[PATCH v2 2/2] uprobes/tracing: Fix uprobe_perf_open() on uprobe_apply() failure

[Oleg Nesterov <oleg@redhat.com>]

uprobe_perf_open()->uprobe_apply() can fail, but this error is wrongly
ignored. Change uprobe_perf_open() to do uprobe_perf_close() and return
the error code in this case.

Change uprobe_perf_close() to propogate the error from uprobe_apply()
as well, although it should not fail.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 kernel/trace/trace_uprobe.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 1ed0030..9aad3e2 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1020,7 +1020,7 @@ static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
 	write_unlock(&tu->filter.rwlock);
 
 	if (!done)
-		uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
+		return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
 
 	return 0;
 }
@@ -1028,6 +1028,7 @@ static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
 {
 	bool done;
+	int err;
 
 	write_lock(&tu->filter.rwlock);
 	if (event->hw.tp_target) {
@@ -1049,10 +1050,13 @@ static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
 	}
 	write_unlock(&tu->filter.rwlock);
 
-	if (!done)
-		uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
-
-	return 0;
+	err = 0;
+	if (!done) {
+		err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
+		if (err)
+			uprobe_perf_close(tu, event);
+	}
+	return err;
 }
 
 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
-- 
1.5.5.1