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    Subject[PATCH v2 06/12] tracing/kprobe: Add per-probe delete from event
    Date
    Allow user to delete a probe from event. This is done by head
    match. For example, if we have 2 probes on an event

    $ cat kprobe_events
    p:kprobes/testprobe _do_fork r1=%ax r2=%dx
    p:kprobes/testprobe idle_fork r1=%ax r2=%cx

    Then you can remove one of them by passing the head of definition
    which identify the probe.

    $ echo "-:kprobes/testprobe idle_fork" >> kprobe_events

    Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
    ---
    kernel/trace/trace_kprobe.c | 25 ++++++++++++++++++++++++-
    kernel/trace/trace_probe.c | 18 ++++++++++++++++++
    kernel/trace/trace_probe.h | 2 ++
    3 files changed, 44 insertions(+), 1 deletion(-)

    diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
    index f43098bf62dd..18c4175b6585 100644
    --- a/kernel/trace/trace_kprobe.c
    +++ b/kernel/trace/trace_kprobe.c
    @@ -137,13 +137,36 @@ static bool trace_kprobe_is_busy(struct dyn_event *ev)
    return trace_probe_is_enabled(&tk->tp);
    }

    +static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
    + int argc, const char **argv)
    +{
    + char buf[MAX_ARGSTR_LEN + 1];
    +
    + if (!argc)
    + return true;
    +
    + if (!tk->symbol)
    + snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
    + else if (tk->rp.kp.offset)
    + snprintf(buf, sizeof(buf), "%s+%u",
    + trace_kprobe_symbol(tk), tk->rp.kp.offset);
    + else
    + snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
    + if (strcmp(buf, argv[0]))
    + return false;
    + argc--; argv++;
    +
    + return trace_probe_match_command_args(&tk->tp, argc, argv);
    +}
    +
    static bool trace_kprobe_match(const char *system, const char *event,
    int argc, const char **argv, struct dyn_event *ev)
    {
    struct trace_kprobe *tk = to_trace_kprobe(ev);

    return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
    - (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0);
    + (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
    + trace_kprobe_match_command_head(tk, argc, argv);
    }

    static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
    diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
    index 651a1449acde..f8c3c65c035d 100644
    --- a/kernel/trace/trace_probe.c
    +++ b/kernel/trace/trace_probe.c
    @@ -1047,3 +1047,21 @@ int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)

    return 0;
    }
    +
    +bool trace_probe_match_command_args(struct trace_probe *tp,
    + int argc, const char **argv)
    +{
    + char buf[MAX_ARGSTR_LEN + 1];
    + int i;
    +
    + if (tp->nr_args < argc)
    + return false;
    +
    + for (i = 0; i < argc; i++) {
    + snprintf(buf, sizeof(buf), "%s=%s",
    + tp->args[i].name, tp->args[i].comm);
    + if (strcmp(buf, argv[i]))
    + return false;
    + }
    + return true;
    +}
    diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
    index 39926e8a344b..2dcc4e317787 100644
    --- a/kernel/trace/trace_probe.h
    +++ b/kernel/trace/trace_probe.h
    @@ -332,6 +332,8 @@ int trace_probe_remove_file(struct trace_probe *tp,
    struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
    struct trace_event_file *file);
    int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b);
    +bool trace_probe_match_command_args(struct trace_probe *tp,
    + int argc, const char **argv);

    #define trace_probe_for_each_link(pos, tp) \
    list_for_each_entry(pos, &(tp)->event->files, list)
    \
     
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      Last update: 2019-06-19 17:08    [W:4.220 / U:0.012 seconds]
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