mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-29 23:53:32 +00:00
0fa7fa98db
Change since v1:
* Fixed inuse counters access spotted by Eric
In patch eea68e2f
(packet: Report socket mclist info via diag module) I've
introduced a "scheduling in atomic" problem in packet diag module -- the
socket list is traversed under rcu_read_lock() while performed under it sk
mclist access requires rtnl lock (i.e. -- mutex) to be taken.
[152363.820563] BUG: scheduling while atomic: crtools/12517/0x10000002
[152363.820573] 4 locks held by crtools/12517:
[152363.820581] #0: (sock_diag_mutex){+.+.+.}, at: [<ffffffff81a2dcb5>] sock_diag_rcv+0x1f/0x3e
[152363.820613] #1: (sock_diag_table_mutex){+.+.+.}, at: [<ffffffff81a2de70>] sock_diag_rcv_msg+0xdb/0x11a
[152363.820644] #2: (nlk->cb_mutex){+.+.+.}, at: [<ffffffff81a67d01>] netlink_dump+0x23/0x1ab
[152363.820693] #3: (rcu_read_lock){.+.+..}, at: [<ffffffff81b6a049>] packet_diag_dump+0x0/0x1af
Similar thing was then re-introduced by further packet diag patches (fanount
mutex and pgvec mutex for rings) :(
Apart from being terribly sorry for the above, I propose to change the packet
sk list protection from spinlock to mutex. This lock currently protects two
modifications:
* sklist
* prot inuse counters
The sklist modifications can be just reprotected with mutex since they already
occur in a sleeping context. The inuse counters modifications are trickier -- the
__this_cpu_-s are used inside, thus requiring the caller to handle the potential
issues with contexts himself. Since packet sockets' counters are modified in two
places only (packet_create and packet_release) we only need to protect the context
from being preempted. BH disabling is not required in this case.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
242 lines
5.6 KiB
C
242 lines
5.6 KiB
C
#include <linux/module.h>
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#include <linux/sock_diag.h>
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#include <linux/net.h>
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#include <linux/netdevice.h>
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#include <linux/packet_diag.h>
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#include <net/net_namespace.h>
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#include <net/sock.h>
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#include "internal.h"
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static int pdiag_put_info(const struct packet_sock *po, struct sk_buff *nlskb)
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{
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struct packet_diag_info pinfo;
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pinfo.pdi_index = po->ifindex;
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pinfo.pdi_version = po->tp_version;
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pinfo.pdi_reserve = po->tp_reserve;
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pinfo.pdi_copy_thresh = po->copy_thresh;
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pinfo.pdi_tstamp = po->tp_tstamp;
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pinfo.pdi_flags = 0;
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if (po->running)
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pinfo.pdi_flags |= PDI_RUNNING;
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if (po->auxdata)
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pinfo.pdi_flags |= PDI_AUXDATA;
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if (po->origdev)
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pinfo.pdi_flags |= PDI_ORIGDEV;
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if (po->has_vnet_hdr)
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pinfo.pdi_flags |= PDI_VNETHDR;
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if (po->tp_loss)
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pinfo.pdi_flags |= PDI_LOSS;
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return nla_put(nlskb, PACKET_DIAG_INFO, sizeof(pinfo), &pinfo);
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}
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static int pdiag_put_mclist(const struct packet_sock *po, struct sk_buff *nlskb)
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{
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struct nlattr *mca;
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struct packet_mclist *ml;
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mca = nla_nest_start(nlskb, PACKET_DIAG_MCLIST);
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if (!mca)
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return -EMSGSIZE;
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rtnl_lock();
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for (ml = po->mclist; ml; ml = ml->next) {
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struct packet_diag_mclist *dml;
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dml = nla_reserve_nohdr(nlskb, sizeof(*dml));
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if (!dml) {
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rtnl_unlock();
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nla_nest_cancel(nlskb, mca);
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return -EMSGSIZE;
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}
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dml->pdmc_index = ml->ifindex;
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dml->pdmc_type = ml->type;
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dml->pdmc_alen = ml->alen;
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dml->pdmc_count = ml->count;
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BUILD_BUG_ON(sizeof(dml->pdmc_addr) != sizeof(ml->addr));
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memcpy(dml->pdmc_addr, ml->addr, sizeof(ml->addr));
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}
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rtnl_unlock();
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nla_nest_end(nlskb, mca);
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return 0;
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}
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static int pdiag_put_ring(struct packet_ring_buffer *ring, int ver, int nl_type,
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struct sk_buff *nlskb)
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{
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struct packet_diag_ring pdr;
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if (!ring->pg_vec || ((ver > TPACKET_V2) &&
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(nl_type == PACKET_DIAG_TX_RING)))
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return 0;
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pdr.pdr_block_size = ring->pg_vec_pages << PAGE_SHIFT;
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pdr.pdr_block_nr = ring->pg_vec_len;
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pdr.pdr_frame_size = ring->frame_size;
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pdr.pdr_frame_nr = ring->frame_max + 1;
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if (ver > TPACKET_V2) {
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pdr.pdr_retire_tmo = ring->prb_bdqc.retire_blk_tov;
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pdr.pdr_sizeof_priv = ring->prb_bdqc.blk_sizeof_priv;
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pdr.pdr_features = ring->prb_bdqc.feature_req_word;
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} else {
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pdr.pdr_retire_tmo = 0;
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pdr.pdr_sizeof_priv = 0;
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pdr.pdr_features = 0;
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}
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return nla_put(nlskb, nl_type, sizeof(pdr), &pdr);
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}
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static int pdiag_put_rings_cfg(struct packet_sock *po, struct sk_buff *skb)
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{
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int ret;
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mutex_lock(&po->pg_vec_lock);
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ret = pdiag_put_ring(&po->rx_ring, po->tp_version,
