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tracing/uprobe: Add multi-probe per uprobe event support

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Allow user to define several probes on one uprobe event.
Note that this only support appending method. So deleting
event will delete all probes on the event.

Link: http://lkml.kernel.org/r/156095687876.28024.13840331032234992863.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2019-06-20 00:07:58 +09:00 committed by Steven Rostedt (VMware)
parent ca89bc071d
commit 41af3cf587
2 changed files with 43 additions and 19 deletions
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2
kernel/trace/trace.c
View File

@ -4823,7 +4823,7 @@ static const char readme_msg[] =
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
#ifdef CONFIG_UPROBE_EVENTS
" uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
" uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)

60
kernel/trace/trace_uprobe.c
View File

@ -364,15 +364,32 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
{
int ret;
if (trace_probe_has_sibling(&tu->tp))
goto unreg;
ret = unregister_uprobe_event(tu);
if (ret)
return ret;
unreg:
dyn_event_remove(&tu->devent);
trace_probe_unlink(&tu->tp);
free_trace_uprobe(tu);
return 0;
}
static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)
{
int ret;
/* Append to existing event */
ret = trace_probe_append(&tu->tp, &to->tp);
if (!ret)
dyn_event_add(&tu->devent);
return ret;
}
/*
* Uprobe with multiple reference counter is not allowed. i.e.
* If inode and offset matches, reference counter offset *must*
@ -382,25 +399,21 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
* as the new one does not conflict with any other existing
* ones.
*/
static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
static int validate_ref_ctr_offset(struct trace_uprobe *new)
{
struct dyn_event *pos;
struct trace_uprobe *tmp, *old = NULL;
struct trace_uprobe *tmp;
struct inode *new_inode = d_real_inode(new->path.dentry);
old = find_probe_event(trace_probe_name(&new->tp),
trace_probe_group_name(&new->tp));
for_each_trace_uprobe(tmp, pos) {
if ((old ? old != tmp : true) &&
new_inode == d_real_inode(tmp->path.dentry) &&
if (new_inode == d_real_inode(tmp->path.dentry) &&
new->offset == tmp->offset &&
new->ref_ctr_offset != tmp->ref_ctr_offset) {
pr_warn("Reference counter offset mismatch.");
return ERR_PTR(-EINVAL);
return -EINVAL;
}
}
return old;
return 0;
}
/* Register a trace_uprobe and probe_event */
@ -411,18 +424,29 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
mutex_lock(&event_mutex);
/* register as an event */
old_tu = find_old_trace_uprobe(tu);
if (IS_ERR(old_tu)) {
ret = PTR_ERR(old_tu);
ret = validate_ref_ctr_offset(tu);
if (ret)
goto end;
}
/* register as an event */
old_tu = find_probe_event(trace_probe_name(&tu->tp),
trace_probe_group_name(&tu->tp));
if (old_tu) {
/* delete old event */
ret = unregister_trace_uprobe(old_tu);
if (ret)
goto end;
if (is_ret_probe(tu) != is_ret_probe(old_tu)) {
trace_probe_log_set_index(0);
trace_probe_log_err(0, DIFF_PROBE_TYPE);
ret = -EEXIST;
} else {
ret = trace_probe_compare_arg_type(&tu->tp, &old_tu->tp);
if (ret) {
/* Note that argument starts index = 2 */
trace_probe_log_set_index(ret + 1);
trace_probe_log_err(0, DIFF_ARG_TYPE);
ret = -EEXIST;
} else
ret = append_trace_uprobe(tu, old_tu);
}
goto end;
}
ret = register_uprobe_event(tu);