Commit dfb2d4c6 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

bpf: set 'changed' status if propagate_liveness() did any updates 



Add an out parameter to `propagate_liveness()` to record whether any
new liveness bits were set during its execution.

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250611200836.4135542-6-eddyz87@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 23b37d61

kernel/bpf/verifier.c

+7 −2
Original line number Diff line number Diff line
@@ -18856,12 +18856,15 @@ static int propagate_liveness_reg(struct bpf_verifier_env *env, 
 */

static int propagate_liveness(struct bpf_verifier_env *env,

			      const struct bpf_verifier_state *vstate,

			      struct bpf_verifier_state *vparent)

			      struct bpf_verifier_state *vparent,

			      bool *changed)

{

	struct bpf_reg_state *state_reg, *parent_reg;

	struct bpf_func_state *state, *parent;

	int i, frame, err = 0;

	bool tmp;









	changed = changed ?: &tmp;









	if (vparent->curframe != vstate->curframe) {









		WARN(1, "propagate_live: parent frame %d current frame %d\n",









		     vparent->curframe, vstate->curframe);








@@ -18880,6 +18883,7 @@ static int propagate_liveness(struct bpf_verifier_env *env,







						     &parent_reg[i]);









			if (err < 0)









				return err;









			*changed |= err > 0;









			if (err == REG_LIVE_READ64)









				mark_insn_zext(env, &parent_reg[i]);









		}








@@ -18891,6 +18895,7 @@ static int propagate_liveness(struct bpf_verifier_env *env,







			state_reg = &state->stack[i].spilled_ptr;









			err = propagate_liveness_reg(env, state_reg,









						     parent_reg);









			*changed |= err > 0;









			if (err < 0)









				return err;









		}








@@ -19266,7 +19271,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)







			 * they'll be immediately forgotten as we're pruning









			 * this state and will pop a new one.









			 */









			err = propagate_liveness(env, &sl->state, cur);









			err = propagate_liveness(env, &sl->state, cur, NULL);

















			/* if previous state reached the exit with precision and









			 * current state is equivalent to it (except precision marks)