From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 7734D21162CDC for ; Wed, 10 Oct 2018 00:45:25 -0700 (PDT) Date: Wed, 10 Oct 2018 09:45:23 +0200 From: Jan Kara Subject: Re: [PATCH] mm: Preserve _PAGE_DEVMAP across mprotect() calls Message-ID: <20181010074523.GA11507@quack2.suse.cz> References: <20181009101917.32497-1-jack@suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: linux-fsdevel , Linux MM , Jan Kara , stable , linux-nvdimm List-ID: On Tue 09-10-18 10:55:14, Dan Williams wrote: > On Tue, Oct 9, 2018 at 3:19 AM Jan Kara wrote: > > > > Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a > > result we will see warnings such as: > > > > BUG: Bad page map in process JobWrk0013 pte:800001803875ea25 pmd:7624381067 > > addr:00007f0930720000 vm_flags:280000f9 anon_vma: (null) mapping:ffff97f2384056f0 index:0 > > file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage: (null) > > CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G W 4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased) > > Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018 > > Call Trace: > > dump_stack+0x5a/0x75 > > print_bad_pte+0x217/0x2c0 > > ? enqueue_task_fair+0x76/0x9f0 > > _vm_normal_page+0xe5/0x100 > > zap_pte_range+0x148/0x740 > > unmap_page_range+0x39a/0x4b0 > > unmap_vmas+0x42/0x90 > > unmap_region+0x99/0xf0 > > ? vma_gap_callbacks_rotate+0x1a/0x20 > > do_munmap+0x255/0x3a0 > > vm_munmap+0x54/0x80 > > SyS_munmap+0x1d/0x30 > > do_syscall_64+0x74/0x150 > > entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > > ... > > > > when mprotect(2) gets used on DAX mappings. Also there is a wide variety > > of other failures that can result from the missing _PAGE_DEVMAP flag > > when the area gets used by get_user_pages() later. > > > > Fix the problem by including _PAGE_DEVMAP in a set of flags that get > > preserved by mprotect(2). > > > > Fixes: 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP") > > Fixes: ebd31197931d ("powerpc/mm: Add devmap support for ppc64") > > CC: stable@vger.kernel.org > > Signed-off-by: Jan Kara > > Looks good, do you want me to take this upstream along with the livelock fix? Yes, I think that would be best. Thanks! Honza -- Jan Kara SUSE Labs, CR _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm