From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 89FB8606A32C for ; Thu, 5 Nov 2026 21:26:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=wo+iYWtv; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ckZU7d4Q DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=GA0+/owkDdniY30l313rN8euuBjyhEchmg5u4LglfRs=; b=wo+iYWtv/bjWqKjRcynbrPlW8T nQRMJQVhi+iLP4uYb3txRYk7KWWzNMNmPc9Av0HtZ2yuGvrI3bKo4WOaUkv8peJFmaLsS1WcU8T8t SGgMIvJ72ijHZieq2tD9yd3WV5MWLou8fG6XY4fdbX70Ey9Vx6D2p2CgBVc7caceL8jPoi9volyeR shIMUIpJ4x/f5I6zFFTZfWh4QhhhtFQV+5VRzfOVZyfBHwWOodVbVDK4th93A0HRrdPrRJHlbLUfp tZ5x7e7nzzPZaRO5wxZu6xb4n/T/hWIv7liY60S5yJHs8L5QXKplUuL9Vxujdk9ndHKtdzvUfYbW9 Cp562Rkg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xP3Cr-0000000AM4P-0Kwr; Thu, 05 Nov 2026 19:33:05 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xP3AP-0000000AKnY-2hXy for kexec@lists.infradead.org; Thu, 05 Nov 2026 19:30:40 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1B40E601DF; Thu, 5 Nov 2026 19:30:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 472581F000C1; Thu, 5 Nov 2026 19:30:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793907032; bh=GA0+/owkDdniY30l313rN8euuBjyhEchmg5u4LglfRs=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=ckZU7d4QUH1rI3q+4mXcCPdzjI6S3s0l6AJ0++PpkI/VthC4KY9jc1TUbXEy7w09a QS42jHvzTWmhpuR4sNrCVakO0luPXYf1Pep1PJq3hRlnM+G5j7LV9MiNuMbPYmYvh8 szoCOMpIPlXI4pmYgqd4WZv3emt2hKmkx/g4Acbw06/hy66OKKSy4eyXseR+7sXoS4 h0IZpdjtLDWYruhg3kAkHHame5PmfbBbyj3BLPwhrZvYj7hO9dMH7e37xj2nGdqfxY 8c7pfm36HFDGPa1muEyl/868i4Nqv0yBIOEge1rhlL08kefXVk1eQWlAc5aoAoUcje mrqw0O6Z+CNMQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RESEND v2 50/51] proc: don't pin a symlink's entry while readlink() copies it out To: "Christian Brauner" Cc: "Linus Torvalds" , "Jann Horn" , "Josef Bacik" , "Chris Mason" , "Jeff Layton" , NeilBrown , "Eric Dumazet" , "Thomas Gleixner" , "Al Viro" , "Jonathan Corbet" , "Christoph Hellwig" , "Greg Kroah-Hartman" , "Joel Granados" , "Kees Cook" , "Jan Kara" , "Jan Kara" , linux-s390@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, linux-m68k@lists.linux-m68k.org, linux-serial@vger.kernel.org, "Takashi Iwai" , linux-ext4@vger.kernel.org, "Chuck Lever" , tytso@mit.edu, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261104-work-procfs-bugfixes-v2-50-021c84d852e0@kernel.org> References: <20261104-work-procfs-bugfixes-v2-0-021c84d852e0@kernel.org> <20261104-work-procfs-bugfixes-v2-50-021c84d852e0@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 05 Nov 2026 19:30:30 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > proc_get_link() pins the entry with use_pde() and the delayed call > unpins it. vfs_readlink() copies the link to userspace in between. So a > page fault in that copy holds up remove_proc_entry() just like the > copies of reads and writes do, and the callers hold locks while they > wait. /proc/asound/ is removed with snd_card_mutex and info_mutex > held when a card changes its id. >=20 > The pin doesn't keep anything alive. proc_symlink() copies the target > and pde_free() frees it with the entry, and the inode holds a reference > to the entry. What the pin does is keep a removed symlink from being > followed. So check ->in_use instead and drop the delayed call. That > also takes an atomic pair off every traversal of /proc/net and > /proc/mounts. >=20 > Fixes: 7e0e953bb0cf ("procfs: fix race between symlink removals and trave= rsals") > Cc: stable@vger.kernel.org > Signed-off-by: Christian Brauner (Amutable) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261104-work-procf= s-bugfixes-v2-0-021c84d852e0@kernel.org?part=3D50