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 609821D5CFB for ; Mon, 3 Nov 2025 00:49:43 +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=1762130983; cv=none; b=PpFzWBXNkhReBINIZf931q3Yj/WVNJhA8cz3qP663BsDqMfWy7fqvIgNXBeziS6d6bsaoy2Xdu5vHOJW+/cs0VRtP1YVQxVucyeLcQ4+umfG6AcaDym7IZX3r5lLvsohkaafkgykURqAuRRplhYtd/vn3XEsRc50JjWDRQNCSMk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762130983; c=relaxed/simple; bh=UnzcDa5GbJ/Keu/kqmoM0wzJNpUcH8PuqbDkGof7IJg=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=FLjyw9fLEIa7oAq/7HOZ2zQ0sFjz0XiGIqmwr93RvTH3k5tImm7Emj02nMbYd8MuKj/M430m4myeOTp231CbmehTaEjopD8UXS14mjE75dnnogB4X7wSAQAz+K9ul8dSaf0lWZ1tDsmSX9QmqaV2ykzU8NF/GTELNnESnDvxluI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fxV47b9t; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fxV47b9t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D32C3C4CEF7; Mon, 3 Nov 2025 00:49:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1762130983; bh=UnzcDa5GbJ/Keu/kqmoM0wzJNpUcH8PuqbDkGof7IJg=; h=Subject:To:Cc:From:Date:From; b=fxV47b9t1eBvbieC0CP9rpssJfhQWyrIK+/DhHwCXFkdTSmF0I9OmXF1d3Rkm4iep vSd7w8LdPXAjsoXsRRpxsHWXOLe1AYQWws4appuSovCMi5H10svvY1o3UgAyF25UIY +3idjp/4+lVtRxC4f2n61eaI1j6x6LSH4Zs0giQA= Subject: FAILED: patch "[PATCH] s390: Disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP" failed to apply to 6.12-stable tree To: hca@linux.ibm.com,david@redhat.com,gerald.schaefer@linux.ibm.com,luizcap@redhat.com Cc: From: Date: Mon, 03 Nov 2025 09:49:39 +0900 Message-ID: <2025110339-catching-blah-8209@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 64e2f60f355e556337fcffe80b9bcff1b22c9c42 # git commit -s git send-email --to '' --in-reply-to '2025110339-catching-blah-8209@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 64e2f60f355e556337fcffe80b9bcff1b22c9c42 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 30 Oct 2025 15:55:05 +0100 Subject: [PATCH] s390: Disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP As reported by Luiz Capitulino enabling HVO on s390 leads to reproducible crashes. The problem is that kernel page tables are modified without flushing corresponding TLB entries. Even if it looks like the empty flush_tlb_all() implementation on s390 is the problem, it is actually a different problem: on s390 it is not allowed to replace an active/valid page table entry with another valid page table entry without the detour over an invalid entry. A direct replacement may lead to random crashes and/or data corruption. In order to invalidate an entry special instructions have to be used (e.g. ipte or idte). Alternatively there are also special instructions available which allow to replace a valid entry with a different valid entry (e.g. crdte or cspg). Given that the HVO code currently does not provide the hooks to allow for an implementation which is compliant with the s390 architecture requirements, disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP again, which is basically a revert of the original patch which enabled it. Reported-by: Luiz Capitulino Closes: https://lore.kernel.org/all/20251028153930.37107-1-luizcap@redhat.com/ Fixes: 00a34d5a99c0 ("s390: select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP") Cc: stable@vger.kernel.org Tested-by: Luiz Capitulino Reviewed-by: Gerald Schaefer Reviewed-by: David Hildenbrand Signed-off-by: Heiko Carstens diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index c4145672ca34..df22b10d9141 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -158,7 +158,6 @@ config S390 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM select ARCH_WANT_KERNEL_PMD_MKWRITE select ARCH_WANT_LD_ORPHAN_WARN - select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP select ARCH_WANTS_THP_SWAP select BUILDTIME_TABLE_SORT select CLONE_BACKWARDS2