From patchwork Wed Jun 4 23:11:47 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suren Baghdasaryan X-Patchwork-Id: 894104 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2BE2926B973 for ; Wed, 4 Jun 2025 23:12:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749078731; cv=none; b=j0mIdTgvJE84PeGtNo5dvLcJjx+RcW/O1qDc8J8st8DNeoAnPcJDkA3DL/jHgMPGoCKGgmJQfl+Rgrg8+dPfeqjd4bJ9HWmPCDdaanslmgjvKiWXkuBhM3iFXdJshSHq7xnoaNYJF5Pd/BiU3LxOydKR3drZV3RWBhcinQsy24g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749078731; c=relaxed/simple; bh=dk2sns38K9LKA14HdtKMJQ+uodX6+JxmbyhDMndAf5c=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=PQLC+RytDr1VzSHhs2MHncqzPhn96MCVo/JlUi/5RHxfXlcAMfUVW4A3UKWpn4quBoPx2Nk26Q3QDCNX3nknt3YJGxNbZRaLKkCTrwMHEMPKUQSp92jf/RFUrRFp3EpOmmsgelUnVvu16iFhQKIlxxM9MnYMlFbz5C5zoNriwnE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--surenb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=KyTVKZTG; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--surenb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="KyTVKZTG" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-23507382e64so2846095ad.2 for ; Wed, 04 Jun 2025 16:12:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1749078729; x=1749683529; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=0FA9HEfGx7V1U+x/ZxWl25F47mbSYtvHNegG6DkQ3X0=; b=KyTVKZTGM6FtpAntKggCjCsGe8xnCJy9WHZ4F6ycuoLqPtzicxivz2VaHigHy0iumj qudidAQSbyTL3DwyJapdllMtvsPiVZI5oKmGrFvrHbrp7AB1XG8lJoRqlo7gB8W4au5+ 5Yg3izRnpIJUnZdr5XVpzGDqDjAWEyYZ7M5YiZXxuSotktWSxubAnvfkWEk+u4e5CA+/ SSWNWf5eAByuSv2P3SinHpWIxil7v/OHARxmVja3mi3omFKxwvtlgt/MHBCGn6pPN4VB WC4zLCt4TGIP5hJ4lBPLm349pKxOUA8pAPZqciPQsi8Yl7cQ7jqTbe8OLG4cQT2Xe8Xy yqKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749078729; x=1749683529; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=0FA9HEfGx7V1U+x/ZxWl25F47mbSYtvHNegG6DkQ3X0=; b=dRA+e2Ud0x7PQltrs7CkdsZXRKHaK0lLk1+HqXFhlGaE6PDkkdrJW+K4yOzC9WNmOE XXoKkoRxOqKSac5Q57+R2gu1gVJQ9cb2CzHH7iyvXvdXdDffKKMnZGCj8ZNmV0el4Xzu 3FRxg7sJr/3Vh5k9wYIIEU66P61N5hdOIoxFImJm8K3IiNEUDHhm57RqZ9A+UTEPDzjy CDagPZwie8X9I8rncgAmj1olH3G1HAkXEA15wU9/soXnbVAubrIjOIKLFflNe0Mfs0GW RRqDvJYNRB74UI75Q6NpFUuBC6tpWa7VfF8IGlTYVuGUmWmFtm1ApuRfyXOptoIKfQYz 3vkw== X-Forwarded-Encrypted: i=1; AJvYcCUG84xh9FbC/m85ZNYUadbOCLF08JcUTGU2FhYenN6yn3tEuOY3AZMdIzIaJ4Hwt7LnOsx3TDLQVPPZgVN5shU=@vger.kernel.org X-Gm-Message-State: AOJu0YxJw0J5lvLrhmi70hJSEik2xIkDhHY1TgNZG81JNRDbeBwAfyZe HvqNYFhIBPT6eTWpPpUktri2A9bAUENwYcdewZHJPNFsZAAMjdnKzkklQen5zHkoBnsGFG5RI5T 8A2+Lhg== X-Google-Smtp-Source: AGHT+IHKTW0FyMFXnbv+r0+NsbH4HZxFH9qcykRJPxlisC0t/nE0casNv64qhrGUdh0QFtZ3/VwVrTXk6rU= X-Received: from plmt12.prod.google.com ([2002:a17:903:3d4c:b0:234:593c:eb5]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:1b45:b0:234:c5c1:9b63 with SMTP id d9443c01a7336-235e1124bcemr58010975ad.18.1749078729438; Wed, 04 Jun 2025 16:12:09 -0700 (PDT) Date: Wed, 4 Jun 2025 16:11:47 -0700 In-Reply-To: <20250604231151.799834-1-surenb@google.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250604231151.799834-1-surenb@google.com> X-Mailer: git-send-email 2.49.0.1266.g31b7d2e469-goog Message-ID: <20250604231151.799834-4-surenb@google.com> Subject: [PATCH v4 3/7] selftests/proc: extend /proc/pid/maps tearing test to include vma remapping From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, david@redhat.com, vbabka@suse.cz, peterx@redhat.com, jannh@google.com, hannes@cmpxchg.org, mhocko@kernel.org, paulmck@kernel.org, shuah@kernel.org, adobriyan@gmail.com, brauner@kernel.org, josef@toxicpanda.com, yebin10@huawei.com, linux@weissschuh.net, willy@infradead.org, osalvador@suse.de, andrii@kernel.org, ryan.roberts@arm.com, christophe.leroy@csgroup.eu, tjmercier@google.com, kaleshsingh@google.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, surenb@google.com 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. Signed-off-by: Suren Baghdasaryan --- tools/testing/selftests/proc/proc-pid-vm.c | 92 ++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/tools/testing/selftests/proc/proc-pid-vm.c b/tools/testing/selftests/proc/proc-pid-vm.c index 39842e4ec45f..1aef2db7e893 100644 --- a/tools/testing/selftests/proc/proc-pid-vm.c +++ b/tools/testing/selftests/proc/proc-pid-vm.c @@ -663,6 +663,95 @@ static void test_maps_tearing_from_resize(int maps_fd, 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); +} + static int test_maps_tearing(void) { struct vma_modifier_info *mod_info; @@ -757,6 +846,9 @@ static int test_maps_tearing(void) 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);