linux-kernel - [PATCH v2 1/1] riscv: bpf: Fix uninitialized symbol 'retval

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Message-Id: <20250922062244.822937-2-duanchenghao@kylinos.cn>
Date: Mon, 22 Sep 2025 14:22:44 +0800
From: Chenghao Duan <duanchenghao@...inos.cn>
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Subject: [PATCH v2 1/1] riscv: bpf: Fix uninitialized symbol 'retval_off'

In the __arch_prepare_bpf_trampoline() function, retval_off is only
meaningful when save_ret is true, so the current logic is correct.
However, in the original logic, retval_off is only initialized under
certain conditions; for example, in the fmod_ret logic, the compiler is
not aware that the flags of the fmod_ret program (prog) have set
BPF_TRAMP_F_CALL_ORIG, which results in an uninitialized symbol
compilation warning.

So initialize retval_off unconditionally to fix it.

Signed-off-by: Chenghao Duan <duanchenghao@...inos.cn>
---
 arch/riscv/net/bpf_jit_comp64.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 9883a55d61b5..8475a8ab5715 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1079,10 +1079,9 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
 	stack_size += 16;
 
 	save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
-	if (save_ret) {
+	if (save_ret)
 		stack_size += 16; /* Save both A5 (BPF R0) and A0 */
-		retval_off = stack_size;
-	}
+	retval_off = stack_size;
 
 	stack_size += nr_arg_slots * 8;
 	args_off = stack_size;
-- 
2.25.1