From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B47C070CCB; Mon, 8 Apr 2024 13:39:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712583555; cv=none; b=eXUU9VM/stX1Ikn2evGJPhJluhvpoSAelo2sx9qrwFrS35fPK6kLUJ5eMowuFZWkeRMCDPNzlNluWpBVl6FI4GgmoPPz2NKXFqad1A2Vc81nGImZPAIHSQqup5IxCGvpK549VihuFxZfSQnfW15L3mTuxJ/ScZaD6mEF/ZPkbWM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712583555; c=relaxed/simple; bh=AxqKgJh8wGFEXdiDhYYcvaXfrx2zG/K/1wTZ0+r46rw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CVl5U0Y96XzSrnnruZFlqfySl+Bvzerbagjhq3+TTkrZ0h1YXXC8YR0itHsx9ry8NCXM5ylTheUNL9qL0ok4upzKzhBlUPVAqPwPgKIaG1VwU/mg9a9H52jA9Wk165ZzfXcIoLfBB4ViDUNZaOwrzAw1Tt6g0f7nxPxW0rht88k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=R1F4QNjV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="R1F4QNjV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BAFDC43390; Mon, 8 Apr 2024 13:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712583555; bh=AxqKgJh8wGFEXdiDhYYcvaXfrx2zG/K/1wTZ0+r46rw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R1F4QNjVRozEzU+Y0AuU/gFJgJ0xrh2rSNW/PwzTRZEXTPb/spSAyGjn9B8t8UVXQ ZXnxikTGSr7a7RH5czExS/Jyacl4gahQNlJeYhHv5AizuIBfQc5RwmXuio0Ody6Cnc P0cu4BuRk8uU6X6ycbPAtBhssUuSEIh5IsbM3zQk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vladimir Benes , Jeff Layton , Chuck Lever , Sasha Levin Subject: [PATCH 6.8 191/273] nfsd: hold a lighter-weight client reference over CB_RECALL_ANY Date: Mon, 8 Apr 2024 14:57:46 +0200 Message-ID: <20240408125315.237854390@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240408125309.280181634@linuxfoundation.org> References: <20240408125309.280181634@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton [ Upstream commit 10396f4df8b75ff6ab0aa2cd74296565466f2c8d ] Currently the CB_RECALL_ANY job takes a cl_rpc_users reference to the client. While a callback job is technically an RPC that counter is really more for client-driven RPCs, and this has the effect of preventing the client from being unhashed until the callback completes. If nfsd decides to send a CB_RECALL_ANY just as the client reboots, we can end up in a situation where the callback can't complete on the (now dead) callback channel, but the new client can't connect because the old client can't be unhashed. This usually manifests as a NFS4ERR_DELAY return on the CREATE_SESSION operation. The job is only holding a reference to the client so it can clear a flag after the RPC completes. Fix this by having CB_RECALL_ANY instead hold a reference to the cl_nfsdfs.cl_ref. Typically we only take that sort of reference when dealing with the nfsdfs info files, but it should work appropriately here to ensure that the nfs4_client doesn't disappear. Fixes: 44df6f439a17 ("NFSD: add delegation reaper to react to low memory condition") Reported-by: Vladimir Benes Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/nfs4state.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 7d6c657e0409d..692ede488254a 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -2888,12 +2888,9 @@ static void nfsd4_cb_recall_any_release(struct nfsd4_callback *cb) { struct nfs4_client *clp = cb->cb_clp; - struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); - spin_lock(&nn->client_lock); clear_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags); - put_client_renew_locked(clp); - spin_unlock(&nn->client_lock); + drop_client(clp); } static const struct nfsd4_callback_ops nfsd4_cb_recall_any_ops = { @@ -6274,7 +6271,7 @@ deleg_reaper(struct nfsd_net *nn) list_add(&clp->cl_ra_cblist, &cblist); /* release in nfsd4_cb_recall_any_release */ - atomic_inc(&clp->cl_rpc_users); + kref_get(&clp->cl_nfsdfs.cl_ref); set_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags); clp->cl_ra_time = ktime_get_boottime_seconds(); } -- 2.43.0