[PATCH arm64-next] net: bpf: arm64: fix module memory leak when JIT image build fails

[Daniel Borkmann]

On ARM64, when the BPF JIT compiler fills the JIT image body with
opcodes during translation of eBPF into ARM64 opcodes, we may fail
for several reasons during that phase: one being that we jump to
the notyet label for not yet supported eBPF instructions such as
BPF_ST. In that case we only free offsets, but not the actual
allocated target image where opcodes are being stored. Fix it by
calling module_free() on dismantle time in case of errors.

Signed-off-by: Daniel Borkmann <dborkman at redhat.com>
Cc: Zi Shen Lim <zlim.lnx at gmail.com>
Cc: Alexei Starovoitov <ast at plumgrid.com>
Cc: Will Deacon <will.deacon at arm.com>
---
 [ Compile-tested only. ]

 arch/arm64/net/bpf_jit_comp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 38c4296..7ae3354 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -651,8 +651,10 @@ void bpf_int_jit_compile(struct bpf_prog *prog)
 	build_prologue(&ctx);
 
 	ctx.body_offset = ctx.idx;
-	if (build_body(&ctx))
+	if (build_body(&ctx)) {
+		module_free(NULL, ctx.image);
 		goto out;
+	}
 
 	build_epilogue(&ctx);
 
-- 
1.9.3