From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 824C11DED6D for ; Tue, 13 May 2025 13:17:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747142274; cv=none; b=pY6ct6AiIgXNc1qEnj9F8P7nKtSMEjAfHglydVvZuMGarpbT08z2fSRTQ6BXIdGAW/iN+PFZZ91xaXvSyMi8TvYk9rfZwfNQdk1sUM8+GgZ0SFZDa2BD/pOey1tcQ9s58kfAG0zYX7DaMwj0SVQyLxvYM+aAYj4fYCLGJKc1VbU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747142274; c=relaxed/simple; bh=+IIeoefvax3z2R5UYJE415V8jYsDaKdQT79nFLsrOxk=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=NnhI76/isT22CLEWjMUm7+ZXbeRrShqDkl2JumIahwZ9GGSl6Qu89n0rvCv5qlY0gwGt789l0uheBbNff+k0FCQ+F0RkUXbNuAF/C3WohXYkSX/LQGdvKvvWt4KHJgvKmCqPTzJA4l286oa7Bi2AwpOdmH0Vt0f2IlrpOJmwpp8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=VRoUVt53; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VRoUVt53" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1747142271; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc: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=HxxQXVVSK4rEec2wlzYJRfWIp4Ihbr4/ZHGnPtMfr/8=; b=VRoUVt531MvB2uok0u1owLwJwzNI3/fFXKzDJ4yreRfhpwSmMUKZU03fTcLfkR4GgoOMZQ lKY6prSrvJRJM2dCa3nz1+pKgaQzaFr5qENcMNUGU19Pu8nIVxg0vPJZeEKiZz/k3hydO7 XQGLO1ESjgsSn4FA6D9TnWYFwlCYa90= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-382-SkDLVpLTM2imyLFbg24TSA-1; Tue, 13 May 2025 09:17:49 -0400 X-MC-Unique: SkDLVpLTM2imyLFbg24TSA-1 X-Mimecast-MFC-AGG-ID: SkDLVpLTM2imyLFbg24TSA_1747142268 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-43cec217977so27960795e9.0 for ; Tue, 13 May 2025 06:17:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747142268; x=1747747068; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:references:cc:to:from:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=HxxQXVVSK4rEec2wlzYJRfWIp4Ihbr4/ZHGnPtMfr/8=; b=CgbPKA+1vxx8o99i1Nn10Cci3YgYOYQRKnjqU66CfKOxjrTgPGeyyPMXXZmspQNW7n iHK6+UChaabZbsQXkolYjqbIvG2WtPvcYiLvhndppo1MoVh3LQecLjjkB8nNWy4+Qo/H fTcXUFtc/zRxR3H9ZGiqoHMPE1/1pGXPHbikot9k/HDnXYLHbc/PNizFI9MzFVcj4c3a TWTrvtmR3UP3/oN49AERM+kyI44vjzzsa8luKHd1ZovWLmULP320v4hEerkzf4wNfWaS 0hA2wgPrc+ODpxrbgmHGSWwIRC2ji1NwQGY3RFIY3spRdNW+a+WeEfvrhD7iMgtD76JX QYZw== X-Gm-Message-State: AOJu0YwFToy/Z7h9j02djnvQMJcrk1TX2pSwfPEhKXCTyPQULgpD79K0 Dhh5IcPB9CcLhMJ1bIclu7MtUQ3WCRq/8XlJGvKaS5Ot1pkqmMgVDvULFqm70ngFcH6bfUnUk3E tsOpOVuspzVhcBWuiGcKzSVOsvSi1Ti8J/mpdGU/rup9sX9FW7iVQ+oDnEvxx5wmfaXenN4ME X-Gm-Gg: ASbGnctBeOZmHchpm0EBi/1LUF0K/BFyuG7llgsyvwzjSO2PUVHVBLAP8Q0mYU5gcH3 V+YPs3KszjUMoFUWJ9XL2PVHJSyR+G2tkXzFUWAaQkfz3q5zuAWPxhzyr5EByrvjwp3tLU9miK6 catYGPywcoygtd7DfzrYT6IJvA9ljfxG9Ph+28LMtjgtJAbLMNEU9C6ugTh2BjxnHZ4VIZa/a5v yE6wdUaZpYHEmo7pJTd+XFJwH27BG+mHtGLKoBS2CLCh70cuXNBpIdDVC3H4wLRbXX3XPo6jJbC NYDq0DnRD8cN88PEWPFFfu/kQXsgVh7UjJ9plL/YpyqWOq7AZ0lqs2Bes0uEZ3lDoQ4LX471tX5 yqlBIVSB3SUjfFS/EJbsioflmGxpEAqvs85iHXsc= X-Received: by 2002:a05:600c:37c8:b0:43c:ef13:7e5e with SMTP id 5b1f17b1804b1-442d6dd1de7mr130325495e9.26.1747142267991; Tue, 13 May 2025 06:17:47 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHantouXqVhTL24de5TQ1dXzQkhUda30erwWtCLKJNo5hGRQspQ1sW+fpX8kF19xdrg7cbZww== X-Received: by 2002:a05:600c:37c8:b0:43c:ef13:7e5e with SMTP id 5b1f17b1804b1-442d6dd1de7mr130325295e9.26.1747142267655; Tue, 13 May 2025 06:17:47 -0700 (PDT) Received: from ?IPV6:2003:d8:2f4d:1a00:4fdf:53e2:1a36:ba34? (p200300d82f4d1a004fdf53e21a36ba34.dip0.t-ipconnect.de. [2003:d8:2f4d:1a00:4fdf:53e2:1a36:ba34]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-442cd34bef4sm214544335e9.24.2025.05.13.06.17.