uprobes/tracing: Make uprobe_{trace,perf}_print() uretprobe-friendly

Change uprobe_trace_print() and uprobe_perf_print() to check
is_ret_probe() and fill ring_buffer_event accordingly.

Also change uprobe_trace_func() and uprobe_perf_func() to not
_print() if is_ret_probe() is true. Note that we keep ->handler()
nontrivial even for uretprobe, we need this for filtering and for
other potential extensions.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 72aa45e..0ed99a2 100644 (file)
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -516,15 +516,22 @@ static void uprobe_trace_print(struct trace_uprobe *tu,
        int size, i;
        struct ftrace_event_call *call = &tu->call;
 
-       size = SIZEOF_TRACE_ENTRY(false) + tu->size;
+       size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
        event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
-                                                 size, 0, 0);
+                                                 size + tu->size, 0, 0);
        if (!event)
                return;
 
        entry = ring_buffer_event_data(event);
-       entry->vaddr[0] = instruction_pointer(regs);
-       data = DATAOF_TRACE_ENTRY(entry, false);
+       if (is_ret_probe(tu)) {
+               entry->vaddr[0] = func;
+               entry->vaddr[1] = instruction_pointer(regs);
+               data = DATAOF_TRACE_ENTRY(entry, true);
+       } else {
+               entry->vaddr[0] = instruction_pointer(regs);
+               data = DATAOF_TRACE_ENTRY(entry, false);
+       }
+
        for (i = 0; i < tu->nr_args; i++)
                call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 
@@ -535,7 +542,8 @@ static void uprobe_trace_print(struct trace_uprobe *tu,
 /* uprobe handler */
 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
 {
-       uprobe_trace_print(tu, 0, regs);
+       if (!is_ret_probe(tu))
+               uprobe_trace_print(tu, 0, regs);
        return 0;
 }
 
@@ -784,7 +792,7 @@ static void uprobe_perf_print(struct trace_uprobe *tu,
        void *data;
        int size, rctx, i;
 
-       size = SIZEOF_TRACE_ENTRY(false);
+       size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
        size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32);
        if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
                return;
@@ -795,8 +803,15 @@ static void uprobe_perf_print(struct trace_uprobe *tu,
                goto out;
 
        ip = instruction_pointer(regs);
-       entry->vaddr[0] = ip;
-       data = DATAOF_TRACE_ENTRY(entry, false);
+       if (is_ret_probe(tu)) {
+               entry->vaddr[0] = func;
+               entry->vaddr[1] = ip;
+               data = DATAOF_TRACE_ENTRY(entry, true);
+       } else {
+               entry->vaddr[0] = ip;
+               data = DATAOF_TRACE_ENTRY(entry, false);
+       }
+
        for (i = 0; i < tu->nr_args; i++)
                call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 
@@ -812,7 +827,8 @@ static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
        if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
                return UPROBE_HANDLER_REMOVE;
 
-       uprobe_perf_print(tu, 0, regs);
+       if (!is_ret_probe(tu))
+               uprobe_perf_print(tu, 0, regs);
        return 0;
 }