LoongArch: BPF: Zero-extend bpf_tail_call() index

commit eb71f5c433e1c6dff089b315881dec40a88a7baf upstream.

The bpf_tail_call() index should be treated as a u32 value. Let's
zero-extend it to avoid calling wrong BPF progs. See similar fixes
for x86 [1]) and arm64 ([2]) for more details.

  [1]: 90caccdd8c
  [2]: 16338a9b3a

Cc: stable@vger.kernel.org
Fixes: 5dc615520c ("LoongArch: Add BPF JIT support")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hengqi Chen
2025-12-31 15:19:20 +08:00
committed by Greg Kroah-Hartman
parent ad6ea65f15
commit 446c851e33

View File

@@ -226,6 +226,8 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn)
* goto out;
*/
tc_ninsn = insn ? ctx->offset[insn+1] - ctx->offset[insn] : ctx->offset[0];
emit_zext_32(ctx, a2, true);
off = offsetof(struct bpf_array, map.max_entries);
emit_insn(ctx, ldwu, t1, a1, off);
/* bgeu $a2, $t1, jmp_offset */