From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AA3310962 for ; Mon, 25 Mar 2024 18:29:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711391343; cv=none; b=KHd1ArYw6DI8HgVpz4j8qi6DIYXsPiTP+vGJv1XnYLjtlIZqaIpbqXTzOS4apLKBMNCmW11ahbLZaNEL522sT7lpPNHaJ1TLjlQquAuS8F03XkdO84MxWQ62V3G5XIzSTEtHT4uYqX4Y/xapo1qHllVLJIs8JYxguZOr7/9Kcs0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711391343; c=relaxed/simple; bh=JcUq0dJat6AGxHO1gr/JQr4B+A992I9Kbcs5vMoU5r4=; h=Date:To:From:Subject:Message-Id; b=AWH9FbF71R++mGiFTaLJoZbycZeOgxUi9upwqjyDuoJq66jwE+UCeQaVdiWoyC5l1To34R1dsinsDcEZUsX3ZH5uk6zgguSU4qEpcIG+xZWeZ0uRD9rXmRwCSlF7UJp1rFBHiU9ghTOdv/m7BmkuaNwr0coXBFHfLSj0MXyA8dg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=unvz6mgP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="unvz6mgP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F211FC433C7; Mon, 25 Mar 2024 18:29:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1711391343; bh=JcUq0dJat6AGxHO1gr/JQr4B+A992I9Kbcs5vMoU5r4=; h=Date:To:From:Subject:From; b=unvz6mgP/b6JtA9cxteDaZ8ovV+2A0cBQ1UVAx4evO0o5CKovzfA1UOgwuawAARnR HCIkQyGQo6vkNf/bYea7hu6lvSv5FeA1HXpRsWR5wOqBFar+a4UGftwlbc4acm321x wXPxec+W2slMKvKQZDB3YcX1DmD+sCdlZQymUP0k= Date: Mon, 25 Mar 2024 11:29:02 -0700 To: mm-commits@vger.kernel.org,xrivendell7@gmail.com,samsun1006219@gmail.com,rppt@kernel.org,mszeredi@redhat.com,lstoakes@gmail.com,david@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-memfd_secret-add-vmsplice-test.patch added to mm-unstable branch Message-Id: <20240325182902.F211FC433C7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/memfd_secret: add vmsplice() test has been added to the -mm mm-unstable branch. Its filename is selftests-memfd_secret-add-vmsplice-test.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-memfd_secret-add-vmsplice-test.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: David Hildenbrand Subject: selftests/memfd_secret: add vmsplice() test Date: Mon, 25 Mar 2024 14:41:13 +0100 Let's add a simple reproducer for a scneario where GUP-fast could succeed on secretmem folios, making vmsplice() succeed instead of failing. The reproducer is based on a reproducer [1] by Miklos Szeredi. Perform the ftruncate() only once, and check the return value. For some reason, vmsplice() reliably fails (making the test succeed) when we move the test_vmsplice() call after test_process_vm_read() / test_ptrace(). Properly cleaning up in test_remote_access(), which is not part of this change, won't change that behavior. Therefore, run the vmsplice() test for now first -- something is a bit off once we involve fork(). [1] https://lkml.kernel.org/r/CAJfpegt3UCsMmxd0taOY11Uaw5U=eS1fE5dn0wZX3HF0oy8-oQ@mail.gmail.com Link: https://lkml.kernel.org/r/20240325134114.257544-3-david@redhat.com Signed-off-by: David Hildenbrand Cc: Lorenzo Stoakes Cc: "Mike Rapoport (IBM)" Cc: Miklos Szeredi Cc: xingwei lee Cc: yue sun Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/memfd_secret.c | 44 +++++++++++++++++++- 1 file changed, 42 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/mm/memfd_secret.c~selftests-memfd_secret-add-vmsplice-test +++ a/tools/testing/selftests/mm/memfd_secret.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "../kselftest.h" @@ -83,6 +84,43 @@ static void test_mlock_limit(int fd) pass("mlock limit is respected\n"); } +static void test_vmsplice(int fd) +{ + ssize_t transferred; + struct iovec iov; + int pipefd[2]; + char *mem; + + if (pipe(pipefd)) { + fail("pipe failed: %s\n", strerror(errno)); + return; + } + + mem = mmap(NULL, page_size, prot, mode, fd, 0); + if (mem == MAP_FAILED) { + fail("Unable to mmap secret memory\n"); + goto close_pipe; + } + + /* + * vmsplice() may use GUP-fast, which must also fail. Prefault the + * page table, so GUP-fast could find it. + */ + memset(mem, PATTERN, page_size); + + iov.iov_base = mem; + iov.iov_len = page_size; + transferred = vmsplice(pipefd[1], &iov, 1, 0); + + ksft_test_result(transferred < 0 && errno == EFAULT, + "vmsplice is blocked as expected\n"); + + munmap(mem, page_size); +close_pipe: + close(pipefd[0]); + close(pipefd[1]); +} + static void try_process_vm_read(int fd, int pipefd[2]) { struct iovec liov, riov; @@ -187,7 +225,6 @@ static void test_remote_access(int fd, c return; } - ftruncate(fd, page_size); memset(mem, PATTERN, page_size); if (write(pipefd[1], &mem, sizeof(mem)) < 0) { @@ -258,7 +295,7 @@ static void prepare(void) strerror(errno)); } -#define NUM_TESTS 4 +#define NUM_TESTS 5 int main(int argc, char *argv[]) { @@ -277,9 +314,12 @@ int main(int argc, char *argv[]) ksft_exit_fail_msg("memfd_secret failed: %s\n", strerror(errno)); } + if (ftruncate(fd, page_size)) + ksft_exit_fail_msg("ftruncate failed: %s\n", strerror(errno)); test_mlock_limit(fd); test_file_apis(fd); + test_vmsplice(fd); test_process_vm_read(fd); test_ptrace(fd); _ Patches currently in -mm which might be from david@redhat.com are mm-secretmem-fix-gup-fast-succeeding-on-secretmem-folios.patch mm-madvise-make-madv_populate_readwrite-handle-vm_fault_retry-properly.patch mm-madvise-dont-perform-madvise-vma-walk-for-madv_populate_readwrite.patch mm-userfaultfd-dont-place-zeropages-when-zeropages-are-disallowed.patch s390-mm-re-enable-the-shared-zeropage-for-pv-and-skeys-kvm-guests.patch mm-convert-folio_estimated_sharers-to-folio_likely_mapped_shared.patch selftests-memfd_secret-add-vmsplice-test.patch mm-merge-folio_is_secretmem-into-folio_fast_pin_allowed.patch