[PATCH bpf 1/2] bpf: Do not release trampoline image in case off unregister error

[Jiri Olsa <jolsa@kernel.org>]

If unregister_fentry fails we still have trampoline image attached
to a function, so releasing it could trigger crash. Releasing the
trampoline image only when the unregister succeeds.

Cc: stable@vger.kernel.org
Fixes: e21aa341785c ("bpf: Fix fexit trampoline.")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/bpf/trampoline.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index f02254a21585..01082ecc5c4f 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -618,8 +618,10 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut
 
 	if (total == 0) {
 		err = unregister_fentry(tr, orig_flags, tr->cur_image->image);
-		bpf_tramp_image_put(tr->cur_image);
-		tr->cur_image = NULL;
+		if (!err) {
+			bpf_tramp_image_put(tr->cur_image);
+			tr->cur_image = NULL;
+		}
 		goto out;
 	}
 
-- 
2.53.0