btf_distill_func_proto() accepts a function argument up to 16 bytes, so a 128-bit scalar such as __int128 reaches the x86 trampoline with arg_size == 16. But the current implementation assumes an __int128 argument only needs one register, so the register save area is under-allocated and save_args() overwrites adjacent stack slots. Compute the register count from arg_size for all arguments to fix it. Fixes: a9c5ad31fbdc ("bpf: x86: Support in-register struct arguments in trampoline programs") Acked-by: Leon Hwang Signed-off-by: Yonghong Song --- arch/x86/net/bpf_jit_comp.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index b2feec81e231..01e7ce569c1e 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -3369,11 +3369,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im WARN_ON_ONCE((flags & BPF_TRAMP_F_INDIRECT) && (flags & ~(BPF_TRAMP_F_INDIRECT | BPF_TRAMP_F_RET_FENTRY_RET))); - /* extra registers for struct arguments */ - for (i = 0; i < m->nr_args; i++) { - if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG) - nr_regs += (m->arg_size[i] + 7) / 8 - 1; - } + for (i = 0; i < m->nr_args; i++) + nr_regs += (m->arg_size[i] + 7) / 8 - 1; /* x86-64 supports up to MAX_BPF_FUNC_ARGS arguments. 1-6 * are passed through regs, the remains are through stack. -- 2.53.0-Meta