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 9397A47125C; Tue, 21 Jul 2026 18:14:38 +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=1784657679; cv=none; b=nsCrSxUAupl2w9yJPIpxw8Ok3LlDXJ9gUKHB8h+6ky3ofDPWAHuSHZ8LzFvRqHzou7/HxhJ1Ec5PLNtBI58dSNr5npURYbZk/MrVRrwPJ/AYkiHS8Ca/pCEwZc5Fc7xW6fDdLTY6KqGPTCfRCb/dRP6dQKmWQChRGKnCqexrofw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657679; c=relaxed/simple; bh=pglT3Oqajc6ZMAh0j3NcNrsH4FIcTKoiwbg2DkCN33A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nV9YKArEq+Z0cvqVKnobfmra9KsJXv68/FHfMyfO727JAuzQW+oYp5tmYodgOxGtgs2BiDE0u+8LO7nIkuYufzTzBc+p/eKJBDT7lRBColthNOA/IxLtlGtvXx+NRrRFSMMWD0xYCnQ62OFmcn2MwVjsuWROgiqAWZmzXFm8Ppg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2Xx+BIdK; 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="2Xx+BIdK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AF201F000E9; Tue, 21 Jul 2026 18:14:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657678; bh=HVjDZbqBj1nFPuU8Z2Vgci4GTA2zJ4dBN36+12WP7SI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=2Xx+BIdKRq/gjxJ9+ge6eGaFFlWvzvZkSj1sH/fjfWqLODm8xUo59qXffc9LQ8eK1 kVwN9T0YG4Zd/tDb51IUBXQJgiUurfSvRx9GdUczZtMyIKjjyru7RDHtOBiOZbYMqo Vm4pFTVJQDqc0wl8BEI/t3wQ+Qn0yx4D57791TJM= 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 6.18 0856/1611] selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap Date: Tue, 21 Jul 2026 17:16:12 +0200 Message-ID: <20260721152534.645392494@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 2bd1dac75c3f1d..cd862a619471e7 100644 --- a/tools/testing/selftests/mm/hugepage-mremap.c +++ b/tools/testing/selftests/mm/hugepage-mremap.c @@ -85,25 +85,14 @@ 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