normal kprobe */
    +
    if (p->break_handler) {
    if (ap->break_handler)
    return -EEXIST;
    @@ -569,7 +834,7 @@ static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
    ap->flags &= ~KPROBE_FLAG_DISABLED;
    if (!kprobes_all_disarmed)
    /* Arm the breakpoint again. */
    - arm_kprobe(ap);
    + __arm_kprobe(ap);
    }
    return 0;
    }
    @@ -578,12 +843,13 @@ static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
    * Fill in the required fields of the "manager kprobe". Replace the
    * earlier kprobe in the hlist with the manager kprobe
    */
    -static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
    +static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
    {
    + /* Copy p's insn slot to ap */
    copy_kprobe(p, ap);
    flush_insn_slot(ap);
    ap->addr = p->addr;
    - ap->flags = p->flags;
    + ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
    ap->pre_handler = aggr_pre_handler;
    ap->fault_handler = aggr_fault_handler;
    /* We don't care the kprobe which has gone. */
    @@ -593,8 +859,9 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
    ap->break_handler = aggr_break_handler;

    INIT_LIST_HEAD(&ap->list);
    - list_add_rcu(&p->list, &ap->list);
    + INIT_HLIST_NODE(&ap->hlist);

    + list_add_rcu(&p->list, &ap->list);
    hlist_replace_rcu(&p->hlist, &ap->hlist);
    }

    @@ -608,12 +875,12 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
    int ret = 0;
    struct kprobe *ap = old_p;

    - if (old_p->pre_handler != aggr_pre_handler) {
    - /* If old_p is not an aggr_probe, create new aggr_kprobe. */
    - ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
    + if (!kprobe_aggrprobe(old_p)) {
    + /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */
    + ap = alloc_aggr_kprobe(old_p);
    if (!ap)
    return -ENOMEM;
    - add_aggr_kprobe(ap, old_p);
    + init_aggr_kprobe(ap, old_p);
    }

    if (kprobe_gone(ap)) {
    @@ -632,6 +899,9 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
    */
    return ret;

    + /* Prepare optimized instructions if possible. */
    + prepare_optimized_kprobe(ap);
    +
    /*
    * Clear gone flag to prevent allocating new slot again, and
    * set disabled flag because it is not armed yet.
    @@ -640,6 +910,7 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
    | KPROBE_FLAG_DISABLED;
    }

    + /* Copy ap's insn slot to p */
    copy_kprobe(ap, p);
    return add_new_kprobe(ap, p);
    }
    @@ -751,16 +1022,23 @@ int __kprobes register_kprobe(struct kprobe *p)
    p->nmissed = 0;
    INIT_LIST_HEAD(&p->list);
    mutex_lock(&kprobe_mutex);
    + mutex_lock(&text_mutex);
    +
    old_p = get_kprobe(p->addr);
    if (old_p) {
    + /* Since this may unoptimize old_p, locking text_mutex. */
    ret = register_aggr_kprobe(old_p, p);
    goto out;
    }

    - mutex_lock(&text_mutex);
    + /* Check collision with other optimized kprobes */
    + old_p = get_optimized_kprobe((unsigned long)p->addr);
    + if (unlikely(old_p))
    + unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */
    +
    ret = arch_prepare_kprobe(p);
    if (ret)
    - goto out_unlock_text;
    + goto out;

    INIT_HLIST_NODE(&p->hlist);
    hlist_add_head_rcu(&p->hlist,
    @@ -769,9 +1047,11 @@ int __kprobes register_kprobe(struct kprobe *p)
    if (!kprobes_all_disarmed && !kprobe_disabled(p))
    arch_arm_kprobe(p);

    -out_unlock_text:
    - mutex_unlock(&text_mutex);
    + /* Try to optimize kprobe */
    + try_to_optimize_kprobe(p);
    +
    out:
    + mutex_unlock(&text_mutex);
    mutex_unlock(&kprobe_mutex);

    if (probed_mod)
    @@ -813,7 +1093,7 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
    return -EINVAL;

    if (old_p == p ||
    - (old_p->pre_handler == aggr_pre_handler &&
    + (kprobe_aggrprobe(old_p) &&
    list_is_singular(&old_p->list))) {
    /*
    * Only probe on the hash list. Disarm only if kprobes are
    @@ -821,8 +1101,13 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
    * already have been removed. We save on flushing icache.
    */
    if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
    - disarm_kprobe(p);
    + disarm_kprobe(old_p);
    hlist_del_rcu(&old_p->hlist);
    +
    + /* If another kprobe was blocked, optimize it. */
    + old_p = get_optimized_kprobe((unsigned long)p->addr);
    + if (unlikely(old_p))
    + optimize_kprobe(old_p);
    } else {
    if (p->break_handler && !kprobe_gone(p))
    old_p->break_handler = NULL;
    @@ -837,8 +1122,13 @@ noclean:
    list_del_rcu(&p->list);
    if (!kprobe_disabled(old_p)) {
    try_to_disable_aggr_kprobe(old_p);
    - if (!kprobes_all_disarmed && kprobe_disabled(old_p))
    - disarm_kprobe(old_p);
    + if (!kprobes_all_disarmed) {
    + if (kprobe_disabled(old_p))
    + disarm_kprobe(old_p);
    + else
    + /* Try to optimize this probe again */
    + optimize_kprobe(old_p);
    + }
    }
    }
    return 0;
    @@ -855,7 +1145,7 @@ static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
    old_p = list_entry(p->list.next, struct kprobe, list);
    list_del(&p->list);
    arch_remove_kprobe(old_p);
    - kfree(old_p);
    + free_aggr_kprobe(old_p);
    }
    }

