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inet: ipmr: fix data-races
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Following fields of 'struct mr_mfc' can be updated
concurrently (no lock protection) from ip_mr_forward()
and ip6_mr_forward()

- bytes
- pkt
- wrong_if
- lastuse

They also can be read from other functions.

Convert bytes, pkt and wrong_if to atomic_long_t,
and use READ_ONCE()/WRITE_ONCE() for lastuse.

Fixes: 1da177e ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250114221049.1190631-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Eric Dumazet authored and Jakub Kicinski committed Jan 15, 2025
1 parent bf38a2f commit 3440fa3
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Showing 5 changed files with 38 additions and 38 deletions.
8 changes: 4 additions & 4 deletions drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1003,10 +1003,10 @@ static void mlxsw_sp_mr_route_stats_update(struct mlxsw_sp *mlxsw_sp,
mr->mr_ops->route_stats(mlxsw_sp, mr_route->route_priv, &packets,
&bytes);

if (mr_route->mfc->mfc_un.res.pkt != packets)
mr_route->mfc->mfc_un.res.lastuse = jiffies;
mr_route->mfc->mfc_un.res.pkt = packets;
mr_route->mfc->mfc_un.res.bytes = bytes;
if (atomic_long_read(&mr_route->mfc->mfc_un.res.pkt) != packets)
WRITE_ONCE(mr_route->mfc->mfc_un.res.lastuse, jiffies);
atomic_long_set(&mr_route->mfc->mfc_un.res.pkt, packets);
atomic_long_set(&mr_route->mfc->mfc_un.res.bytes, bytes);
}

static void mlxsw_sp_mr_stats_update(struct work_struct *work)
Expand Down
6 changes: 3 additions & 3 deletions include/linux/mroute_base.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,9 +146,9 @@ struct mr_mfc {
unsigned long last_assert;
int minvif;
int maxvif;
unsigned long bytes;
unsigned long pkt;
unsigned long wrong_if;
atomic_long_t bytes;
atomic_long_t pkt;
atomic_long_t wrong_if;
unsigned long lastuse;
unsigned char ttls[MAXVIFS];
refcount_t refcount;
Expand Down
28 changes: 14 additions & 14 deletions net/ipv4/ipmr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -831,7 +831,7 @@ static void ipmr_update_thresholds(struct mr_table *mrt, struct mr_mfc *cache,
cache->mfc_un.res.maxvif = vifi + 1;
}
}
cache->mfc_un.res.lastuse = jiffies;
WRITE_ONCE(cache->mfc_un.res.lastuse, jiffies);
}

static int vif_add(struct net *net, struct mr_table *mrt,
Expand Down Expand Up @@ -1681,9 +1681,9 @@ int ipmr_ioctl(struct sock *sk, int cmd, void *arg)
rcu_read_lock();
c = ipmr_cache_find(mrt, sr->src.s_addr, sr->grp.s_addr);
if (c) {
sr->pktcnt = c->_c.mfc_un.res.pkt;
sr->bytecnt = c->_c.mfc_un.res.bytes;
sr->wrong_if = c->_c.mfc_un.res.wrong_if;
sr->pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
sr->bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
sr->wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
rcu_read_unlock();
return 0;
}
Expand Down Expand Up @@ -1753,9 +1753,9 @@ int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
rcu_read_lock();
c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);
if (c) {
sr.pktcnt = c->_c.mfc_un.res.pkt;
sr.bytecnt = c->_c.mfc_un.res.bytes;
sr.wrong_if = c->_c.mfc_un.res.wrong_if;
sr.pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
sr.bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
sr.wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
rcu_read_unlock();

if (copy_to_user(arg, &sr, sizeof(sr)))
Expand Down Expand Up @@ -1988,9 +1988,9 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
int vif, ct;

vif = c->_c.mfc_parent;
c->_c.mfc_un.res.pkt++;
c->_c.mfc_un.res.bytes += skb->len;
c->_c.mfc_un.res.lastuse = jiffies;
atomic_long_inc(&c->_c.mfc_un.res.pkt);
atomic_long_add(skb->len, &c->_c.mfc_un.res.bytes);
WRITE_ONCE(c->_c.mfc_un.res.lastuse, jiffies);

if (c->mfc_origin == htonl(INADDR_ANY) && true_vifi >= 0) {
struct mfc_cache *cache_proxy;
Expand Down Expand Up @@ -2021,7 +2021,7 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
goto dont_forward;
}

c->_c.mfc_un.res.wrong_if++;
atomic_long_inc(&c->_c.mfc_un.res.wrong_if);

if (true_vifi >= 0 && mrt->mroute_do_assert &&
/* pimsm uses asserts, when switching from RPT to SPT,
Expand Down Expand Up @@ -3029,9 +3029,9 @@ static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)

