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 35A19C46467 for ; Tue, 3 Jan 2023 10:15:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8670D8E0002; Tue, 3 Jan 2023 05:15:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7F0688E0001; Tue, 3 Jan 2023 05:15:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 669158E0002; Tue, 3 Jan 2023 05:15:19 -0500 (EST) 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 50A278E0001 for ; Tue, 3 Jan 2023 05:15:19 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 07A59A0A72 for ; Tue, 3 Jan 2023 10:15:18 +0000 (UTC) X-FDA: 80313080358.19.06B96E0 Received: from mail-ed1-f42.google.com (mail-ed1-f42.google.com [209.85.208.42]) by imf05.hostedemail.com (Postfix) with ESMTP id 48D73100008 for ; Tue, 3 Jan 2023 10:15:16 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=mjSbDBWx; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none); spf=pass (imf05.hostedemail.com: domain of mingo.kernel.org@gmail.com designates 209.85.208.42 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1672740916; h=from:from:sender:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=dg4Iem/pwcu+hGrCWyFWcE0w0rA2DwqUcHLBcyuPeUc=; b=8NE3SeT3siaGrkbTCwZw0BcNSkbF7LMrVJO6R02aoO7wAE1IujXrb6UXm0AgnLYHeaRn4S MKMnhhsPrN67nQksZf7UBeXw1lakd1snNpR9MQyObFSzsKtR71Nl5BTfEgsRKLlSxsKSPW MDbCaBK76UvicSC7oNXUm3FC4KVkDys= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=mjSbDBWx; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none); spf=pass (imf05.hostedemail.com: domain of mingo.kernel.org@gmail.com designates 209.85.208.42 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1672740916; a=rsa-sha256; cv=none; b=OojVFh2A9lOFNmiW/r95C/5YZEpGPSvVk0aqFtEKeGr0YTUeEB8Hvx4h6JG5lvU4GJFLI1 HRwL0J7i8WKlfC0keCaB59DBxnpFil5n02QMOlmk01zBLIhJdKXKxWboUIqQ5XYB+LS12I vDm31kWGswqd2h6Ud34dMyleFSq66yg= Received: by mail-ed1-f42.google.com with SMTP id r26so37937339edc.5 for ; Tue, 03 Jan 2023 02:15:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=dg4Iem/pwcu+hGrCWyFWcE0w0rA2DwqUcHLBcyuPeUc=; b=mjSbDBWx33CYMdnRAunBxjnUpsQB8NQEfdMQgMgMOMnsSL2cUgoBYVoV1sYAg2p0Zp 50bdUMAQBKLBJKw+RQJGTYGVqDzPzYZoE6hNmGb1i5zXPIqLNykLk0p2pGnXFlik/t2C grRyHKq4PBadLvD2l5ItwXVsIA7HCKuk/+WfMEbq9F2aNiw017v28VGfTtFG/2AijMda veJ+wuzLKcZk3E2ifzeaHUw7UfbUh+7nT4Zs3CJDmhcZ4JEJ4e2YINxHe0YL51HMrGSZ OByncrEr9GdapTEhGBNp8zuujYcX/U+gUYtkegXnSM1hjbSRkh4T4NVSekJxNWP8fRt8 fBhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=dg4Iem/pwcu+hGrCWyFWcE0w0rA2DwqUcHLBcyuPeUc=; b=nyQbSzAbsFmgGt+9VJK69HsxPvh/sDZyyjL6LhKBa9rCODLM++Rl68SaTusw6kcd3J G75IhB8hGgTNGtTyPn/6bYBV/fn19btQKN1LWNcZK9eM3/TGs1OMYKKcRZqzvVONnSW4 6+LWpkhClE5nec050Snh0jvoumZ3L9Wbe9ZjCC+7U2EEm3MiseqmDMj3GeS9PuBQYY8F Bbah650YfMsTgYAvYKcCJrGSmOgpnFqaFp1wiAAkhiI0zGJCI4VgoWfO31WBA/O61GOQ /JwiXMxbRQ6I3gBoOUScZWh+5BaFviFTFqzGUrdB7Ab9qlTnxeDN/NiW5GrXLvike/BW oj6Q== X-Gm-Message-State: AFqh2ko9QdlEuWNQ6WfBLIpMAhm7FMNvKS46DeIFFhd4Yi/hBaEeK/Cd cPZDZA7WmttoDffNBAL6Hcg= X-Google-Smtp-Source: AMrXdXvGHahoAqytki6ZL5OVZWOTmKsQ+1eCtyz/+vLkr9dsT6hcqNhYr+klb25nfwe/d8ifvVVIMw== X-Received: by 2002:a05:6402:d5c:b0:461:68e4:15cc with SMTP id ec28-20020a0564020d5c00b0046168e415ccmr34746439edb.9.1672740914735; Tue, 03 Jan 2023 02:15:14 -0800 (PST) Received: from gmail.com (1F2EF380.nat.pool.telekom.hu. [31.46.243.128]) by smtp.gmail.com with ESMTPSA id r7-20020a170906280700b007b27aefc578sm13853448ejc.126.2023.01.03.02.15.