6.18-stable review patch. If anyone has any objections, please let me know.
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From: Chenghao Duan duanchenghao@kylinos.cn
commit d314e1f48260cef3f869e3edc02a02c8a48b08e1 upstream.
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 duanchenghao@kylinos.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/net/bpf_jit.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -139,6 +139,7 @@ static void build_prologue(struct jit_ct 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);