From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793906998; b=GlLTFzfX8WKvZFKo9VXxlq7GNKkkD+X0e2kSDSO/Iwi236U3StaaqZ8UE9ywibZeTf9a cb09utvvTbzF9bcsIL1GMr+KdQUc0+B0D/DDvqvWoO8u2hrW6c3cVh5RrknaK++X5cFia 2r4ibqnYL3cjxVZpSRZgIQdR+Wzp9SP+TQmsGkXqpDAuGj0nCwI5/UCADE6dl6q+veFR9 wle8vjt4ALX1i8fsqZ9A7cY9+KU1HfGKqP2V1fsa4Qw2AyEkP/TaQoLWUDonHURPjNg1K L/kbzxYkjKcHXDgu8PB5Wloe/lHZOiNXYkXGq9pFwxNoYcZHyY00ITtfX2DwlKBlMXg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793906998; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=99n2ODOrbk/um2zwUpcCRu9OBem/Bf8KyNf1gWCS5EU=; b=DzfcS1D5XOtnuc79B3aBYnEOejHlHHnfxtHx0G1KMGT/X6WDaTqnM+wbkHzVvXpDNTa6 E3O2LenpVf3IVRkiJ/ERB4796dVel1+1QcnR0x3di9Sngc8X4y/XgPSSQerdIS6l7T9lX mD7DSKriqGrmqDNPkn3NK8N/uw2TD5HvLV+Y1L63cGTyywG/OZtLYRGdU/fxTLOEJEa47 mgWxNsPozVL6I0pB1SBdWzK/F6o1c8AmQGIk9WNdXha4Gc/ITKK/QeEI3hQv75f1zcRgB 1cLFLcfkUc3M788NKoGs4APwdGE9dRo/x666pp5UT9qTYlRchgAkO1i8o0cCpYA40Rg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="M/LPrtHi"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97F2660A3836; Thu, 5 Nov 2026 19:29:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=M/LPrtHi Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD6F81F00919; Thu, 5 Nov 2026 19:29:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793906998; bh=99n2ODOrbk/um2zwUpcCRu9OBem/Bf8KyNf1gWCS5EU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=M/LPrtHijTR3RtO9AShzhQ19Zy5Kl5YlzepW0MBPoQGraVjX/QE98eHLqfNiVwE2W C1UMVWmoW+TyJVni1OuvV4a4mXWG+qagXGKRLgUbC4j9LV1740dwMCB8C+TsrHbQTF 2uHmzIHBpCoO+mXz8Z9IsohhYJr1jQBdiHQKaHAIMz4YzzN8aFm39Yp482vS8dhXIB MXvy6YjsBiCNXf2trYuQ0BhqcErucVFF2clU1PSF3obpkmtHf0jhEvMnYWRJ9cS54E 2jxXTltfO1qXjaW4YvahpH63B9VKj+NIvBinZspqJjXvsxnB9IrHfzidrPZ8jB0NRQ WxxAtB2Y2uCEw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RESEND v2 34/51] proc: let proc_remove() remove the entry it was given Reply-To: sashiko-reviews@lists.linux.dev 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-v2-34-021c84d852e0@kernel.org> References: <20261104-work-procfs-bugfixes-v2-0-021c84d852e0@kernel.org> <20261104-work-procfs-bugfixes-v2-34-021c84d852e0@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 05 Nov 2026 19:29:56 +0000 X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > 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/20261104-work-procf= s-bugfixes-v2-0-021c84d852e0@kernel.org?part=3D34