[PATCH v2 09/13] tracing/uprobes: Fix memory leak of tail in __trace_uprobe_create()

["Masami Hiramatsu (Google)" <mhiramat@kernel.org>]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

When generating a default event name in __trace_uprobe_create(), tail is
allocated with kstrdup() without __free(kfree). If the subsequent
kmalloc() for buf fails, the function returns -ENOMEM immediately and
leaks tail.

Declare tail with __free(kfree) so it is automatically freed on all
exit paths.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/sashiko-outbox-204240@kernel.org/
Fixes: 97e8230f89a3 ("tracing: uprobe-event: Allocate string buffers from heap")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
 - Newly added.
---
 kernel/trace/trace_uprobe.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 14ac52aebe34..fb7991543db7 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -701,7 +701,7 @@ static int __trace_uprobe_create(int argc, const char **argv)
 	}
 
 	if (!event) {
-		char *tail;
+		char *tail __free(kfree) = NULL;
 		char *ptr;
 
 		tail = kstrdup(kbasename(filename), GFP_KERNEL);
@@ -717,7 +717,6 @@ static int __trace_uprobe_create(int argc, const char **argv)
 			return -ENOMEM;
 		snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
 		event = buf;
-		kfree(tail);
 	}
 
 	argc -= 2;