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 DE57D81AA8 for ; Thu, 2 Apr 2026 00:46:35 +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=1775090795; cv=none; b=egIfLGBj7xNiZ1VQCpmIFivPJH8gxQKWJR4A2Liv/Bge1R3zuAdwwJo1gidzY3dFIeLCyr9ciJRF5eedAuXBtwq/WfiaoK7SKo+N5VcXdzcmcZymlXYanY0WFCMX6l6Du1ALqQ5uN8aww9gJYfY8VhuLPJb3zXO2If2gbN7A9XQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775090795; c=relaxed/simple; bh=IMcRe2G9VT4fbYVRCyLmDA7v04W5nC5Ij4Me7csOnkc=; h=Date:To:From:Subject:Message-Id; b=phYP4n6ea2jHPHpGKqcla7GgkgG8O3dZFItSHyax3C0atnKMOwg6fpDxChagKod8DUZS/Y+HnSoBGHhgV5dCDvAzoejFZGc0sj3jlkjobxtYikVqHiWKqLnLrw9LJs2blCZ72DhWdMB8UAu46tA+77VSikk73fxgyyFk0I1QXz0= 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=W24yFTip; 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="W24yFTip" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60FBFC4CEF7; Thu, 2 Apr 2026 00:46:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1775090795; bh=IMcRe2G9VT4fbYVRCyLmDA7v04W5nC5Ij4Me7csOnkc=; h=Date:To:From:Subject:From; b=W24yFTipPRVJHbpgqhVgu+BFqjkr5/sbgR/b9C1UdqSHO+a0ussh98MYhP9IpQGoh O3ECSVT9pHP3Vaqy1jWKy4WXjuo40hiBj2qllEmmaC61BQpPiGr/e4U7xKI8YwwdBL sldtro2lOwuRIeXvFcojIsKy2UcZ3pXYsqvKeGUo= Date: Wed, 01 Apr 2026 17:46:34 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,surenb@google.com,shuah@kernel.org,rppt@kernel.org,pfalcato@suse.de,mhocko@suse.com,ljs@kernel.org,liam.howlett@oracle.com,jason@zx2c4.com,jannh@google.com,david@kernel.org,anthony.yznaga@oracle.com,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-verify-droppable-mappings-cannot-be-locked.patch added to mm-new branch Message-Id: <20260402004635.60FBFC4CEF7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/mm: verify droppable mappings cannot be locked has been added to the -mm mm-new branch. Its filename is selftests-mm-verify-droppable-mappings-cannot-be-locked.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-verify-droppable-mappings-cannot-be-locked.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next 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 various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Anthony Yznaga Subject: selftests/mm: verify droppable mappings cannot be locked Date: Wed, 1 Apr 2026 17:34:17 -0700 For configs that support MAP_DROPPABLE verify that a mapping created with MAP_DROPPABLE cannot be locked via mlock(), and that it will not be locked if it's created after mlockall(MCL_FUTURE). Link: https://lkml.kernel.org/r/20260402003417.438037-3-anthony.yznaga@oracle.com Signed-off-by: Anthony Yznaga Cc: David Hildenbrand Cc: Jann Horn Cc: Jason A. Donenfeld Cc: Liam Howlett Cc: Lorenzo Stoakes (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Pedro Falcato Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/mlock2-tests.c | 91 ++++++++++++++++++-- 1 file changed, 82 insertions(+), 9 deletions(-) --- a/tools/testing/selftests/mm/mlock2-tests.c~selftests-mm-verify-droppable-mappings-cannot-be-locked +++ a/tools/testing/selftests/mm/mlock2-tests.