From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) (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 8258F4A08 for ; Fri, 20 Dec 2024 02:35:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734662154; cv=none; b=k03K8fGqdLxFznhlMgO5L9zBv/qcHYT7x48rrWqC488PEezMGxzimkrKzvD42pNU4mAb0s5AC1NAqvwnw3cMQeNw4gaP/aHiHzJ2UkDg3zYEImgXhW2UvE39r9wmM4EnSau3MMyFXPJkt9dGibNjDdDF1kcZMfC60iULEY71kPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734662154; c=relaxed/simple; bh=DkoXe9CzwbZ7lcYcRamCugqpL33UqOYHHAI8F5zVc2U=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=uefgWllFVfPl73uLPl6OmwF43jxWkw8q9w3ltbHlqmihRWyHQL7sGataGUtEx6oFIRO9W/hbST7VQOHor0owflTjput+rnKyle1offbXqE6x2dW7yivGkEVTkrxv6kanO97mghpSxcEeERqaY4d7h1EYMyzqHVXl+R6gmQ16yoU= 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=45.249.212.189 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 [172.19.163.174]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4YDs1G46LpzRjvS; Fri, 20 Dec 2024 10:33:54 +0800 (CST) Received: from kwepemd200019.china.huawei.com (unknown [7.221.188.193]) by mail.maildlp.com (Postfix) with ESMTPS id 01ABC1400DD; Fri, 20 Dec 2024 10:35:49 +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; Fri, 20 Dec 2024 10:35:48 +0800 Subject: Re: [PATCH v2] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory To: David Hildenbrand , CC: , , , Dan Williams References: <20241219115209.574065-1-linmiaohe@huawei.com> <06a45f8a-0981-40a2-a12a-5964fcdace13@redhat.com> From: Miaohe Lin Message-ID: Date: Fri, 20 Dec 2024 10:35:47 +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: <06a45f8a-0981-40a2-a12a-5964fcdace13@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 2024/12/19 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. > > CCing Dan, maybe he knows if this interface used to do something reasonable with ZONE_DEVICE pages. > > Also, I'm not sure about using the page after doing the put_dev_pagemap(). Likely we would have to do that at the before exiting from this function. IMHO, the page can be used after doing put_dev_pagemap(). The page should still be available while it has HWPoison set. Or are you worrying about memory offline? That might not be the scope of this problem. But I might be miss something. Thanks. .