From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7FB9C54E58 for ; Mon, 18 Mar 2024 09:36:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 397486B0085; Mon, 18 Mar 2024 05:36:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3462C6B0087; Mon, 18 Mar 2024 05:36:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1E6996B0088; Mon, 18 Mar 2024 05:36:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 0C6566B0085 for ; Mon, 18 Mar 2024 05:36:26 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 8D5C940DE1 for ; Mon, 18 Mar 2024 09:36:25 +0000 (UTC) X-FDA: 81909654330.19.69C4920 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf17.hostedemail.com (Postfix) with ESMTP id 38DAA40002 for ; Mon, 18 Mar 2024 09:36:23 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="QR/P6nbD"; spf=pass (imf17.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1710754583; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hrfdzjJQ+Nnuj/z3DDFPmcJG9lGAM2Y5iYa/aUBZzG4=; b=2Laq7M9cKZo55kZMcjYHR05A/CDV1JKq68YtatELFJtwzGNhGbnQbl8Eq+mSU3Iab8nTM0 w2xUB/DQEI7OFTzAXTROMzpJQTaQ+jCgINJs5u94hHzhJo3P7DmDT9coqWRvYrQVlYshn7 iPuDEAbM9gO8PBItciMJbyXztmJoSVk= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1710754583; a=rsa-sha256; cv=none; b=yaA4AE7N0Av6bWFw2ELBDUGtg+uenFj9ENQmq1Li8b3YzBfRAdlfaRim9LTfl5OHZfXdnF mwV7kXzVJHx+TNt4iwMvQXGsdsmNqQ5X6DrAYKHl8ggyvE8i7qqgu3hgEHmfoVPZPTicH2 7lorH5/AZ2MNRpagOIKS/5mPTtgKz8k= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="QR/P6nbD"; spf=pass (imf17.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710754582; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=hrfdzjJQ+Nnuj/z3DDFPmcJG9lGAM2Y5iYa/aUBZzG4=; b=QR/P6nbDKOU2KwvvDJ36kTVK3xgVh9ru03TTpD6sYtMIu6MDyyDqk7pKlctoTy+S6NJcTK 44MoZ4OGkiGdSWXXPFUhtCOrrRFERd1i6+6yTmGeQoi03usEyRLAd0jKyYHdxBKb1HAw4X Bglu69EXQ1UDKghAXZcxoVkWGol+hEA= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-52-ko4UZ-FSPV2N3A6NaLWAIw-1; Mon, 18 Mar 2024 05:36:18 -0400 X-MC-Unique: ko4UZ-FSPV2N3A6NaLWAIw-1 Received: by mail-wr1-f71.google.com with SMTP id ffacd0b85a97d-34176bb228dso258032f8f.3 for ; Mon, 18 Mar 2024 02:36:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710754577; x=1711359377; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :content-language:references:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=hrfdzjJQ+Nnuj/z3DDFPmcJG9lGAM2Y5iYa/aUBZzG4=; b=ZPxj+Jj8ycRz1jpsvftcqf9Wj7WWE3BLOe0FaE4qjfH74s3tI3hI/uL8cnDIePylbo OMCbVWtfqWY9oPCgPCJaoZ+FC9CW6X9e3T1yPhW+4CSPBLwCrq3jO+zWDf8WIKe7yqSy z0meJbfpLCS2FfbDull+kcvUa4oW9msRSB4ZkQfqOTgY0VoQXQiVXpf19PmM4/uLgJFR oPBbEWRxS7PV01QGvIjQ662vuRg1W12/GY2fCnUChSGs+ujlK3zG7MJwOmGXRUaNbQ15 Kww3IBux1rrU7OfHx8W0O+7OV0COtrlaWtU0XEuyiuMnJx80LPN69wKX0Tg4mc4CUlqC w9DQ== X-Forwarded-Encrypted: i=1; AJvYcCVAc0NamKHTDHRiussbPHaewfzZN0fSXhlI8972BpaYD6UYe/YWuQQ2kQdKNEEqk/Nf/QQ6qKgOUsrgdyLsaeGT700= X-Gm-Message-State: AOJu0YyX1Tkf/VXWgk/9fH2+h6ijqq1rlaedTqOrFmPah2LhHsVencnj D5TEnlBglCrYZ5UgpHawD8byDX6iwZMAKHoHscMEHTgX0HsMhYLSFgdlSo/gcFwJ4yjFCVGKh2Y 1yH7Tok/xLWhvFOAvZ9I3pPsrPp+NbIQCxcNT0j+R5LmZI6GM X-Received: by 2002:a05:6000:108f:b0:33e:1540:1b56 with SMTP id y15-20020a056000108f00b0033e15401b56mr8689582wrw.64.1710754577532; Mon, 18 Mar 2024 02:36:17 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFcwp2ZdXNw+6NhA9K3OfD/g/4G3n5lu8szLdKLshWscFwoaQJRBE+EgIr/GvN62MhQ70Hdfg== X-Received: by 2002:a05:6000:108f:b0:33e:1540:1b56 with SMTP id y15-20020a056000108f00b0033e15401b56mr8689557wrw.64.1710754577110; Mon, 18 Mar 2024 02:36:17 -0700 (PDT) Received: from ?IPV6:2003:cb:c737:1f00:94ff:246b:30d0:686b? (p200300cbc7371f0094ff246b30d0686b.dip0.t-ipconnect.de. [2003:cb:c737:1f00:94ff:246b:30d0:686b]) by smtp.gmail.com with ESMTPSA id f6-20020a5d50c6000000b0033e891d97d6sm9329789wrt.107.2024.03.18.02.36.