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 265EC35C1A6; Tue, 21 Jul 2026 19:42:47 +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=1784662968; cv=none; b=IOcMvSYo1HxUPnc5OFwiFXFdC1Ji5b66OIs57neKbrQbCKjJoPl/Z54TqFniEeJvrDkivmTD5mcywK22BHjrR7ofUG/rd+eK9SQms6556GLXJABLv13INK+hs2PH2X4SJxoaHZqBQE4QQQ0kGOy718tLuBGIRcBY76U/5VQLr8M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784662968; c=relaxed/simple; bh=0y3g5Bfo/cj4XELgQlQq71h3mvsv+NV+BoQ9YGInKgw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AV4bhW7xLkgabiaEKwqE6GQVuy0CV4ljvEGRHl2406XyNHHxg34U3OtiCrSoKOFmQGSZZJXSzuGLUZyi2Sl+1cDx/vBihitWbssNqRuJdJBzjJNxxq0c0C+5kO6d8w7ylhqSzj2bgPUlLp1hUkmBQcw5hJNffK5a+6CtXnn7pjk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lRkuecX0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lRkuecX0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91A171F000E9; Tue, 21 Jul 2026 19:42:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784662967; bh=wQIk7eMx0eVeMnE9NZLol3TME9x4WUOs0yssy9QXmKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lRkuecX0sAdVzYkx10kuHm5iT7RA+r3OpSDgv1TWAnyT8U8fpQ5mOdi6ByW9d24Mp eA9enUahb7Ldw3g7mj3bNHVOgg5MDbQx4/J7DbdYTbbKBjQSI1kbbhIQqgZdq4gJ16 QF92oik5NhWy7osdmXFApF5Y78Sk56EFglGkstys= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sayali Patil , "David Hildenbrand (Arm)" , Venkat Rao Bagalkote , Dev Jain , Liam Howlett , Miaohe Lin , Michal Hocko , Oscar Salvador , "Ritesh Harjani (IBM)" , Shuah Khan , Zi Yan , Andrew Morton , Sasha Levin Subject: [PATCH 6.12 0602/1276] selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap Date: Tue, 21 Jul 2026 17:17:25 +0200 Message-ID: <20260721152459.584235553@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152446.065700225@linuxfoundation.org> References: <20260721152446.065700225@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sayali Patil [ Upstream commit 1df31d5ef58dc6bdf0f2a8b809152d835c60b28e ] Previously, register_region_with_uffd() created a new anonymous mapping and overwrote the address supplied by the caller before registering the range with userfaultfd. As a result, userfaultfd was applied to an unrelated anonymous mapping instead of the hugetlb region used by the test. Remove the extra mmap() and register the caller-provided address range directly using UFFDIO_REGISTER_MODE_MISSING, so that faults are generated for the hugetlb mapping used by the test. This ensures userfaultfd operates on the actual hugetlb test region and validates the expected fault handling. Before patch: running ./hugetlb-mremap ------------------------- TAP version 13 1..1 Map haddr: Returned address is 0x7eaa40000000 Map daddr: Returned address is 0x7daa40000000 Map vaddr: Returned address is 0x7faa40000000 Address returned by mmap() = 0x7fff9d000000 Mremap: Returned address is 0x7faa40000000 First hex is 0 First hex is 3020100 ok 1 Read same data Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 [PASS] ok 1 hugetlb-mremap After patch: running ./hugetb-mremap ------------------------- TAP version 13 1..1 Map haddr: Returned address is 0x7eaa40000000 Map daddr: Returned address is 0x7daa40000000 Map vaddr: Returned address is 0x7faa40000000 Registered memory at address 0x7eaa40000000 with userfaultfd Mremap: Returned address is 0x7faa40000000 First hex is 0 First hex is 3020100 ok 1 Read same data Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 [PASS] ok 1 hugetlb-mremap Link: https://lore.kernel.org/13845da872ed174316173e8996dbb5f181994017.1779296493.git.sayalip@linux.ibm.com Fixes: 12b613206474 ("mm, hugepages: add hugetlb vma mremap() test") Signed-off-by: Sayali Patil Acked-by: David Hildenbrand (Arm) Tested-by: Venkat Rao Bagalkote Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- tools/testing/selftests/mm/hugepage-mremap.c | 21 +++++--------------- 1 file changed, 5 insertions(+), 16 deletions(-) diff --git a/tools/testing/selftests/mm/hugepage-mremap.c b/tools/testing/selftests/mm/hugepage-mremap.c index c463d1c09c9b4a..72200f6dc61750 100644 --- a/tools/testing/selftests/mm/hugepage-mremap.c +++ b/tools/testing/selftests/mm/hugepage-mremap.c @@ -75,25 +75,14 @@ static void register_region_with_uffd(char *addr, size_t len) if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) ksft_exit_fail_msg("ioctl-UFFDIO_API: %s\n", strerror(errno)); - /* Create a private anonymous mapping. The memory will be - * demand-zero paged--that is, not yet allocated. When we - * actually touch the memory, it will be allocated via - * the userfaultfd. - */ - - addr = mmap(NULL, len, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if (addr == MAP_FAILED) - ksft_exit_fail_msg("mmap: %s\n", strerror(errno)); - - ksft_print_msg("Address returned by mmap() = %p\n", addr); - - /* Register the memory range of the mapping we just created for - * handling by the userfaultfd object. In mode, we request to track - * missing pages (i.e., pages that have not yet been faulted in). + /* Register the passed memory range for handling by the userfaultfd object. + * In mode, we request to track missing pages + * (i.e., pages that have not yet been faulted in). */ if (uffd_register(uffd, addr, len, true, false, false)) ksft_exit_fail_msg("ioctl-UFFDIO_REGISTER: %s\n", strerror(errno)); + + ksft_print_msg("Registered memory at address %p with userfaultfd\n", addr); } int main(int argc, char *argv[]) -- 2.53.0