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bpf: fix liveness propagation to parent in spilled stack slots 

Using parent->regs[] when propagating REG_LIVE_READ for spilled regs
doesn't work since parent->regs[] denote the set of normal registers
but not spilled ones. Propagate to the correct regs.

Fixes: dc503a8ad9 ("bpf/verifier: track liveness for pruning")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2017-08-17 14:59:40 +02:00 committed by David S. Miller
parent fd07a62d58
commit 1ab2de2bfe
1 changed files with 1 additions and 1 deletions
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2
kernel/bpf/verifier.c
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@ -3460,7 +3460,7 @@ static bool do_propagate_liveness(const struct bpf_verifier_state *state,
if (parent->spilled_regs[i].live & REG_LIVE_READ)
continue;
if (state->spilled_regs[i].live == REG_LIVE_READ) {
parent->regs[i].live |= REG_LIVE_READ;
parent->spilled_regs[i].live |= REG_LIVE_READ;
touched = true;
}
}