From 19e2dbb7dd978d24505e918ac54d6f7dfdc88b1d Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 13 Dec 2018 11:42:33 -0800 Subject: bpf: improve stacksafe state comparison "if (old->allocated_stack > cur->allocated_stack)" check is too conservative. In some cases explored stack could have allocated more space, but that stack space was not live. The test case improves from 19 to 15 processed insns and improvement on real programs is significant as well: before after bpf_lb-DLB_L3.o 1940 1831 bpf_lb-DLB_L4.o 3089 3029 bpf_lb-DUNKNOWN.o 1065 1064 bpf_lxc-DDROP_ALL.o 28052 26309 bpf_lxc-DUNKNOWN.o 35487 33517 bpf_netdev.o 10864 9713 bpf_overlay.o 6643 6184 bpf_lcx_jit.o 38437 37335 Signed-off-by: Alexei Starovoitov Acked-by: Edward Cree Acked-by: Jakub Kicinski Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_verifier.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'tools/testing/selftests/bpf') diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 82359cdbc805..f9de7fe0c26d 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -13647,6 +13647,28 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, .result = ACCEPT, }, + { + "allocated_stack", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_1), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32), + BPF_ALU64_REG(BPF_MOV, BPF_REG_7, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, -8), + BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, -8), + BPF_STX_MEM(BPF_B, BPF_REG_10, BPF_REG_7, -9), + BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_10, -9), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .result_unpriv = ACCEPT, + .insn_processed = 15, + }, { "reference tracking in call: free reference in subprog and outside", .insns = { -- cgit v1.2.3-59-g8ed1b