From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.web.de (mout.web.de [212.227.17.12]) (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 9B4D313698D; Tue, 16 Apr 2024 15:58:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.17.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713283099; cv=none; b=DhH2NdzD+y/Uryn0bwb8REObzmx+03pTe/fX3cPJKIlq3ALpC/52EFfhrNcf4whR1rHkb7JrOMQ98jsk5JHugCftX23mo8zQzleZZ1ipDF+6hwM+zyFvsJkrbgNE2uLaEfWNYmVa4V/huaEDCAtlIconPatADvelX2YPdghnwUg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713283099; c=relaxed/simple; bh=nllEtvvs6NqH5k5GLLTv3RLRUZlAuaXj2VxYKEvp3tQ=; h=Message-ID:Date:MIME-Version:To:Cc:References:Subject:From: In-Reply-To:Content-Type; b=dvHtkXYKRwMpdob7SfRgd0Bzdg2qPP7Pe+XGeGX7t4f1pPDPqGWsXgaGnMLppBwoV4WfKYRJo0A3hXcbwdlPn2QyxY4O0fb+n1zW5BouAVmY2gqxWc9UP+y+8xF6yolxEIs/Jh268DC976iwTeO4PecoBG7U2H6fuQxiLRsbaHY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=web.de; spf=pass smtp.mailfrom=web.de; dkim=pass (2048-bit key) header.d=web.de header.i=markus.elfring@web.de header.b=PqsFQpc8; arc=none smtp.client-ip=212.227.17.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=web.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=web.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=web.de header.i=markus.elfring@web.de header.b="PqsFQpc8" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=web.de; s=s29768273; t=1713283065; x=1713887865; i=markus.elfring@web.de; bh=nllEtvvs6NqH5k5GLLTv3RLRUZlAuaXj2VxYKEvp3tQ=; h=X-UI-Sender-Class:Message-ID:Date:MIME-Version:To:Cc:References: Subject:From:In-Reply-To:Content-Type:Content-Transfer-Encoding: cc:content-transfer-encoding:content-type:date:from:message-id: mime-version:reply-to:subject:to; b=PqsFQpc86gZnr20gXM0/CJH7lVBimxXIBRX8EskPX++2UUrD8+/3lDvtgYLPahLk FIF6KdHEOTrUTt9+UR0SUWv883QxV3d2STeApsWdWfG2mS0IwP+NxEUWKAzs9B+IE 9IX3JTP+5+NEYn6VTfiwX4u1uRl+0845Rixknl+wNbnfA4CTq7sC0QQWOf40q3cdt ti0qNhF9FiEiJp9r8PrmDziND6XYHrQtIf6YC1399lFHisgsAVeuejkSZvFbnk1RR gbCApXWzzotEOwg/v5c/JQiuUcTV4IOhrv6+6fw/w9aPOItUbe8Qb8gAAU49BIbCJ IaIT61ZxYTQ5g/hEmg== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from [192.168.178.21] ([94.31.85.95]) by smtp.web.de (mrweb105 [213.165.67.124]) with ESMTPSA (Nemesis) id 1MJnvf-1sCUca0uxV-00K5DT; Tue, 16 Apr 2024 17:57:45 +0200 Message-ID: Date: Tue, 16 Apr 2024 17:57:33 +0200 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Zheng Yejian , linux-trace-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Mark Rutland , Masami Hiramatsu , Mathieu Desnoyers , Steven Rostedt Cc: LKML References: <20240416112459.1444612-1-zhengyejian1@huawei.com> Subject: Re: [PATCH v2] ftrace: Fix possible use-after-free issue in ftrace_location() Content-Language: en-GB From: Markus Elfring In-Reply-To: <20240416112459.1444612-1-zhengyejian1@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:FFYeLD5kLXfbghX3LoP20kT5Jkoa52aNgyc4iVwSdKGw/0O7uyU qwv41NCR+Leot8428I/N1AGO/pXqoDpGaGutf3arxyq2WNvT//+LZxsdqEHovX0tzgxaM4t JGUclvFoGfsardn6fRzjqkh1Vj55sv0iYc1pXSEbWgqvFVd8ePKsMxbMomBQEx1ArU9vk0B Wluy8K0lUz00e6SMe4rJA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:1fbYECY+dng=;+1DYhBjlCdbR2Vf5//lqiN4Yw3R gNcEV/8sH0uXm44607oje8/jq9JLdXYw4Xe95o1zObM+k+7+0qaztqAGjgIychDdbU3x22SVo irESF06Lp4g/5+5RNK79CExkXtcXgZcUezK/62FDoRmI6d2W0J9QQRXKYta7wYbiqWZ3oSlYl FAzozpHm5bOnkhUGgZ1Un2yBujACqHbvhXSqY5UOLyF3oszp8PGdxj+F6+bx1Vr7jPzcdeNyi npHhH2KIHpfwCujIDx+uLJdAvPWLleA35IhjlydlWNBzl4UtY39BBT63gTUfV49Ir+9AgY9j9 9UgG+hI3AjoBGjc3keSsS7a8xhmxT2ZJ3yut5gI6Rr1TzeSqm/n1Sk4/weli/ujGgMokrd1kc XscO/DNqhvXHSKRyQdcwjdA0Ww/DYPZE4k9hba/0H6uPf+1VMF41XZugCHLMFq1Q4moxoDcAl HGGY+KAdh73GUDeadhB9smvRhMBpg8S5yXCEXnzu+QFMh+BJEcWQL+TFpWVL3Moz2b9pFYP+n KaMBJYrRmHcOcBW6+GT1slz0ze0vr6ThTvykO6y/welS9yT2kM2T2H3tQKGhC3qW3r28xweYl 2VQAJi/deb+TRNcURXJJ7vVbywo/tDW53wI4wN+3C90/eV9mr3GhceMNU4NY/FsnnX+ucXlqk ADGb+GVVmq5KAvcSfMzAcTgMsT6KHoBxQmlPwxYc6l3tJH6D6AXuI0Yc0EH927vWLIqFO/ubb B2ug/kiuhb3HjPxAYMyVs9WMjHk+fJ0rs9qxo0UNdeUx1/5h2WHuwLN5toOGr2GmJLuygsTr9 G0f+3yWUUE0x99PN+ETGwDaTfYddLkaVplER19FeRlQQs= =E2=80=A6 > To fix it, we hold rcu lock as lookuping ftrace record, and call > synchronize_rcu() before freeing any ftrace pages. I suggest to convert this description into an imperative wording. Regards, Markus