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 AC2078060C; Mon, 8 Apr 2024 14:05:33 +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=1712585133; cv=none; b=rWTAXmmvK2dUrBlZng9OTJdYiQKT5/Jtl2J/+eVaY583I2V4vV6VrhxitJ9pppdtUU/96QygHQ7UclQQI0aR68XpP5beXXumkPTooVnZ00VuFx01z1NYQPr0/xcLYEVknMay3y/FQ6MRfXUX8rONlJXVAp1lWP/rHAjBjgBZeW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712585133; c=relaxed/simple; bh=jq+SpbQ8tnnq0L1d8RFpgKWrBugLUQX9XxDuwoUcuhs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Js5xTCLWiTNXxL3ZmtkX473F855vcFyCbP7l8gPRHCew8jP/18EcLMuVlmpy853X+giOozKTwBcnbsSmOsv/7rdMW4IqEPY+SgD0kUkDencT/etBNnbvK58tb31Guuh0U5DmsXiHGTC946AJNA/7Wp+le6Vlqi7P8y20wrZwl/g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=slCTdI3i; 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="slCTdI3i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36533C43390; Mon, 8 Apr 2024 14:05:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712585133; bh=jq+SpbQ8tnnq0L1d8RFpgKWrBugLUQX9XxDuwoUcuhs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=slCTdI3iTnxCud5p3nzb2KAU4i7dh0SwmVZvSs8UIcxwO01wBNMajsI6KlfUYUU42 DC5/CqbQAh3QWox8V4IHcvHm51eBGR0jvrAoQPfT5ep2627SK/FBsD2Zi3IbpaFk9e dr9WC5DufuF+TuFdwbASbVzJ3pMd5DqzXYnn8GJo= 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 5.15 674/690] nfsd: hold a lighter-weight client reference over CB_RECALL_ANY Date: Mon, 8 Apr 2024 14:59:00 +0200 Message-ID: <20240408125424.126475973@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240408125359.506372836@linuxfoundation.org> References: <20240408125359.506372836@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 5.15-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 ccc235a8bc1b4..40b5b226e504d 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -2889,12 +2889,9 @@ 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 = { @@ -6234,7 +6231,7 @@ 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