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 0087D606D807 for ; Tue, 3 Nov 2026 14:48:17 +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=JiRuR+a0; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=epjMvs1d 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=8mbFNT8lVL2nvpVsUKgASJ1yFuw1L2kPoKsCbuWRO+8=; b=JiRuR+a0/CEt7XysEt6nEJF+2r LmGSzwEoPs3RPdQxrDXnqq4bpL51j/nHREGz1IBg7+5RqDRD+Do8b8/7DbTa5X9MrNi3067z17HmH zo4lascRvONIqeOXJN6CyHv5iD1Fmr7R7zP70NdY9gjrzGz1CGCwQB4BX11wV0hWYZrd0BPASkMxl KhPN/sbNCBsJ1FY9fUlMjteubIpbKSgHvz0d3Avp3utKpNeVtcKiyJfWA2gv/kSyhhfeQHd/iL4+d +SpPaEOJSYbdMaMw7kNWD/6vLLew+m7hpGkcPHgd7k1KlvKh8xL1uASrCwBHPVbgzix+RWg2tVYOw rhdzpwzQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOFo8-00000002lLH-2lkY; Tue, 03 Nov 2026 14:48:16 +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 1xOFo2-00000002lCp-24ws for kexec@lists.infradead.org; Tue, 03 Nov 2026 14:48:10 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id E99C4609E0; Tue, 3 Nov 2026 14:48:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A6791F000C1; Tue, 3 Nov 2026 14:48:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793717289; bh=8mbFNT8lVL2nvpVsUKgASJ1yFuw1L2kPoKsCbuWRO+8=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=epjMvs1dEdIwrI2DpgBsZGQorVKIJHhwUyrikWAHBc6Kk4cu+6mzN1OvGvUEUPhEM B6AUhqEbvZnjd+L44ByeppapXiuprgTdI5dgYBGzcuPQ4mliSoBdYo9ya2AhybeQeS hLysf5uAjAy1Ce1fGawoITmQs42q0WmndS/BpCcBJHCfp5/P5rgpN0KUvtsPXZ/tyI 1RZJZQTcjxHQ3TMgT1oAPoFy9LwZ7R59bQU8SwJTbZ2VhKizlrum4kIdEP7KLjnN/f n8AAaCBb12w0yRYObxfiHCa2z0CKocMdytuZrknD7LG7ju9D/FRUqPhOPy2fc6VOrS AnhnaOeX0gTFQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC 21/38] proc: let proc_remove() remove the entry it was given 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: <20261102-work-procfs-bugfixes-v1-21-59422ed3e465@kernel.org> References: <20261102-work-procfs-bugfixes-v1-0-59422ed3e465@kernel.org> <20261102-work-procfs-bugfixes-v1-21-59422ed3e465@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 03 Nov 2026 14:48:07 +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_remove() looks the entry up by its name in its parent and removes > whatever it finds there: >=20 > remove_proc_subtree(de->name, de->parent); >=20 > If the entry was removed already, say along with its parent, that is > either nothing or a different entry that got the same name in the > meantime, and de->parent may well be gone. Two removals of the same > entry are a bug in the caller, but going by the name turns it into > removing an entry that belongs to somebody else. >=20 > Since commit 895b4c0c79b0 ("fs/proc: fix uaf in proc_readdir_de()") > an entry that was unlinked has an empty rb node. So check for that > under proc_subdir_lock and otherwise remove the entry itself, with the > loop of remove_proc_subtree() moved into a helper both of them use. > Nothing can help a caller that passes an entry that has been freed > already. >=20 > Reported-by: Chris Mason > Fixes: a8ca16ea7b0a ("proc: Supply a function to remove a proc entry by P= DE") > 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/20261102-work-procf= s-bugfixes-v1-0-59422ed3e465@kernel.org?part=3D21