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bpf: remove redundant REG_LIVE_READ check in stacksafe()

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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: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-3-c3cd27bacc60@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Eduard Zingerman
2025-09-18 19:18:36 -07:00
committed by Alexei Starovoitov
parent 6cd21eb9ad
commit 12a23f93a5
1 changed files with 0 additions and 7 deletions
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7
kernel/bpf/verifier.c
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@@ -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;