From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 17 Aug 2017 14:59:40 +0200
Subject: bpf: fix liveness propagation to parent in spilled stack slots
Patch-mainline: v4.14-rc1
Git-commit: 1ab2de2bfed3ab2073ed1e7afa2b1134930d2b70
References: bsc#1056787

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: dc503a8ad984 ("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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 kernel/bpf/verifier.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3456,7 +3456,7 @@ static bool do_propagate_liveness(const
 		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;
 		}
 	}