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 70700A2D for ; Fri, 4 Jul 2025 21:23:23 +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=1751664203; cv=none; b=gz6UF2COwc9wXab9439K7eaATIychqEERB2luXQY7TJ8yqr+38ULMPYafTV873J9ygXBn2eCSDT4ogLCLfJXoAS2I2Y6xFIUpQSgml0FMGYCu0uNFLwtc5GSSTnnZYAga7pEM4EhmqtKYV3UKIHYgvLSrgYqLofkJpkYSaM0tmg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751664203; c=relaxed/simple; bh=4GqgWKHAxRVVuNcGcqZmAgeeddUlgaJVla0VTJ2EfNU=; h=Date:To:From:Subject:Message-Id; b=lpAd0JIp/oXWWhf6SFW5evoL+r7Yh/umqlAZWJl8Tq/eLDlyNGl9Ga5IvjveIr2gykcR+Jb0y/gu5mnxE5ObpeJwoWgvraEEI11GM6FKEMUFeMmbadB2KDobprAnMjGYtbexna6P+45v33rqTLfNVDRda1n8dLHG4eqPX7GPTRk= 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=jJsaCChE; 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="jJsaCChE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA715C4CEE3; Fri, 4 Jul 2025 21:23:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1751664202; bh=4GqgWKHAxRVVuNcGcqZmAgeeddUlgaJVla0VTJ2EfNU=; h=Date:To:From:Subject:From; b=jJsaCChEpuToQ8mkEdn6Avan/h0t2DFEqlMAK1jMWTuSQ6YG2AAK17gP/FnO30UqC piVH8/+hYT4bu/GW2QUBmDtQ9FnW0uW4ltwP1ucZMpbw+BnQD7eptr9gzRVFbnIQnS KV7xkONq3adxC3U1bYKkYtNc/lQI/rtuKwmaNaAM= Date: Fri, 04 Jul 2025 14:23:22 -0700 To: mm-commits@vger.kernel.org,yebin10@huawei.com,willy@infradead.org,vbabka@suse.cz,tjmercier@google.com,shuah@kernel.org,ryan.roberts@arm.com,peterx@redhat.com,paulmck@kernel.org,osalvador@suse.de,mhocko@kernel.org,lorenzo.stoakes@oracle.com,linux@weissschuh.net,liam.howlett@oracle.com,kaleshsingh@google.com,josef@toxicpanda.com,jannh@google.com,hannes@cmpxchg.org,david@redhat.com,christophe.leroy@csgroup.eu,brauner@kernel.org,andrii@kernel.org,aha310510@gmail.com,adobriyan@gmail.com,surenb@google.com,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-proc-extend-proc-pid-maps-tearing-test-to-include-vma-remapping.patch added to mm-new branch Message-Id: <20250704212322.DA715C4CEE3@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/proc: extend /proc/pid/maps tearing test to include vma remapping has been added to the -mm mm-new branch. Its filename is selftests-proc-extend-proc-pid-maps-tearing-test-to-include-vma-remapping.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-proc-extend-proc-pid-maps-tearing-test-to-include-vma-remapping.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. 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: Suren Baghdasaryan Subject: selftests/proc: extend /proc/pid/maps tearing test to include vma remapping Date: Thu, 3 Jul 2025 23:07:21 -0700 Test that /proc/pid/maps does not report unexpected holes in the address space when we concurrently remap a part of a vma into the middle of another vma. This remapping results in the destination vma being split into three parts and the part in the middle being patched back from, all done concurrently from under the reader. We should always see either original vma or the split one with no holes. Link: https://lkml.kernel.org/r/20250704060727.724817-4-surenb@google.com Signed-off-by: Suren Baghdasaryan Cc: Alexey Dobriyan Cc: Andrii Nakryiko Cc: Christian Brauner Cc: Christophe Leroy Cc: David Hildenbrand Cc: Jann Horn Cc: Jeongjun Park Cc: Johannes Weiner Cc: Josef Bacik Cc: Kalesh Singh Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Oscar Salvador Cc: "Paul E . McKenney" Cc: Peter Xu Cc: Ryan Roberts Cc: Shuah Khan Cc: Thomas Weißschuh Cc: T.J. Mercier Cc: Vlastimil Babka Cc: Ye Bin Signed-off-by: Andrew Morton --- tools/testing/selftests/proc/proc-maps-race.c | 92 ++++++++++++++++ 1 file changed, 92 insertions(+) --- a/tools/testing/selftests/proc/proc-maps-race.c~selftests-proc-extend-proc-pid-maps-tearing-test-to-include-vma-remapping +++ a/tools/testing/selftests/proc/proc-maps-race.c @@ -416,6 +416,95 @@ static void test_maps_tearing_from_resiz signal_state(mod_info, TEST_DONE); } +static inline void remap_vma(const struct vma_modifier_info *mod_info) +{ + /* + * Remap the last page of the next vma into the middle of the vma. + * This splits the current vma and the first and middle parts (the + * parts