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    Subject[RFC PATCH v2 02/15] tracing: kprobes: Output kprobe event to printk buffer
    Date
    Since kprobe-events use event_trigger_unlock_commit_regs() directly,
    that events doesn't show up in printk buffer if "tp_printk" is set.

    Use trace_event_buffer_commit() in kprobe events so that it can
    invoke output_printk() as same as other trace events.

    Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
    ---
    include/linux/trace_events.h | 1 +
    kernel/trace/trace.c | 4 +--
    kernel/trace/trace_events.c | 1 +
    kernel/trace/trace_kprobe.c | 57 +++++++++++++++++++++---------------------
    4 files changed, 32 insertions(+), 31 deletions(-)

    diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
    index 5150436783e8..8912ccdb3d4b 100644
    --- a/include/linux/trace_events.h
    +++ b/include/linux/trace_events.h
    @@ -211,6 +211,7 @@ struct trace_event_buffer {
    void *entry;
    unsigned long flags;
    int pc;
    + struct pt_regs *regs;
    };

    void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
    diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
    index 047f37816bf1..30f09c058f79 100644
    --- a/kernel/trace/trace.c
    +++ b/kernel/trace/trace.c
    @@ -2572,9 +2572,9 @@ void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
    if (static_key_false(&tracepoint_printk_key.key))
    output_printk(fbuffer);

    - event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
    + event_trigger_unlock_commit_regs(fbuffer->trace_file, fbuffer->buffer,
    fbuffer->event, fbuffer->entry,
    - fbuffer->flags, fbuffer->pc);
    + fbuffer->flags, fbuffer->pc, fbuffer->regs);
    }
    EXPORT_SYMBOL_GPL(trace_event_buffer_commit);

    diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
    index c7506bc81b75..22cf08bd2317 100644
    --- a/kernel/trace/trace_events.c
    +++ b/kernel/trace/trace_events.c
    @@ -271,6 +271,7 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
    if (!fbuffer->event)
    return NULL;

    + fbuffer->regs = NULL;
    fbuffer->entry = ring_buffer_event_data(fbuffer->event);
    return fbuffer->entry;
    }
    diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
    index 9d483ad9bb6c..6c5145525f90 100644
    --- a/kernel/trace/trace_kprobe.c
    +++ b/kernel/trace/trace_kprobe.c
    @@ -988,10 +988,8 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
    struct trace_event_file *trace_file)
    {
    struct kprobe_trace_entry_head *entry;
    - struct ring_buffer_event *event;
    - struct ring_buffer *buffer;
    - int size, dsize, pc;
    - unsigned long irq_flags;
    + struct trace_event_buffer fbuffer;
    + int dsize;
    struct trace_event_call *call = trace_probe_event_call(&tk->tp);

    WARN_ON(call != trace_file->event_call);
    @@ -999,24 +997,26 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
    if (trace_trigger_soft_disabled(trace_file))
    return;

    - local_save_flags(irq_flags);
    - pc = preempt_count();
    + local_save_flags(fbuffer.flags);
    + fbuffer.pc = preempt_count();
    + fbuffer.trace_file = trace_file;

    dsize = __get_data_size(&tk->tp, regs);
    - size = sizeof(*entry) + tk->tp.size + dsize;

    - event = trace_event_buffer_lock_reserve(&buffer, trace_file,
    - call->event.type,
    - size, irq_flags, pc);
    - if (!event)
    + fbuffer.event =
    + trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
    + call->event.type,
    + sizeof(*entry) + tk->tp.size + dsize,
    + fbuffer.flags, fbuffer.pc);
    + if (!fbuffer.event)
    return;

    - entry = ring_buffer_event_data(event);
    + fbuffer.regs = regs;
    + entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
    entry->ip = (unsigned long)tk->rp.kp.addr;
    store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

    - event_trigger_unlock_commit_regs(trace_file, buffer, event,
    - entry, irq_flags, pc, regs);
    + trace_event_buffer_commit(&fbuffer);
    }

    static void
    @@ -1036,10 +1036,8 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
    struct trace_event_file *trace_file)
    {
    struct kretprobe_trace_entry_head *entry;
    - struct ring_buffer_event *event;
    - struct ring_buffer *buffer;
    - int size, pc, dsize;
    - unsigned long irq_flags;
    + struct trace_event_buffer fbuffer;
    + int dsize;
    struct trace_event_call *call = trace_probe_event_call(&tk->tp);

    WARN_ON(call != trace_file->event_call);
    @@ -1047,25 +1045,26 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
    if (trace_trigger_soft_disabled(trace_file))
    return;

    - local_save_flags(irq_flags);
    - pc = preempt_count();
    + local_save_flags(fbuffer.flags);
    + fbuffer.pc = preempt_count();
    + fbuffer.trace_file = trace_file;

    dsize = __get_data_size(&tk->tp, regs);
    - size = sizeof(*entry) + tk->tp.size + dsize;
    -
    - event = trace_event_buffer_lock_reserve(&buffer, trace_file,
    - call->event.type,
    - size, irq_flags, pc);
    - if (!event)
    + fbuffer.event =
    + trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
    + call->event.type,
    + sizeof(*entry) + tk->tp.size + dsize,
    + fbuffer.flags, fbuffer.pc);
    + if (!fbuffer.event)
    return;

    - entry = ring_buffer_event_data(event);
    + fbuffer.regs = regs;
    + entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
    entry->func = (unsigned long)tk->rp.kp.addr;
    entry->ret_ip = (unsigned long)ri->ret_addr;
    store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

    - event_trigger_unlock_commit_regs(trace_file, buffer, event,
    - entry, irq_flags, pc, regs);
    + trace_event_buffer_commit(&fbuffer);
    }

    static void
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