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 9237BA31 for ; Tue, 12 Sep 2023 15:13:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 303E5C433C8; Tue, 12 Sep 2023 15:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694531626; bh=2L5Bh1G8YCmECxIJnsFzVig/S0IZ4CVAWBpDmSDebTs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dbRVB3AlRvUVWAQA6Dj1F2x7Rl9KDZaVcxb/+z8e2+/eSJegJltepUof0VPErIT2b tAAb3FOebHzyzMsb2l5hIqHaz4r5xTDtXzLos3H7hPahs3Ta2IBXoMPeE1tLNtkURd vZ664z3ZnZtRCTtdTLiLXCyD/0VaivqxnNNwi+w+0DW6k2+/OlR3XzEDUxFWvgPMkz FPfgtXqcfQIuCcrFFeHWRS4+E8e+0EuMVWPE7610CW9CYpkJwtEJVCa7WJgDPp58o6 hnITEQHCd65yfe6NVy7+0tTjDLI5QYuawgv8i2eGdHR9XNBZ0dLoSH49VWjtXJmzku 3MssGYna6kkjA== Date: Tue, 12 Sep 2023 17:13:40 +0200 From: Simon Horman To: Lorenzo Bianconi Cc: linux-nfs@vger.kernel.org, lorenzo.bianconi@redhat.com, chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de, netdev@vger.kernel.org Subject: Re: [PATCH v8 3/3] NFSD: add rpc_status netlink support Message-ID: <20230912151340.GH401982@kernel.org> References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Sep 11, 2023 at 02:49:46PM +0200, Lorenzo Bianconi wrote: > Introduce rpc_status netlink support for NFSD in order to dump pending > RPC requests debugging information from userspace. > > Tested-by: Jeff Layton > Signed-off-by: Lorenzo Bianconi o Hi Lorenzo, some minor feedback from my side. ... > int nfsd_server_nl_rpc_status_get_dumpit(struct sk_buff *skb, > struct netlink_callback *cb) > { > + struct nfsd_net *nn = net_generic(sock_net(skb->sk), nfsd_net_id); > + int i, ret, rqstp_index; > + > + rcu_read_lock(); > + > + for (i = 0; i < nn->nfsd_serv->sv_nrpools; i++) { > + struct svc_rqst *rqstp; > + > + if (i < cb->args[0]) /* already consumed */ > + continue; > + > + rqstp_index = 0; > + list_for_each_entry_rcu(rqstp, > + &nn->nfsd_serv->sv_pools[i].sp_all_threads, > + rq_all) { > + struct nfsd_genl_rqstp genl_rqstp; > + unsigned int status_counter; > + > + if (rqstp_index++ < cb->args[1]) /* already consumed */ > + continue; > + /* > + * Acquire rq_status_counter before parsing the rqst > + * fields. rq_status_counter is set to an odd value in > + * order to notify the consumers the rqstp fields are > + * meaningful. > + */ > + status_counter = > + smp_load_acquire(&rqstp->rq_status_counter); > + if (!(status_counter & 1)) > + continue; > + > + genl_rqstp.rq_xid = rqstp->rq_xid; > + genl_rqstp.rq_flags = rqstp->rq_flags; > + genl_rqstp.rq_vers = rqstp->rq_vers; > + genl_rqstp.rq_prog = rqstp->rq_prog; > + genl_rqstp.rq_proc = rqstp->rq_proc; > + genl_rqstp.rq_stime = rqstp->rq_stime; > + genl_rqstp.opcnt = 0; > + memcpy(&genl_rqstp.daddr, svc_daddr(rqstp), > + sizeof(struct sockaddr)); > + memcpy(&genl_rqstp.saddr, svc_addr(rqstp), > + sizeof(struct sockaddr)); > + > +#ifdef CONFIG_NFSD_V4 > + if (rqstp->rq_vers == NFS4_VERSION && > + rqstp->rq_proc == NFSPROC4_COMPOUND) { > + /* NFSv4 compund */ nit: compound > + struct nfsd4_compoundargs *args; > + int j; > + > + args = rqstp->rq_argp; > + genl_rqstp.opcnt = args->opcnt; > + for (j = 0; j < genl_rqstp.opcnt; j++) > + genl_rqstp.opnum[j] = > + args->ops[j].opnum; > + } > +#endif /* CONFIG_NFSD_V4 */ > + > + /* > + * Acquire rq_status_counter before reporting the rqst > + * fields to the user. > + */ > + if (smp_load_acquire(&rqstp->rq_status_counter) != > + status_counter) > + continue; > + > + ret = nfsd_genl_rpc_status_compose_msg(skb, cb, > + &genl_rqstp); > + if (ret) > + goto out; > + } > + } > + > + cb->args[0] = i; > + cb->args[1] = rqstp_index; I'm unsure if this is possible, but if the for loop above iterates zero times, or for all iterations (i < cb->args[0]), then rqstp_index will be used uninitialised here. Flagged by Smatch. > + ret = skb->len; > +out: > + rcu_read_unlock(); > + > + return ret; > +} ... > diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h > index 11c14faa6c67..d787bd38c053 100644 > --- a/fs/nfsd/nfsd.h > +++ b/fs/nfsd/nfsd.h > @@ -62,6 +62,22 @@ struct readdir_cd { > __be32 err; /* 0, nfserr, or nfserr_eof */ > }; > > +/* Maximum number of operations per session compound */ > +#define NFSD_MAX_OPS_PER_COMPOUND 50 > + > +struct nfsd_genl_rqstp { > + struct sockaddr daddr; > + struct sockaddr saddr; > + unsigned long rq_flags; > + ktime_t rq_stime; > + __be32 rq_xid; > + u32 rq_vers; > + u32 rq_prog; > + u32 rq_proc; > + /* NFSv4 compund */ nit: compound > + u32 opnum[NFSD_MAX_OPS_PER_COMPOUND]; > + u16 opcnt; > +}; > > extern struct svc_program nfsd_program; > extern const struct svc_version nfsd_version2, nfsd_version3, nfsd_version4; ...