From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 51992433BD9 for ; Mon, 6 Jul 2026 16:42:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783356163; cv=none; b=nXbVtoOEwabhzHfOvbUxE/Fn7Nxsh1hWDao+1PDmz9j0/WCGuV/WldnHjTSe3wrfEA6f5tKaGZUXPgaVSdDss8J1OxNAjV1rJEMKZl6WrjEmbwAY/47gqlLN0/uB25Stimcc6iWbdnzRp4Ain2nNIo/5K7wZav8YThUCNuGzGME= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783356163; c=relaxed/simple; bh=qtIOqaAJHMa4A53CVdpcwsWAy8/uVyBlSlv45hoArJc=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=XbSf9bW/Y5bpjzEuLO27xK5zUzW9AMfVpXLm4egAjYqEknQjwS3oiWFfvIUA7H2OGzygaOx0TLbPNh9mtcJPjBEOWAjN59J1Bl5Hjv0PlAAQeS+OxBuxim6ELgjJk3108IPHUIKhUkBwkDHLlakOEdA1RtpfAUGvCx/UPrsTJEA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mrMIBx2r; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mrMIBx2r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67CB71F000E9; Mon, 6 Jul 2026 16:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783356161; bh=NYydbcbPM/VOBT1Glw32q3dbXT8li6fMQVtHaCxsFbg=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=mrMIBx2rKjrPIMA9suY3uAH7eXYOZsRX47q/EkCdL7CcPHVyG4i8d6gaXCQ86gJ9F j0DVL/0Np3fBgGJFzEbVkIJiE6ytyTrg7wMCs7hYTAc2H/eYdCA9GQSgeawh/odxEr WJffpwrZDt4Q+n+nw4P3LzNTMkthBKBub81uXHSKqZYayRuDkpyrh1wQca7KjcxpuX Vsb/KSRNqlpYdHDUCo7g1caX8kdA0oo+iutx2QsFs5SRVWw7GSlDZoT9S0tdTLrBsE tXNl90LFPfoIUfv0lceTkQLle+lU7RnW4txDC1VaHCVWhGQ0rY4sINNbTEE66vaftg o1jfMDlvc85Hg== Message-ID: Subject: Re: [PATCH v2 0/6] NFSD: Fix UAFs in client teardown and state revocation From: Jeff Layton To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: linux-nfs@vger.kernel.org, Wolfgang Walter Date: Mon, 06 Jul 2026 12:42:40 -0400 In-Reply-To: <20260705-cel-v2-0-d88c3b68e8bc@kernel.org> References: <20260705-cel-v2-0-d88c3b68e8bc@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV 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a broader lifetime bug in > NFSD's state-revocation machinery. This series fixes the reported > crash and the sibling races found by auditing the same pattern, then > consolidates the fixes. >=20 > A stateid, and a bare lock owner reachable through the client's owner > hash, hold only a raw pointer to the owning nfs4_client; a reference > on the stateid or owner does not keep the client alive. The client > outlives its state solely because __destroy_client() drains that state > before free_client() runs. Several paths break that invariant. The > laundromat unhashes an expired delegation before revoke_delegation() > re-links it, leaving it momentarily on no client-reachable list > (patch 2). nfsd4_revoke_states() and its export and NFSv4.0 > admin-revoke siblings drop nn->client_lock and then dereference the > client again (patches 3-5). __destroy_client() walks the owner hash > and frees blocked locks with no reference held (patch 1). >=20 > --- > Changes since v1: > - Add matching UAF fixes in several other paths >=20 > --- > Chuck Lever (6): > NFSD: Prevent lock owner use-after-free during client teardown > NFSD: Prevent client use-after-free during delegation revoke > NFSD: Prevent client use-after-free during admin state revocation > NFSD: Prevent client use-after-free during export state revocation > NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cl= eanup > NFSD: Consolidate the revocation-path client unpin >=20 > fs/nfsd/netns.h | 6 ++- > fs/nfsd/nfs4state.c | 108 +++++++++++++++++++++++++++++++++++++++++++---= ------ > 2 files changed, 94 insertions(+), 20 deletions(-) > --- > base-commit: ee6ae4a6bf3565b880dfb420017337475dfbc9ea > change-id: 20260705-cel-61c1c70caa03 >=20 > Best regards, > -- =20 > Chuck Lever This all looks pretty good, aside from patch #2 which seems like it might cause an ABBA deadlock (according to Sashiko). You can add this to patches 1 and 3-5 though: Reviewed-by: Jeff Layton