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 May 2025 06:17:47 -0700 (PDT) Message-ID: <8323f942-52e1-44b4-b599-e275f1c66ede@redhat.com> Date: Tue, 13 May 2025 15:17:46 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-stable] uprobes: Revert ref_ctr_offset in uprobe_unregister error path From: David Hildenbrand To: Jiri Olsa , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Andrii Nakryiko Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org References: <20250513122125.1617722-1-jolsa@kernel.org> <60b3386e-dbb1-4fe9-bc38-d62eba4d9c50@redhat.com> Content-Language: en-US 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: <60b3386e-dbb1-4fe9-bc38-d62eba4d9c50@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 13.05.25 15:16, David Hildenbrand wrote: > On 13.05.25 14:21, Jiri Olsa wrote: >> From: Jiri Olsa >> > > Thanks for debugging. > >> There's error path that could lead to inactive uprobe: >> >> 1) uprobe_register succeeds - updates instruction to int3 and >> changes ref_ctr from 0 to 1 >> 2) uprobe_unregister fails - int3 stays in place, but ref_ctr >> is changed to 0 (it's not restored to 1 in the fail path) >> uprobe is leaked >> 3) another uprobe_register comes and re-uses the leaked uprobe >> and succeds - but int3 is already in place, so ref_ctr update >> is skipped and it stays 0 - uprobe CAN NOT be triggered now >> 4) uprobe_unregister fails because ref_ctr value is unexpected >> >> Fixing this by reverting the updated ref_ctr value back to 1 in step 2), >> which is the case when uprobe_unregister fails (int3 stays in place), >> but we have already updated refctr. >> >> The new scenario will go as follows: >> >> 1) uprobe_register succeeds - updates instruction to int3 and >> changes ref_ctr from 0 to 1 >> 2) uprobe_unregister fails - int3 stays in place and ref_ctr >> is reverted to 1.. uprobe is leaked >> 3) another uprobe_register comes and re-uses the leaked uprobe >> and succeds - but int3 is already in place, so ref_ctr update >> is skipped and it stays 1 - uprobe CAN be triggered now >> 4) uprobe_unregister succeeds >> >> Suggested-by: Oleg Nesterov > > If it's in mm-stable, we should have > > Fixes: ... > > here > >> Signed-off-by: Jiri Olsa >> --- >> Please note it's based on mm-stable branch, because it has the >> latest uprobe_write_opcode rewrite changes. >> >> kernel/events/uprobes.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c >> index 4c965ba77f9f..84ee7b590861 100644 >> --- a/kernel/events/uprobes.c >> +++ b/kernel/events/uprobes.c >> @@ -581,8 +581,8 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, >> >> out: >> /* Revert back reference counter if instruction update failed. */ >> - if (ret < 0 && is_register && ref_ctr_updated) >> - update_ref_ctr(uprobe, mm, -1); >> + if (ret < 0 && ref_ctr_updated) >> + update_ref_ctr(uprobe, mm, is_register ? -1 : 1); > > > Hm, but my patch essentially did here > > /* Revert back reference counter if instruction update failed. */ > - if (ret && is_register && ref_ctr_updated) > + if (ret < 0 && is_register && ref_ctr_updated) > update_ref_ctr(uprobe, mm, -1); > > So how come this wasn't a problem before? Oh, or was this a problem before? Then we should find the corresponding commit that needs fixing. -- Cheers, David / dhildenb