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Wed, 16 Nov 2022 05:27:47 -0500 X-MC-Unique: mUeJQgfvOUWRJd96rWHDcg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 547AE86F13B; Wed, 16 Nov 2022 10:27:45 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.216]) by smtp.corp.redhat.com (Postfix) with ESMTP id C5D9B20290A6; Wed, 16 Nov 2022 10:27:38 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, Linus Torvalds , Andrew Morton , Jason Gunthorpe , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit , Vlastimil Babka , Matthew Wilcox , Mike Kravetz , Muchun Song , Shuah Khan , Lucas Stach , David Airlie , Oded Gabbay , Arnd Bergmann , Christoph Hellwig , Alex Williamson , David Hildenbrand Subject: [PATCH mm-unstable v1 03/20] selftests/vm: cow: R/O long-term pinning reliability tests for non-anon pages Date: Wed, 16 Nov 2022 11:26:42 +0100 Message-Id: <20221116102659.70287-4-david@redhat.com> In-Reply-To: <20221116102659.70287-1-david@redhat.com> References: <20221116102659.70287-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221116_022754_386251_38BA4CD6 X-CRM114-Status: GOOD ( 16.37 ) X-Spam-Score: -0.4 (/) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Let's test whether R/O long-term pinning is reliable for non-anonymous memory: when R/O long-term pinning a page, the expectation is that we break COW early before pinning, such that actual write acce [...] Content analysis details: (-0.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_MSPIKE_H2 RBL: Average reputation (+2) [170.10.129.124 listed in wl.mailspike.net] -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [170.10.129.124 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.0 SPF_NONE SPF: sender does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.2 DKIMWL_WL_HIGH DKIMwl.org - High trust sender X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Let's test whether R/O long-term pinning is reliable for non-anonymous memory: when R/O long-term pinning a page, the expectation is that we break COW early before pinning, such that actual write access via the page tables won't break COW later and end up replacing the R/O-pinned page in the page table. Consequently, R/O long-term pinning in private mappings would only target exclusive anonymous pages. For now, all tests fail: # [RUN] R/O longterm GUP pin ... with shared zeropage not ok 151 Longterm R/O pin is reliable # [RUN] R/O longterm GUP pin ... with memfd not ok 152 Longterm R/O pin is reliable # [RUN] R/O longterm GUP pin ... with tmpfile not ok 153 Longterm R/O pin is reliable # [RUN] R/O longterm GUP pin ... with huge zeropage not ok 154 Longterm R/O pin is reliable # [RUN] R/O longterm GUP pin ... with memfd hugetlb (2048 kB) not ok 155 Longterm R/O pin is reliable # [RUN] R/O longterm GUP pin ... with memfd hugetlb (1048576 kB) not ok 156 Longterm R/O pin is reliable # [RUN] R/O longterm GUP-fast pin ... with shared zeropage not ok 157 Longterm R/O pin is reliable # [RUN] R/O longterm GUP-fast pin ... with memfd not ok 158 Longterm R/O pin is reliable # [RUN] R/O longterm GUP-fast pin ... with tmpfile not ok 159 Longterm R/O pin is reliable # [RUN] R/O longterm GUP-fast pin ... with huge zeropage not ok 160 Longterm R/O pin is reliable # [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (2048 kB) not ok 161 Longterm R/O pin is reliable # [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (1048576 kB) not ok 162 Longterm R/O pin is reliable Signed-off-by: David Hildenbrand --- tools/testing/selftests/vm/cow.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/vm/cow.c b/tools/testing/selftests/vm/cow.c index fb07bd44529c..73e05b52c49e 100644 --- a/tools/testing/selftests/vm/cow.c +++ b/tools/testing/selftests/vm/cow.c @@ -561,6 +561,7 @@ static void test_iouring_fork(char *mem, size_t size) #endif /* LOCAL_CONFIG_HAVE_LIBURING */ enum ro_pin_test { + RO_PIN_TEST, RO_PIN_TEST_SHARED, RO_PIN_TEST_PREVIOUSLY_SHARED, RO_PIN_TEST_RO_EXCLUSIVE, @@ -593,6 +594,8 @@ static void do_test_ro_pin(char *mem, size_t size, enum ro_pin_test test, } switch (test) { + case RO_PIN_TEST: + break; case RO_PIN_TEST_SHARED: case RO_PIN_TEST_PREVIOUSLY_SHARED: /* @@ -1193,6 +1196,16 @@ static void test_cow(char *mem, const char *smem, size_t size) free(old); } +static void test_ro_pin(char *mem, const char *smem, size_t size) +{ + do_test_ro_pin(mem, size, RO_PIN_TEST, false); +} + +static void test_ro_fast_pin(char *mem, const char *smem, size_t size) +{ + do_test_ro_pin(mem, size, RO_PIN_TEST, true); +} + static void run_with_zeropage(non_anon_test_fn fn, const char *desc) { char *mem, *smem, tmp; @@ -1433,7 +1446,7 @@ struct non_anon_test_case { }; /* - * Test cases that target any pages in private mappings that are non anonymous: + * Test cases that target any pages in private mappings that are not anonymous: * pages that may get shared via COW ndependent of fork(). This includes * the shared zeropage(s), pagecache pages, ... */ @@ -1446,6 +1459,19 @@ static const struct non_anon_test_case non_anon_test_cases[] = { "Basic COW", test_cow, }, + /* + * Take a R/O longterm pin. When modifying the page via the page table, + * the page content change must be visible via the pin. + */ + { + "R/O longterm GUP pin", + test_ro_pin, + }, + /* Same as above, but using GUP-fast. */ + { + "R/O longterm GUP-fast pin", + test_ro_fast_pin, + }, }; static void run_non_anon_test_case(struct non_anon_test_case const *test_case)