diff mbox series

[bpf-next,1/4] bpf: speed up stacksafe check

Message ID 20181212052854.4105971-2-ast@kernel.org
State Changes Requested, archived
Delegated to: BPF Maintainers
Headers show
Series bpf: improve verifier state analysis | expand

Commit Message

Alexei Starovoitov Dec. 12, 2018, 5:28 a.m. UTC 
don't check the same stack liveness condition 8 times.
once is enough.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 kernel/bpf/verifier.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8b511a4fe84a..d4db4727a50e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5147,9 +5147,11 @@  static bool stacksafe(struct bpf_func_state *old,
 	for (i = 0; i < old->allocated_stack; i++) {
 		spi = i / BPF_REG_SIZE;
 
-		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ))
+		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) {
+			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;