From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F1DD63CB54E for ; Fri, 11 Sep 2026 22:29:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789165763; cv=none; b=ZCiupuvxKtre0INfzeWOdxm6RVZD3pSSd9ixugQGKingFuZFZ2JhpuHoHpi978YDgtQpgmgkAMDWNwZ20h0TBYfiQTTTGCMLT2sPFrN7NUo1aWujvTpWx014rLXyutApmWr/G6EvCJKzxhReOXZXu02gVbl7Eb1w/wHZjr/dLSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789165763; c=relaxed/simple; bh=mqpYSyPbNLaoXnGYMJ7jbzPIk3k8jYE6uekT9X9AAhI=; h=Date:To:From:Subject:Message-Id; b=F9fizBGjMkRyMFDXCKkG6Usti9siMeAqFlZ+VQTWavN1bes4jRN4xkg7lrtpYlDWgqB3A5aSeu+unbjbPgE+1T3yZJQBtaq20YOjWVoFuOI8hmsmNl48Y056SapJJkLhE22+7Cnc3ybhh8G0kzQoBK0R82KO/U7qn/IO6Hv5nw4= 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=zYwOn3Ox; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="zYwOn3Ox" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A19C61F000FF; Fri, 11 Sep 2026 22:29:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789165761; bh=CTkpMVuY0JEBBwB+JZ1TL6crDuP00e81MU4ybZft7ZI=; h=Date:To:From:Subject; b=zYwOn3Ox5VNyobNG+HuxBjJTzFntn29xUXtJpGnxnOIFTUE1xKvOoEBaL14hKUeAZ ZiOxu/KFTUKgvN968ryYpEwUzuTTVokzdOJudfg0wWZJr5w2lspVdjn5QnU/R00kuD 3Yc6UWZiN7ja5Gkx2M8nqfkyHT3J4KfPGp6io38k= Date: Fri, 11 Sep 2026 15:29:21 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,surenb@google.com,rppt@kernel.org,mhocko@suse.com,ljs@kernel.org,liam@infradead.org,david@kernel.org,yeoreum.yun@arm.com,akpm@linux-foundation.org From: Andrew Morton Subject: + kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.patch added to mm-new branch Message-Id: <20260911222921.A19C61F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: kselftest: mm: fix potential failure for merged VMA in guard-regions has been added to the -mm mm-new branch. Its filename is kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.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: Yeoreum Yun Subject: kselftest: mm: fix potential failure for merged VMA in guard-regions Date: Fri, 11 Sep 2026 15:29:03 +0100 check_vmflag_guard() uses /proc/self/smaps to retrieve the VMA flags, but this can fail if the mapping is merged with an adjacent VMA. To avoid this potential failure, first allocate a temporary region with extra pages at both ends, unmap it, and then map the test region within the temporary address range, leaving an unmapped page on each side to prevent VMA merging. Link: https://lore.kernel.org/20260911142904.1825452-1-yeoreum.yun@arm.com Signed-off-by: Yeoreum Yun Reviewed-by: Lorenzo Stoakes (ARM) Acked-by: David Hildenbrand (Arm) Cc: Liam R. Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/guard-regions.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/mm/guard-regions.c~kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions +++ a/tools/testing/selftests/mm/guard-regions.c @@ -2257,8 +2257,18 @@ TEST_F(guard_regions, smaps) char *ptr, *ptr2; int i; - /* Map a region. */ - ptr = mmap_(self, variant, NULL, 10 * page_size, PROT_READ | PROT_WRITE, 0, 0); + /* Map then unmap placeholder to avoid adjacent merges */ + ptr = mmap_(self, variant, NULL, 12 * page_size, PROT_NONE, 0, 0); + ASSERT_NE(ptr, MAP_FAILED); + ASSERT_EQ(munmap(ptr, 12 * page_size), 0); + + /* + * Map a region for the test. Since the preceding temporary mapping + * succeeded, this mapping should also succeed without merging with + * adjacent VMAs. + */ + ptr = mmap_(self, variant, ptr + page_size, 10 * page_size, + PROT_READ | PROT_WRITE, MAP_FIXED, 0); ASSERT_NE(ptr, MAP_FAILED); /* We shouldn't yet see a guard flag. */ _ Patches currently in -mm which might be from yeoreum.yun@arm.com are kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.patch