From 98b74b6ba60ce846484df9fc756b45475d02498a Mon Sep 17 00:00:00 2001 From: Chenghao Duan Date: Wed, 31 Dec 2025 15:19:20 +0800 Subject: [PATCH] LoongArch: BPF: Save return address register ra to t0 before trampoline Modify the build_prologue() function to ensure the return address register ra is saved to t0 before entering trampoline operations. This change ensures the accurate return address handling when a BPF program calls another BPF program, preventing errors in the BPF-to-BPF call chain. Cc: stable@vger.kernel.org Fixes: 677e6123e3d2 ("LoongArch: BPF: Disable trampoline for kernel module function trace") Signed-off-by: Chenghao Duan Signed-off-by: Huacai Chen Signed-off-by: maoxiaochuan --- arch/loongarch/net/bpf_jit.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index 4be851519..1d09c0d80 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -139,6 +139,7 @@ static void build_prologue(struct jit_ctx *ctx) stack_adjust = round_up(stack_adjust, 16); stack_adjust += bpf_stack_adjust; + move_reg(ctx, LOONGARCH_GPR_T0, LOONGARCH_GPR_RA); /* Reserve space for the move_imm + jirl instruction */ for (i = 0; i < LOONGARCH_LONG_JUMP_NINSNS; i++) emit_insn(ctx, nop);