The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e4a41c2c1fa916547e63440c73a51a5eb06247af Mon Sep 17 00:00:00 2001 From: Hou Tao houtao1@huawei.com Date: Fri, 31 Dec 2021 23:10:18 +0800 Subject: [PATCH] bpf, arm64: Use emit_addr_mov_i64() for BPF_PSEUDO_FUNC

The following error is reported when running "./test_progs -t for_each" under arm64:

bpf_jit: multi-func JIT bug 58 != 56 [...] JIT doesn't support bpf-to-bpf calls

The root cause is the size of BPF_PSEUDO_FUNC instruction increases from 2 to 3 after the address of called bpf-function is settled and there are two bpf-to-bpf calls in test_pkt_access. The generated instructions are shown below:

0x48: 21 00 C0 D2 movz x1, #0x1, lsl #32 0x4c: 21 00 80 F2 movk x1, #0x1

0x48: E1 3F C0 92 movn x1, #0x1ff, lsl #32 0x4c: 41 FE A2 F2 movk x1, #0x17f2, lsl #16 0x50: 81 70 9F F2 movk x1, #0xfb84

Fixing it by using emit_addr_mov_i64() for BPF_PSEUDO_FUNC, so the size of jited image will not change.

Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Signed-off-by: Hou Tao houtao1@huawei.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20211231151018.3781550-1-houtao1@huawei.com

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 07aad85848fa..e96d4d87291f 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -792,7 +792,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, u64 imm64;

imm64 = (u64)insn1.imm << 32 | (u32)imm; - emit_a64_mov_i64(dst, imm64, ctx); + if (bpf_pseudo_func(insn)) + emit_addr_mov_i64(dst, imm64, ctx); + else + emit_a64_mov_i64(dst, imm64, ctx);

return 1; }