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PACKET_DIAG_RX_RING, skb);
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if (!ret)
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ret = pdiag_put_ring(&po->tx_ring, po->tp_version,
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PACKET_DIAG_TX_RING, skb);
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mutex_unlock(&po->pg_vec_lock);
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return ret;
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}
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static int pdiag_put_fanout(struct packet_sock *po, struct sk_buff *nlskb)
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{
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int ret = 0;
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mutex_lock(&fanout_mutex);
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if (po->fanout) {
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u32 val;
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val = (u32)po->fanout->id | ((u32)po->fanout->type << 16);
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ret = nla_put_u32(nlskb, PACKET_DIAG_FANOUT, val);
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}
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mutex_unlock(&fanout_mutex);
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return ret;
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}
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static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct packet_diag_req *req,
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u32 pid, u32 seq, u32 flags, int sk_ino)
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{
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struct nlmsghdr *nlh;
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struct packet_diag_msg *rp;
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struct packet_sock *po = pkt_sk(sk);
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nlh = nlmsg_put(skb, pid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rp), flags);
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if (!nlh)
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return -EMSGSIZE;
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rp = nlmsg_data(nlh);
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rp->pdiag_family = AF_PACKET;
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rp->pdiag_type = sk->sk_type;
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rp->pdiag_num = ntohs(po->num);
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rp->pdiag_ino = sk_ino;
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sock_diag_save_cookie(sk, rp->pdiag_cookie);
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if ((req->pdiag_show & PACKET_SHOW_INFO) &&
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pdiag_put_info(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_MCLIST) &&
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pdiag_put_mclist(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_RING_CFG) &&
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pdiag_put_rings_cfg(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_FANOUT) &&
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pdiag_put_fanout(po, skb))
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goto out_nlmsg_trim;
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return nlmsg_end(skb, nlh);
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out_nlmsg_trim:
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nlmsg_cancel(skb, nlh);
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return -EMSGSIZE;
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}
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static int packet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
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{
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int num = 0, s_num = cb->args[0];
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struct packet_diag_req *req;
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struct net *net;
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struct sock *sk;
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struct hlist_node *node;
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net = sock_net(skb->sk);
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req = nlmsg_data(cb->nlh);
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mutex_lock(&net->packet.sklist_lock);
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sk_for_each(sk, node, &net->packet.sklist) {
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if (!net_eq(sock_net(sk), net))
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continue;
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if (num < s_num)
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goto next;
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if (sk_diag_fill(sk, skb, req, NETLINK_CB(cb->skb).pid,
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cb->nlh->nlmsg_seq, NLM_F_MULTI,
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sock_i_ino(sk)) < 0)
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goto done;
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next:
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num++;
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}
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done:
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mutex_unlock(&net->packet.sklist_lock);
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cb->args[0] = num;
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return skb->len;
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}
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static int packet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
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{
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int hdrlen = sizeof(struct packet_diag_req);
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struct net *net = sock_net(skb->sk);
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struct packet_diag_req *req;
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if (nlmsg_len(h) < hdrlen)
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return -EINVAL;
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req = nlmsg_data(h);
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/* Make it possible to support protocol filtering later */
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if (req->sdiag_protocol)
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return -EINVAL;
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if (h->nlmsg_flags & NLM_F_DUMP) {
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struct netlink_dump_control c = {
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.dump = packet_diag_dump,
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};
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return netlink_dump_start(net->diag_nlsk, skb, h, &c);
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} else
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return -EOPNOTSUPP;
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}
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static const struct sock_diag_handler packet_diag_handler = {
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.family = AF_PACKET,
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.dump = packet_diag_handler_dump,
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};
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static int __init packet_diag_init(void)
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{
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return sock_diag_register(&packet_diag_handler);
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}
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static void __exit packet_diag_exit(void)
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{
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sock_diag_unregister(&packet_diag_handler);
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}
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module_init(packet_diag_init);
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module_exit(packet_diag_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 17 /* AF_PACKET */);
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