From: Hou Tao <houtao1@huawei.com> mainline inclusion from mainline commit 6801cf7890f2ed8fcc14859b47501f8ee7a58ec7 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IDC9YK Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... -------------------------------- As reported by Byeonguk, the bad_words test in verifier_bits_iter.c occasionally fails on s390 host. Quoting Ilya's explanation: s390 kernel runs in a completely separate address space, there is no user/kernel split at TASK_SIZE. The same address may be valid in both the kernel and the user address spaces, there is no way to tell by looking at it. The config option related to this property is ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE. Also, unfortunately, 0 is a valid address in the s390 kernel address space. Fix the issue by using -4095 as the bad address for bits iterator, as suggested by Ilya. Verify that bpf_iter_bits_new() returns -EINVAL for NULL address and -EFAULT for bad address. Fixes: ebafc1e535db ("selftests/bpf: Add three test cases for bits_iter") Reported-by: Byeonguk Jeong <jungbu2855@gmail.com> Closes: https://lore.kernel.org/bpf/ZycSXwjH4UTvx-Cn@ub22/ Signed-off-by: Hou Tao <houtao1@huawei.com> Acked-by: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/r/20241105043057.3371482-1-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Zicheng Qu <quzicheng@huawei.com> --- .../selftests/bpf/progs/verifier_bits_iter.c | 32 ++++++++++++++++--- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/verifier_bits_iter.c b/tools/testing/selftests/bpf/progs/verifier_bits_iter.c index e1421d846ac8..b6b018baed46 100644 --- a/tools/testing/selftests/bpf/progs/verifier_bits_iter.c +++ b/tools/testing/selftests/bpf/progs/verifier_bits_iter.c @@ -57,9 +57,15 @@ __description("null pointer") __success __retval(0) int null_pointer(void) { - int nr = 0; + struct bpf_iter_bits iter; + int err, nr = 0; int *bit; + err = bpf_iter_bits_new(&iter, NULL, 1); + bpf_iter_bits_destroy(&iter); + if (err != -EINVAL) + return 1; + bpf_for_each(bits, bit, NULL, 1) nr++; return nr; @@ -194,15 +200,33 @@ __description("bad words") __success __retval(0) int bad_words(void) { - void *bad_addr = (void *)(3UL << 30); - int nr = 0; + void *bad_addr = (void *)-4095; + struct bpf_iter_bits iter; + volatile int nr; int *bit; + int err; + + err = bpf_iter_bits_new(&iter, bad_addr, 1); + bpf_iter_bits_destroy(&iter); + if (err != -EFAULT) + return 1; + nr = 0; bpf_for_each(bits, bit, bad_addr, 1) nr++; + if (nr != 0) + return 2; + err = bpf_iter_bits_new(&iter, bad_addr, 4); + bpf_iter_bits_destroy(&iter); + if (err != -EFAULT) + return 3; + + nr = 0; bpf_for_each(bits, bit, bad_addr, 4) nr++; + if (nr != 0) + return 4; - return nr; + return 0; } -- 2.34.1