at lower addresses) become the last vma objserved in the + * first page and the first vma observed in the last page. + */ + assert(mremap(mod_info->next_addr + page_size * 2, page_size, + page_size, MREMAP_FIXED | MREMAP_MAYMOVE | MREMAP_DONTUNMAP, + mod_info->addr + page_size) != MAP_FAILED); +} + +static inline void patch_vma(const struct vma_modifier_info *mod_info) +{ + assert(!mprotect(mod_info->addr + page_size, page_size, + mod_info->prot)); +} + +static inline void check_remap_result(struct line_content *mod_last_line, + struct line_content *mod_first_line, + struct line_content *restored_last_line, + struct line_content *restored_first_line) +{ + /* Make sure vmas at the boundaries are changing */ + assert(strcmp(mod_last_line->text, restored_last_line->text) != 0); + assert(strcmp(mod_first_line->text, restored_first_line->text) != 0); +} + +static void test_maps_tearing_from_remap(int maps_fd, + struct vma_modifier_info *mod_info, + struct page_content *page1, + struct page_content *page2, + struct line_content *last_line, + struct line_content *first_line) +{ + struct line_content remapped_last_line; + struct line_content remapped_first_line; + struct line_content restored_last_line; + struct line_content restored_first_line; + + wait_for_state(mod_info, SETUP_READY); + + /* re-read the file to avoid using stale data from previous test */ + read_boundary_lines(maps_fd, page1, page2, last_line, first_line); + + mod_info->vma_modify = remap_vma; + mod_info->vma_restore = patch_vma; + mod_info->vma_mod_check = check_remap_result; + + capture_mod_pattern(maps_fd, mod_info, page1, page2, last_line, first_line, + &remapped_last_line, &remapped_first_line, + &restored_last_line, &restored_first_line); + + /* Now start concurrent modifications for test_duration_sec */ + signal_state(mod_info, TEST_READY); + + struct line_content new_last_line; + struct line_content new_first_line; + struct timespec start_ts, end_ts; + + clock_gettime(CLOCK_MONOTONIC_COARSE, &start_ts); + do { + read_boundary_lines(maps_fd, page1, page2, &new_last_line, &new_first_line); + + /* Check if we read vmas after remapping it */ + if (!strcmp(new_last_line.text, remapped_last_line.text)) { + /* + * The vmas should be consistent with remap results, + * however if the vma was concurrently restored, it + * can be reported twice (first as split one, then + * as restored one) because we found it as the next vma + * again. In that case new first line will be the same + * as the last restored line. + */ + assert(!strcmp(new_first_line.text, remapped_first_line.text) || + !strcmp(new_first_line.text, restored_last_line.text)); + } else { + /* The vmas should be consistent with the original/resored state */ + assert(!strcmp(new_last_line.text, restored_last_line.text) && + !strcmp(new_first_line.text, restored_first_line.text)); + } + clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts); + } while (end_ts.tv_sec - start_ts.tv_sec < test_duration_sec); + + /* Signal the modifyer thread to stop and wait until it exits */ + signal_state(mod_info, TEST_DONE); +} + int usage(void) { fprintf(stderr, "Userland /proc/pid/{s}maps race test cases\n"); @@ -527,6 +616,9 @@ int main(int argc, char **argv) test_maps_tearing_from_resize(maps_fd, mod_info, &page1, &page2, &last_line, &first_line); + test_maps_tearing_from_remap(maps_fd, mod_info, &page1, &page2, + &last_line, &first_line); + stop_vma_modifier(mod_info); free(page2.data); _ Patches currently in -mm which might be from surenb@google.com are selftests-proc-add-proc-pid-maps-tearing-from-vma-split-test.patch selftests-proc-extend-proc-pid-maps-tearing-test-to-include-vma-resizing.patch selftests-proc-extend-proc-pid-maps-tearing-test-to-include-vma-remapping.patch selftests-proc-test-procmap_query-ioctl-while-vma-is-concurrently-modified.patch selftests-proc-add-verbose-more-for-tests-to-facilitate-debugging.patch fs-proc-task_mmu-remove-conversion-of-seq_file-position-to-unsigned.patch fs-proc-task_mmu-read-proc-pid-maps-under-per-vma-lock.patch fs-proc-task_mmu-execute-procmap_query-ioctl-under-per-vma-locks.patch