Commit 12a23f93 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

bpf: remove redundant REG_LIVE_READ check in stacksafe() 



stacksafe() is called in exact == NOT_EXACT mode only for states that
had been porcessed by clean_verifier_states(). The latter replaces
dead stack spills with a series of STACK_INVALID masks. Such masks are
already handled by stacksafe().

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-3-c3cd27bacc60@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 6cd21eb9

kernel/bpf/verifier.c

+0 −7
Original line number Diff line number Diff line
@@ -18785,13 +18785,6 @@ static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old, 
		     cur->stack[spi].slot_type[i % BPF_REG_SIZE]))

			return false;









		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)









		    && exact == NOT_EXACT) {









			i += BPF_REG_SIZE - 1;









			/* explored state didn't use this */









			continue;









		}

















		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)









			continue;