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #define _GNU_SOURCE #include +#include #include #include #include @@ -163,14 +164,17 @@ static int lock_check(unsigned long addr return (vma_rss == vma_size); } -static int unlock_lock_check(char *map) +static int unlock_lock_check(char *map, bool mlock_supported) { - if (is_vmflag_set((unsigned long)map, LOCKED)) { + if (!is_vmflag_set((unsigned long)map, LOCKED)) + return 0; + + if (mlock_supported) ksft_print_msg("VMA flag %s is present on page 1 after unlock\n", LOCKED); - return 1; - } + else + ksft_print_msg("VMA flag %s is present on an unsupported VMA\n", LOCKED); - return 0; + return 1; } static void test_mlock_lock(void) @@ -196,7 +200,7 @@ static void test_mlock_lock(void) ksft_exit_fail_msg("munlock(): %s\n", strerror(errno)); } - ksft_test_result(!unlock_lock_check(map), "%s: Unlocked\n", __func__); + ksft_test_result(!unlock_lock_check(map, true), "%s: Unlocked\n", __func__); munmap(map, 2 * page_size); } @@ -296,7 +300,7 @@ static void test_munlockall0(void) ksft_exit_fail_msg("munlockall(): %s\n", strerror(errno)); } - ksft_test_result(!unlock_lock_check(map), "%s: No locked memory\n", __func__); + ksft_test_result(!unlock_lock_check(map, true), "%s: No locked memory\n", __func__); munmap(map, 2 * page_size); } @@ -336,7 +340,74 @@ static void test_munlockall1(void) ksft_exit_fail_msg("munlockall() %s\n", strerror(errno)); } - ksft_test_result(!unlock_lock_check(map), "%s: No locked memory\n", __func__); + ksft_test_result(!unlock_lock_check(map, true), "%s: No locked memory\n", __func__); + munmap(map, 2 * page_size); +} + +/* + * Droppable memory should not be lockable. + */ +static void test_mlock_droppable(void) +{ + char *map; + unsigned long page_size = getpagesize(); + + /* + * Ensure MCL_FUTURE is not set. + */ + if (mlockall(MCL_CURRENT)) + ksft_exit_fail_msg("mlockall(MCL_CURRENT): %s\n", strerror(errno)); + if (munlockall()) + ksft_exit_fail_msg("munlockall() %s\n", strerror(errno)); + + map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); + if (map == MAP_FAILED) { + if (errno == EOPNOTSUPP) { + ksft_test_result_skip("%s: MAP_DROPPABLE not supported\n", __func__); + return; + } + ksft_exit_fail_msg("mmap error: %s\n", strerror(errno)); + } + + if (mlock2_(map, 2 * page_size, 0)) { + munmap(map, 2 * page_size); + ksft_exit_fail_msg("mlock2(0): %s\n", strerror(errno)); + } + + ksft_test_result(!unlock_lock_check(map, false), "%s: droppable memory not locked\n", + __func__); + + munmap(map, 2 * page_size); +} + +static void test_mlockall_future_droppable(void) +{ + char *map; + unsigned long page_size = getpagesize(); + + if (mlockall(MCL_CURRENT | MCL_FUTURE)) + ksft_exit_fail_msg("mlockall(MCL_CURRENT | MCL_FUTURE): %s\n", strerror(errno)); + + map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); + + if (map == MAP_FAILED) { + if (errno == EOPNOTSUPP) { + ksft_test_result_skip("%s: MAP_DROPPABLE not supported\n", __func__); + return; + } + ksft_exit_fail_msg("mmap error: %s\n", strerror(errno)); + } + + ksft_test_result(!unlock_lock_check(map, false), "%s: droppable memory not locked\n", + __func__); + + if (munlockall()) { + munmap(map, 2 * page_size); + ksft_exit_fail_msg("munlockall() %s\n", strerror(errno)); + } + munmap(map, 2 * page_size); } @@ -442,7 +513,7 @@ int main(int argc, char **argv) munmap(map, size); - ksft_set_plan(13); + ksft_set_plan(15); test_mlock_lock(); test_mlock_onfault(); @@ -451,6 +522,8 @@ int main(int argc, char **argv) test_lock_onfault_of_present(); test_vma_management(true); test_mlockall(); + test_mlock_droppable(); + test_mlockall_future_droppable(); ksft_finished(); } _ Patches currently in -mm which might be from anthony.yznaga@oracle.com are mm-fix-mmap-errno-value-when-map_droppable-is-not-supported.patch selftests-mm-verify-droppable-mappings-cannot-be-locked.patch