[PATCH bpf v9 8/8] powerpc64/bpf: fix percpu private stack leak on JIT failure

[adubey@linux.ibm.com]

From: Abhishek Dubey <adubey@linux.ibm.com>

The existing conditional statement in bpf_int_jit_compile() frees the
percpu private stack at out_addrs only when the image buffer was never
allocated.

If bpf_jit_build_body() fails during a code-generation pass, the
image buffer has already been allocated, so !image is false and the
percpu stack is not freed.

Because JIT compilation failed, fp->jited remains at 0. The subsequent
bpf_jit_free() path only frees priv_stack_ptr when fp->jited is set, so
freeing is skipped here too, leaking the percpu allocation.

Fix implements freeing the private stack whenever fp->jited was not set,
i.e. compilation did not succeed, instead of keying off !image. !fp->jited
already covers the !image case, since image is only NULL on early-failure
paths where fp->jited is likewise 0.

Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/bpf/20260616135426.A06B71F000E9@smtp.kernel.org
Fixes: 156d985123b6 ("powerpc64/bpf: Implement JIT support for private stack")
Cc: stable@vger.kernel.org
Signed-off-by: Abhishek Dubey <adubey@linux.ibm.com>
---
 arch/powerpc/net/bpf_jit_comp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 171cb6017259..46bbfb6be613 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -403,7 +403,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_pr
 				(void *)fimage + FUNCTION_DESCR_SIZE);
 
 out_addrs:
-		if (!image && priv_stack_ptr) {
+		if (!fp->jited && priv_stack_ptr) {
 			fp->aux->priv_stack_ptr = NULL;
 			free_percpu(priv_stack_ptr);
 		}
-- 
2.52.0