    @@ -1151,7 +1441,7 @@ static void __kprobes kill_kprobe(struct kprobe *p)
    struct kprobe *kp;

    p->flags |= KPROBE_FLAG_GONE;
    - if (p->pre_handler == aggr_pre_handler) {
    + if (kprobe_aggrprobe(p)) {
    /*
    * If this is an aggr_kprobe, we have to list all the
    * chained probes and mark them GONE.
    @@ -1160,6 +1450,7 @@ static void __kprobes kill_kprobe(struct kprobe *p)
    kp->flags |= KPROBE_FLAG_GONE;
    p->post_handler = NULL;
    p->break_handler = NULL;
    + kill_optimized_kprobe(p);
    }
    /*
    * Here, we can remove insn_slot safely, because no thread calls
    @@ -1269,6 +1560,11 @@ static int __init init_kprobes(void)
    }
    }

    +#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
    + /* Init kprobe_optinsn_slots */
    + kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
    +#endif
    +
    /* By default, kprobes are armed */
    kprobes_all_disarmed = false;

    @@ -1287,7 +1583,7 @@ static int __init init_kprobes(void)

    #ifdef CONFIG_DEBUG_FS
    static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
    - const char *sym, int offset,char *modname)
    + const char *sym, int offset, char *modname, struct kprobe *pp)
    {
    char *kprobe_type;

    @@ -1297,19 +1593,21 @@ static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
    kprobe_type = "j";
    else
    kprobe_type = "k";
    +
    if (sym)
    - seq_printf(pi, "%p %s %s+0x%x %s %s%s\n",
    + seq_printf(pi, "%p %s %s+0x%x %s ",
    p->addr, kprobe_type, sym, offset,
    - (modname ? modname : " "),
    - (kprobe_gone(p) ? "[GONE]" : ""),
    - ((kprobe_disabled(p) && !kprobe_gone(p)) ?
    - "[DISABLED]" : ""));
    + (modname ? modname : " "));
    else
    - seq_printf(pi, "%p %s %p %s%s\n",
    - p->addr, kprobe_type, p->addr,
    - (kprobe_gone(p) ? "[GONE]" : ""),
    - ((kprobe_disabled(p) && !kprobe_gone(p)) ?
    - "[DISABLED]" : ""));
    + seq_printf(pi, "%p %s %p ",
    + p->addr, kprobe_type, p->addr);
    +
    + if (!pp)
    + pp = p;
    + seq_printf(pi, "%s%s%s\n",
    + (kprobe_gone(p) ? "[GONE]" : ""),
    + ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
    + (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
    }

    static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
    @@ -1345,11 +1643,11 @@ static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
    hlist_for_each_entry_rcu(p, node, head, hlist) {
    sym = kallsyms_lookup((unsigned long)p->addr, NULL,
    &offset, &modname, namebuf);
    - if (p->pre_handler == aggr_pre_handler) {
    + if (kprobe_aggrprobe(p)) {
    list_for_each_entry_rcu(kp, &p->list, list)
    - report_probe(pi, kp, sym, offset, modname);
    + report_probe(pi, kp, sym, offset, modname, p);
    } else
    - report_probe(pi, p, sym, offset, modname);
    + report_probe(pi, p, sym, offset, modname, NULL);
    }
    preempt_enable();
    return 0;
    @@ -1457,7 +1755,7 @@ static void __kprobes arm_all_kprobes(void)
    head = &kprobe_table[i];
    hlist_for_each_entry_rcu(p, node, head, hlist)
    if (!kprobe_disabled(p))
    - arch_arm_kprobe(p);
    + __arm_kprobe(p);
    }
    mutex_unlock(&text_mutex);

    @@ -1489,7 +1787,7 @@ static void __kprobes disarm_all_kprobes(void)
    head = &kprobe_table[i];
    hlist_for_each_entry_rcu(p, node, head, hlist) {
    if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
    - arch_disarm_kprobe(p);
    + __disarm_kprobe(p);
    }
    }


    --
    Masami Hiramatsu

    Software Engineer
    Hitachi Computer Products (America), Inc.
    Software Solutions Division

    e-mail: mhiramat@redhat.com


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