From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (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 58BD6156F54 for ; Tue, 24 Dec 2024 07:29:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735025363; cv=none; b=dv3eLlLHvx7pUxJBGO96ssqQ8ACi/1gF/J0Zz53Akcu5BcqyFTXV7JW+UFu5kq8cOh6q5SDYWLzofkrXV94Oe+C/wjCbu+Pbac/WGsprIf0jrxUbNSk8Diy7Q5vN9NXgyQW3T/BXGysO15gpOiMqlFEvjv+z4ASOBCUfEhmHAak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735025363; c=relaxed/simple; bh=Yun9eMNkbjShPmK5XFUNA7wIo/VZNoodK6nzuvAktcU=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=groK6gP04A1gwIFf2E/btrwDIwAkFiRO7tEHzuGJyLGqCqHhrKpo0EA6OlWJKavYpowbgPE12yXSJh/zS+SyxZ/C/ioN9NojG9L7seed4CpJVf+WsaEEEciuqTT+Dcy5HU5CVNglseKGt2KzXoecblay6gSLGgPNAujAwpEwMpE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.112]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4YHRKq4xsvz21p8G; Tue, 24 Dec 2024 15:27:11 +0800 (CST) Received: from kwepemd200019.china.huawei.com (unknown [7.221.188.193]) by mail.maildlp.com (Postfix) with ESMTPS id 6A7BC1400F4; Tue, 24 Dec 2024 15:29:10 +0800 (CST) Received: from [10.173.127.72] (10.173.127.72) by kwepemd200019.china.huawei.com (7.221.188.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 24 Dec 2024 15:29:09 +0800 Subject: Re: [PATCH v2] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory To: David Hildenbrand , , Dan Williams CC: , , References: <20241219115209.574065-1-linmiaohe@huawei.com> <06a45f8a-0981-40a2-a12a-5964fcdace13@redhat.com> <1af81f0e-6500-9719-20be-505851673b58@huawei.com> <44de3a6c-6761-4ad6-a4dd-b9002a42c437@redhat.com> From: Miaohe Lin Message-ID: <1d137347-23c9-36a5-e4f0-97e572ff6097@huawei.com> Date: Tue, 24 Dec 2024 15:29:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <44de3a6c-6761-4ad6-a4dd-b9002a42c437@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemd200019.china.huawei.com (7.221.188.193) On 2024/12/23 18:42, David Hildenbrand wrote: > On 23.12.24 03:55, Miaohe Lin wrote: >> On 2024/12/20 16:50, David Hildenbrand wrote: >>> On 20.12.24 03:35, Miaohe Lin wrote: >>>> On 2024/12/19 20:18, David Hildenbrand wrote: >>>>> On 19.12.24 12:52, Miaohe Lin wrote: >>>>>> When I did memory failure tests recently, below panic occurs: >>>>>> >>>>>> page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page)) >>>>>> kernel BUG at include/linux/page-flags.h:616! >>>>>> Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI >>>>>> CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40 >>>>>> RIP: 0010:unpoison_memory+0x2f3/0x590 >>>>>> RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246 >>>>>> RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8 >>>>>> RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0 >>>>>> RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb >>>>>> R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000 >>>>>> R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe >>>>>> FS:  00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000 >>>>>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>>> CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0 >>>>>> Call Trace: >>>>>>     >>>>>>     unpoison_memory+0x2f3/0x590 >>>>>>     simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110 >>>>>>     debugfs_attr_write+0x42/0x60 >>>>>>     full_proxy_write+0x5b/0x80 >>>>>>     vfs_write+0xd5/0x540 >>>>>>     ksys_write+0x64/0xe0 >>>>>>     do_syscall_64+0xb9/0x1d0 >>>>>>     entry_SYSCALL_64_after_hwframe+0x77/0x7f >>>>>> RIP: 0033:0x7f08f0314887 >>>>>> RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 >>>>>> RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887 >>>>>> RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001 >>>>>> RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff >>>>>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 >>>>>> R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00 >>>>>>     >>>>>> Modules linked in: hwpoison_inject >>>>>> ---[ end trace 0000000000000000 ]--- >>>>>> RIP: 0010:unpoison_memory+0x2f3/0x590 >>>>>> RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246 >>>>>> RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8 >>>>>> RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0 >>>>>> RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb >>>>>> R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000 >>>>>> R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe >>>>>> FS:  00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000 >>>>>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>>> CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0 >>>>>> Kernel panic - not syncing: Fatal exception >>>>>> Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) >>>>>> ---[ end Kernel panic - not syncing: Fatal exception ]--- >>>>>> >>>>>> The root cause is that unpoison_memory() tries to check the PG_HWPoison >>>>>> flags of an uninitialized page. So VM_BUG_ON_PAGE(PagePoisoned(page)) is >>>>>> triggered. This can be reproduced by below steps: >>>>>> 1.Offline memory block: >>>>>>     echo offline > /sys/devices/system/memory/memory12/state >>>>>> 2.Get offlined memory pfn: >>>>>>     page-types -b n -rlN >>>>>> 3.Write pfn to unpoison-pfn >>>>>>     echo > /sys/kernel/debug/hwpoison/unpoison-pfn >>>>>> >>>>>> Signed-off-by: Miaohe Lin >>>>>> --- >>>>>> v2: Use pfn_to_online_page per David. Thanks. >>>>>> --- >>>>>>     mm/memory-failure.c | 14 +++++++++++--- >>>>>>     1 file changed, 11 insertions(+), 3 deletions(-) >>>>>> >>>>>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >>>>>> index a7b8ccd29b6f..02be0596ce67 100644 >>>>>> --- a/mm/memory-failure.c >>>>>> +++ b/mm/memory-failure.c >>>>>> @@ -2556,10 +2556,18 @@ int unpoison_memory(unsigned long pfn) >>>>>>         static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, >>>>>>                         DEFAULT_RATELIMIT_BURST); >>>>>>     -    if (!pfn_valid(pfn)) >>>>>> -        return -ENXIO; >>>>>> +    p = pfn_to_online_page(pfn); >>>>>> +    if (!p) { >>>>>> +        struct dev_pagemap *pgmap; >>>>>>     -    p = pfn_to_page(pfn); >>>>>> +        if (!pfn_valid(pfn)) >>>>>> +            return -ENXIO; >>>>>> +        pgmap = get_dev_pagemap(pfn, NULL); >>>>>> +        if (!pgmap) >>>>>> +            return -ENXIO; >>>>>> +        put_dev_pagemap(pgmap); >>>>>> +        p = pfn_to_page(pfn); >>>>>> +    } >>>>> >>>>> Hm, I wonder if we can do anything reasonable with ZONE_DEVICE pages here? >>>> >>>> All I can see in unpoison_memory() is folio_test_clear_hwpoison() for ZONE_DEVICE pages. >>> >>> IIRC, it can only be triggered via debugfs in special kernel configs. So chances are this was never ever actually run against a ZONE_DEVICE page. >> >> If ZONE_DEVICE pages are never expected, we can simply filter them out. > > Looking into some details, I think we should just ignore ZONE_DEVICE for now, I'm pretty sure that it's not handled correctly. > > So I suggest to fail if pfn_to_online_page() == NULL, just like soft_offline_page() would. I think current code doesn't take ZONE_DEVICE pages into account. So I tend to ignore them too. But let's wait some time for input from Dan. Thanks. .