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 48FAA27EFFA; Tue, 28 Oct 2025 21:53:36 +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=1761688416; cv=none; b=D4RFoLPqPPd2cpwR2iWd+p87dB0IIwIxIxBELpqcxsAz+OhDR83OIbHxM49jU3iFOu45v6AH7O483I/9ZZUKXVofK2hUGFPEynMsd22lAumLBfq/G6udHDR1lvzUKGmxPS/k+nln/961XzBH0dZEtVWmjRhuCmK+38rAXLFTGqk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761688416; c=relaxed/simple; bh=JPCaK8/B5tsYDz94pQe8nGhHm3auqtQ3gChlHg2P/bM=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=cUyCYSeKqRE+sg8mjvnsRHeCwD7ke+n1d3pmZLFKAdBucggnZfEalxdhOTk628bqCMg3uhMb+YkFRNJx0+8WmQ2NVOvWhlI+XbWjhomAct9vy+C8b2KF8ZjpOUlJR53/niihRnM3nFOKOGHdLNkJqubo3gOyXVjDGUPixH4TV04= 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=jUDfUc7m; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="jUDfUc7m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86EE0C4CEE7; Tue, 28 Oct 2025 21:53:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1761688416; bh=JPCaK8/B5tsYDz94pQe8nGhHm3auqtQ3gChlHg2P/bM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=jUDfUc7mEFZUX45qomM6RsYqoM/5CDi75b7/yyE4Z73kJovnvDmd/C8y4u1uj24dF ipBJjGLGPtR53JWmGj6U0tOIvgXHUDnwdse8EQsjVQofHFVhizI4f1CQnepNrgthao 2O7U1frt90PzjaFvpfA68R420ut+CTY5fKNVrsy8= Date: Tue, 28 Oct 2025 14:53:34 -0700 From: Andrew Morton To: Luiz Capitulino Cc: hca@linux.ibm.com, borntraeger@linux.ibm.com, joao.m.martins@oracle.com, mike.kravetz@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, gor@linux.ibm.com, gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com, osalvador@suse.de, david@redhat.com, aneesh.kumar@kernel.org Subject: Re: [PATCH v2] s390: fix HugeTLB vmemmap optimization crash Message-Id: <20251028145334.5a97211e0e46ca42fe2fa0d0@linux-foundation.org> In-Reply-To: <20251028211533.47694-1-luizcap@redhat.com> References: <20251028211533.47694-1-luizcap@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 28 Oct 2025 17:15:33 -0400 Luiz Capitulino wrote: > A reproducible crash occurs when enabling HugeTLB vmemmap optimization (HVO) > on s390. The crash and the proposed fix were worked on an s390 KVM guest > running on an older hypervisor, as I don't have access to an LPAR. However, > the same issue should occur on bare-metal. > > Reproducer (it may take a few runs to trigger): > > # sysctl vm.hugetlb_optimize_vmemmap=1 > # echo 1 > /proc/sys/vm/nr_hugepages > # echo 0 > /proc/sys/vm/nr_hugepages > > ... > > This commit fixes this by implementing flush_tlb_all() on s390 as an > alias to __tlb_flush_global(). This should cause a flush on all TLB > entries on all CPUs as expected by the flush_tlb_all() semantics. > > ... > > arch/s390/include/asm/tlbflush.h | 6 +++++- Thanks, I'll add this to mm.git. If s390 people prefer to merge it (or nack it!) then please do so and I'll drop the mm.git copy.