[PATCH] trace: Avoid memory leak in predicate_parse()

[Tomas Bortoli]

In case of errors, predicate_parse() goes to the out_free label
to free memory and to return an error code.

However, predicate_parse() does not free the predicates of the
temporary prog_stack array, thence leaking them.

Signed-off-by: Tomas Bortoli <tomasbort...@gmail.com>
Reported-by: syzbot+6b8e0fb820e570c59...@syzkaller.appspotmail.com
---
 kernel/trace/trace_events_filter.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_filter.c 
b/kernel/trace/trace_events_filter.c
index 05a66493a164..ecfa6f0f1c7e 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -427,7 +427,7 @@ predicate_parse(const char *str, int nr_parens, int 
nr_preds,
        op_stack = kmalloc_array(nr_parens, sizeof(*op_stack), GFP_KERNEL);
        if (!op_stack)
                return ERR_PTR(-ENOMEM);
-       prog_stack = kmalloc_array(nr_preds, sizeof(*prog_stack), GFP_KERNEL);
+       prog_stack = kcalloc(nr_preds, sizeof(*prog_stack), GFP_KERNEL);
        if (!prog_stack) {
                parse_error(pe, -ENOMEM, 0);
                goto out_free;
@@ -578,6 +578,8 @@ predicate_parse(const char *str, int nr_parens, int 
nr_preds,
 out_free:
        kfree(op_stack);
        kfree(inverts);
+       for (i = 0; prog_stack[i].pred; i++)
+               kfree(prog_stack[i].pred);
        kfree(prog_stack);
        return ERR_PTR(ret);
 }
-- 
2.11.0