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Jan 2023 02:15:14 -0800 (PST) Date: Tue, 3 Jan 2023 11:15:12 +0100 From: Ingo Molnar To: Vlastimil Babka Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Takashi Iwai , x86@kernel.org, "H. Peter Anvin" , patches@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Baoquan He , Dave Young , stable@vger.kernel.org Subject: Re: [PATCH] x86/kexec: fix double vfree of image->elf_headers Message-ID: References: <20230102103917.20987-1-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 48D73100008 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: o6aghwdu786bmi4cfmhm3zx1urogdxqh X-HE-Tag: 1672740916-508556 X-HE-Meta: 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 5gmXszrZ GrfF/YNzGYO/vh6p2i2lzh/FS4lHkvTlJ0BKAmNkKxzsyzcrKZH9IfSflfpWinMlgd0WLvV2mu/TlR1f9RrulTfSRVkNXE6tJKUvwEP4Ql75/P6TRn4WvpsRr+jA8eSEMFmQf37bfisU5khG52RR1InRNPngxr3fLRX/zwtWmGwiqP5Cw8ZyfeLHYyEoUd0cHfjaGiJxCs36K54+SyCMDJw4smZ5ChkawJjnU2BKpOgPXda35bJsgMm+MLFAahIVO4u+miMnacOOS3r6J4YNDZz3zBCpYx+f0D1+Xd6ItHr0003RRxo/BPLd9+bOwA05HC2vGGQOAHownI1L/l+D1QcxOky+giK8yGiZ+ 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: * Vlastimil Babka wrote: > On 1/2/23 11:39, Vlastimil Babka wrote: > > An investigation of a "Trying to vfree() nonexistent vm area" bug > > occurring in arch_kimage_file_post_load_cleanup() doing a > > vfree(image->elf_headers) in our 5.14-based kernel yielded the following > > double vfree() scenario, also present in mainline: > > > > SYSCALL_DEFINE5(kexec_file_load) > > kimage_file_alloc_init() > > kimage_file_prepare_segments() > > arch_kexec_kernel_image_probe() > > kexec_image_load_default() > > kexec_bzImage64_ops.load() > > bzImage64_load() > > crash_load_segments() > > prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz); > > image->elf_headers = kbuf.buffer; > > ret = kexec_add_buffer(&kbuf); > > if (ret) vfree((void *)image->elf_headers); // first vfree() > > if (ret) kimage_file_post_load_cleanup() > > vfree(image->elf_headers); // second vfree() > > > > AFAICS the scenario is possible since v5.19 commit b3e34a47f989 > > ("x86/kexec: fix memory leak of elf header buffer") that was marked for > > stable and also was backported to our kernel. > > > > Fix the problem by setting the pointer to NULL after the first vfree(). > > Also set elf_headers_sz to 0, as kimage_file_post_load_cleanup() does. > > > > Fixes: b3e34a47f989 ("x86/kexec: fix memory leak of elf header buffer") > > Signed-off-by: Vlastimil Babka > > Cc: Baoquan He > > Cc: Dave Young > > Cc: > > Takashi told me he sent a slightly different fix already in November: > https://lore.kernel.org/all/20221122115122.13937-1-tiwai@suse.de/ > > Seems it wasn't picked up? You might pick his then, as Baoquan acked it, and > it's removing code, not adding it. Thanks, indeed we missed that fix - Boris picked up that version in tip:x86/urgent, via: d00dd2f2645d ("x86/kexec: Fix double-free of elf header buffer") Ingo