Re: [PATCH bpf v1 1/2] bpf: sync_linked_regs() must preserve subreg_def

[Eduard Zingerman <eddyz87@xxxxxxxxx>]

On Wed, 2024-09-25 at 11:44 +0200, Daniel Borkmann wrote:

[...]

> Do we have a Fixes tag for stable?

I think this bug persisted from the beginning:
75748837b7e5 ("bpf: Propagate scalar ranges through register assignments.")

E.g. here is original find_equal_scalars():
static void find_equal_scalars(struct bpf_verifier_state *vstate,
			       struct bpf_reg_state *known_reg)
{
	...
	struct bpf_reg_state *reg;
	...
				*reg = *known_reg;
	...
}

And bpf_reg_state for 75748837b7e5 has subreg_def as a member.

I can post v2 with this "Fixes" tag if you'd like.