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Mar 2024 02:36:16 -0700 (PDT) Message-ID: Date: Mon, 18 Mar 2024 10:36:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/ksm: fix ksm exec support for prctl To: Jinjiang Tu , akpm@linux-foundation.org, shr@devkernel.io, hannes@cmpxchg.org, riel@surriel.com, wangkefeng.wang@huawei.com, sunnanyong@huawei.com, linux-mm@kvack.org References: <20240318090441.179486-1-tujinjiang@huawei.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20240318090441.179486-1-tujinjiang@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 38DAA40002 X-Rspam-User: X-Stat-Signature: ud9m6uzw8iyr4et9wo6y446esy918r6p X-Rspamd-Server: rspam03 X-HE-Tag: 1710754583-411707 X-HE-Meta: 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 5TuRaYCV 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 18.03.24 10:04, Jinjiang Tu wrote: > commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") inherits > MMF_VM_MERGE_ANY flag when a task calls execve(). Howerver, it doesn't > create the mm_slot, so ksmd will not try to scan this task. > > To fix it, allocate and add the mm_slot to ksm_mm_head in __bprm_mm_init() > when the mm has MMF_VM_MERGE_ANY flag. That would mean that 3c6f33b7273a is effectively ineffective for fork+exec and only works with fork? > > Fixes: 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") > Signed-off-by: Jinjiang Tu > --- > fs/exec.c | 4 ++++ > include/linux/ksm.h | 13 +++++++++++++ > 2 files changed, 17 insertions(+) > > diff --git a/fs/exec.c b/fs/exec.c > index ff6f26671cfc..00f40163cc12 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -67,6 +67,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -267,6 +268,9 @@ static int __bprm_mm_init(struct linux_binprm *bprm) > goto err_free; > } > > + if (ksm_execve(mm)) > + goto err; > + > /* > * Place the stack at the largest stack address the architecture > * supports. Later, we'll move this to an appropriate place. We don't > diff --git a/include/linux/ksm.h b/include/linux/ksm.h > index 401348e9f92b..7e2b1de3996a 100644 > --- a/include/linux/ksm.h > +++ b/include/linux/ksm.h > @@ -59,6 +59,14 @@ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) > return 0; > } > > +static inline int ksm_execve(struct mm_struct *mm) > +{ > + if (test_bit(MMF_VM_MERGE_ANY, &mm->flags)) > + return __ksm_enter(mm); As soon as we did the __ksm_enter(), we have to set MMF_VM_MERGEABLE. I don't think it would be set right now, because: mm_alloc()->mm_init() will initialize the flags using mm->flags = mmf_init_flags(current->mm->flags); Whereby MMF_INIT_MASK contains only MMF_VM_MERGE_ANY_MASK. So we likely need a set_bit(MMF_VM_MERGEABLE, &mm->flags) here as well. Otherwise ksm_exit() wouldn't clean up, and we might call __ksm_enter() twice. And now I wonder, when would be the right point to call __ksm_enter(). __mmput() calls ksm_exit(). But for example, if __bprm_mm_init() fails after __ksm_enter(), we will only call mmdrop(), not cleaning up ... so that looks wrong. We would have to make sure we call __ksm_enter() only once we know that callers will call mm_put(). that is the case once we return from bprm_mm_init() with success. Maybe move the ksm_execve() to bprm_mm_init(), adding a comment that cleanup will only happen during mm_put(), so it's harder to mess up in the future? -- Cheers, David / dhildenb