On Sun, Mar 26, 2023 at 11:21 PM Xu Kuohai <xukuohai@xxxxxxxxxxxxxxx> wrote:
>
> On 3/27/2023 11:20 AM, Andrii Nakryiko wrote:
> > On Sun, Mar 26, 2023 at 7:45 PM Xu Kuohai <xukuohai@xxxxxxxxxxxxxxx> wrote:
> >>
> >> From: Xu Kuohai <xukuohai@xxxxxxxxxx>
> >>
> >> The two infinite loop bound check cases added by commit
> >> 1a3148fc171f ("selftests/bpf: Check when bounds are not in the 32-bit range")
> >> take a long time to execute but don't add much value.
> >>
> >> Remove them to reduce run time of test_verifier.
> >
> > Summary: 2042 PASSED, 0 SKIPPED, 1 FAILED
> >
> > real 0m4.780s
> > user 0m0.458s
> > sys 0m3.871s
> >
> >
> > 5 seconds isn't such a long time, especially when we compare it to
> > test_progs (even with parallelization).
> >
>
> Well, I actually don't know if it is "long time".
>
> This patch was sent to address Alexei's concern about the run time
> of test_verifier in mail [1].
> These infinite loops don't add much value to the actual test.
> Please rewrite them without infinite loops.
Alexei asked to improve the test, not to just remove it, if I
understand correctly. If the test is there, presumably it's useful. If
it can be implemented better, let's do that. Just removing the test
seems like a wrong move.
>
> [1] https://lore.kernel.org/bpf/20230322213056.2470-1-daniel@xxxxxxxxxxxxx/T/#mb3d6363a693ccd63d416d9d787db17f8fdcb8442
>
> >>
> >> Fixes: 1a3148fc171f ("selftests/bpf: Check when bounds are not in the 32-bit range")
> >> Signed-off-by: Xu Kuohai <xukuohai@xxxxxxxxxx>
> >> ---
> >> tools/testing/selftests/bpf/verifier/bounds.c | 50 -------------------
> >> 1 file changed, 50 deletions(-)
> >>
> >> diff --git a/tools/testing/selftests/bpf/verifier/bounds.c b/tools/testing/selftests/bpf/verifier/bounds.c
> >> index 74b1917d4208..515a8222f08f 100644
> >> --- a/tools/testing/selftests/bpf/verifier/bounds.c
> >> +++ b/tools/testing/selftests/bpf/verifier/bounds.c
> >> @@ -777,31 +777,6 @@
> >> .result = ACCEPT,
> >> .prog_type = BPF_PROG_TYPE_XDP,
> >> },
> >> -{
> >> - "bound check with JMP_JSLT for crossing 64-bit signed boundary",
> >> - .insns = {
> >> - BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
> >> - BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data_end)),
> >> - BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
> >> - BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 1),
> >> - BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 8),
> >> -
> >> - BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
> >> - BPF_LD_IMM64(BPF_REG_0, 0x7fffffffffffff10),
> >> - BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
> >> -
> >> - BPF_LD_IMM64(BPF_REG_0, 0x8000000000000000),
> >> - BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
> >> - /* r1 signed range is [S64_MIN, S64_MAX] */
> >> - BPF_JMP_REG(BPF_JSLT, BPF_REG_0, BPF_REG_1, -2),
> >> -
> >> - BPF_MOV64_IMM(BPF_REG_0, 0),
> >> - BPF_EXIT_INSN(),
> >> - },
> >> - .errstr = "BPF program is too large",
> >> - .result = REJECT,
> >> - .prog_type = BPF_PROG_TYPE_XDP,
> >> -},
> >> {
> >> "bound check for loop upper bound greater than U32_MAX",
> >> .insns = {
> >> @@ -849,28 +824,3 @@
> >> .result = ACCEPT,
> >> .prog_type = BPF_PROG_TYPE_XDP,
> >> },
> >> -{
> >> - "bound check with JMP32_JSLT for crossing 32-bit signed boundary",
> >> - .insns = {
> >> - BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
> >> - BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data_end)),
> >> - BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
> >> - BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 1),
> >> - BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 6),
> >> -
> >> - BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
> >> - BPF_MOV32_IMM(BPF_REG_0, 0x7fffff10),
> >> - BPF_ALU32_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
> >> -
> >> - BPF_MOV32_IMM(BPF_REG_0, 0x80000000),
> >> - BPF_ALU32_IMM(BPF_ADD, BPF_REG_0, 1),
> >> - /* r1 signed range is [S32_MIN, S32_MAX] */
> >> - BPF_JMP32_REG(BPF_JSLT, BPF_REG_0, BPF_REG_1, -2),
> >> -
> >> - BPF_MOV64_IMM(BPF_REG_0, 0),
> >> - BPF_EXIT_INSN(),
> >> - },
> >> - .errstr = "BPF program is too large",
> >> - .result = REJECT,
> >> - .prog_type = BPF_PROG_TYPE_XDP,
> >> -},
> >> --
> >> 2.30.2
> >>
> > .
>
