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    Subject[for-linus][PATCH 09/27] kprobes: Add assertions for required lock
    From: Masami Hiramatsu <mhiramat@kernel.org>

    Add assertions for required locks instead of comment it
    so that the lockdep can inspect locks automatically.

    Link: https://lkml.kernel.org/r/163163039572.489837.18011973177537476885.stgit@devnote2

    Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
    Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
    ---
    kernel/kprobes.c | 19 ++++++++++++-------
    1 file changed, 12 insertions(+), 7 deletions(-)

    diff --git a/kernel/kprobes.c b/kernel/kprobes.c
    index ad39eeaa4371..ec3d97fd8c6b 100644
    --- a/kernel/kprobes.c
    +++ b/kernel/kprobes.c
    @@ -959,11 +959,13 @@ int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
    }
    #endif /* CONFIG_SYSCTL */

    -/* Put a breakpoint for a probe. Must be called with 'text_mutex' locked. */
    +/* Put a breakpoint for a probe. */
    static void __arm_kprobe(struct kprobe *p)
    {
    struct kprobe *_p;

    + lockdep_assert_held(&text_mutex);
    +
    /* Find the overlapping optimized kprobes. */
    _p = get_optimized_kprobe((unsigned long)p->addr);
    if (unlikely(_p))
    @@ -974,11 +976,13 @@ static void __arm_kprobe(struct kprobe *p)
    optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
    }

    -/* Remove the breakpoint of a probe. Must be called with 'text_mutex' locked. */
    +/* Remove the breakpoint of a probe. */
    static void __disarm_kprobe(struct kprobe *p, bool reopt)
    {
    struct kprobe *_p;

    + lockdep_assert_held(&text_mutex);
    +
    /* Try to unoptimize */
    unoptimize_kprobe(p, kprobes_all_disarmed);

    @@ -1047,12 +1051,13 @@ static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
    static int kprobe_ipmodify_enabled;
    static int kprobe_ftrace_enabled;

    -/* Caller must lock 'kprobe_mutex' */
    static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
    int *cnt)
    {
    int ret = 0;

    + lockdep_assert_held(&kprobe_mutex);
    +
    ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
    if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret))
    return ret;
    @@ -1084,12 +1089,13 @@ static int arm_kprobe_ftrace(struct kprobe *p)
    ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
    }

    -/* Caller must lock 'kprobe_mutex'. */
    static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
    int *cnt)
    {
    int ret = 0;

    + lockdep_assert_held(&kprobe_mutex);
    +
    if (*cnt == 1) {
    ret = unregister_ftrace_function(ops);
    if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret))
    @@ -1133,7 +1139,6 @@ static int prepare_kprobe(struct kprobe *p)
    return arch_prepare_kprobe(p);
    }

    -/* Arm a kprobe with 'text_mutex'. */
    static int arm_kprobe(struct kprobe *kp)
    {
    if (unlikely(kprobe_ftrace(kp)))
    @@ -1148,7 +1153,6 @@ static int arm_kprobe(struct kprobe *kp)
    return 0;
    }

    -/* Disarm a kprobe with 'text_mutex'. */
    static int disarm_kprobe(struct kprobe *kp, bool reopt)
    {
    if (unlikely(kprobe_ftrace(kp)))
    @@ -1691,12 +1695,13 @@ static int aggr_kprobe_disabled(struct kprobe *ap)
    return 1;
    }

    -/* Disable one kprobe: Make sure called under 'kprobe_mutex' is locked. */
    static struct kprobe *__disable_kprobe(struct kprobe *p)
    {
    struct kprobe *orig_p;
    int ret;

    + lockdep_assert_held(&kprobe_mutex);
    +
    /* Get an original kprobe for return */
    orig_p = __get_valid_kprobe(p);
    if (unlikely(orig_p == NULL))
    --
    2.32.0
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