if (it->cache != &mrt->mfc_unres_queue) {
seq_printf(seq, " %8lu %8lu %8lu",
mfc->_c.mfc_un.res.pkt,
mfc->_c.mfc_un.res.bytes,
mfc->_c.mfc_un.res.wrong_if);
atomic_long_read(&mfc->_c.mfc_un.res.pkt),
atomic_long_read(&mfc->_c.mfc_un.res.bytes),
atomic_long_read(&mfc->_c.mfc_un.res.wrong_if));
for (n = mfc->_c.mfc_un.res.minvif;
n < mfc->_c.mfc_un.res.maxvif; n++) {
if (VIF_EXISTS(mrt, n) &&
Expand Down
6 changes: 3 additions & 3 deletions net/ipv4/ipmr_base.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -263,9 +263,9 @@ int mr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
lastuse = READ_ONCE(c->mfc_un.res.lastuse);
lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;

mfcs.mfcs_packets = c->mfc_un.res.pkt;
mfcs.mfcs_bytes = c->mfc_un.res.bytes;
mfcs.mfcs_wrong_if = c->mfc_un.res.wrong_if;
mfcs.mfcs_packets = atomic_long_read(&c->mfc_un.res.pkt);
mfcs.mfcs_bytes = atomic_long_read(&c->mfc_un.res.bytes);
mfcs.mfcs_wrong_if = atomic_long_read(&c->mfc_un.res.wrong_if);
if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
RTA_PAD))
Expand Down
28 changes: 14 additions & 14 deletions net/ipv6/ip6mr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -520,9 +520,9 @@ static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)

if (it->cache != &mrt->mfc_unres_queue) {
seq_printf(seq, " %8lu %8lu %8lu",
mfc->_c.mfc_un.res.pkt,
mfc->_c.mfc_un.res.bytes,
mfc->_c.mfc_un.res.wrong_if);
atomic_long_read(&mfc->_c.mfc_un.res.pkt),
atomic_long_read(&mfc->_c.mfc_un.res.bytes),
atomic_long_read(&mfc->_c.mfc_un.res.wrong_if));
for (n = mfc->_c.mfc_un.res.minvif;
n < mfc->_c.mfc_un.res.maxvif; n++) {
if (VIF_EXISTS(mrt, n) &&
Expand Down Expand Up @@ -884,7 +884,7 @@ static void ip6mr_update_thresholds(struct mr_table *mrt,
cache->mfc_un.res.maxvif = vifi + 1;
}
}
cache->mfc_un.res.lastuse = jiffies;
WRITE_ONCE(cache->mfc_un.res.lastuse, jiffies);
}

static int mif6_add(struct net *net, struct mr_table *mrt,
Expand Down Expand Up @@ -1945,9 +1945,9 @@ int ip6mr_ioctl(struct sock *sk, int cmd, void *arg)
c = ip6mr_cache_find(mrt, &sr->src.sin6_addr,
&sr->grp.sin6_addr);
if (c) {
sr->pktcnt = c->_c.mfc_un.res.pkt;
sr->bytecnt = c->_c.mfc_un.res.bytes;
sr->wrong_if = c->_c.mfc_un.res.wrong_if;
sr->pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
sr->bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
sr->wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
rcu_read_unlock();
return 0;
}
Expand Down Expand Up @@ -2017,9 +2017,9 @@ int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
rcu_read_lock();
c = ip6mr_cache_find(mrt, &sr.src.sin6_addr, &sr.grp.sin6_addr);
if (c) {
sr.pktcnt = c->_c.mfc_un.res.pkt;
sr.bytecnt = c->_c.mfc_un.res.bytes;
sr.wrong_if = c->_c.mfc_un.res.wrong_if;
sr.pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
sr.bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
sr.wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
rcu_read_unlock();

if (copy_to_user(arg, &sr, sizeof(sr)))
Expand Down Expand Up @@ -2142,9 +2142,9 @@ static void ip6_mr_forward(struct net *net, struct mr_table *mrt,
int true_vifi = ip6mr_find_vif(mrt, dev);

vif = c->_c.mfc_parent;
c->_c.mfc_un.res.pkt++;
c->_c.mfc_un.res.bytes += skb->len;
c->_c.mfc_un.res.lastuse = jiffies;
atomic_long_inc(&c->_c.mfc_un.res.pkt);
atomic_long_add(skb->len, &c->_c.mfc_un.res.bytes);
WRITE_ONCE(c->_c.mfc_un.res.lastuse, jiffies);

if (ipv6_addr_any(&c->mf6c_origin) && true_vifi >= 0) {
struct mfc6_cache *cache_proxy;
Expand All @@ -2162,7 +2162,7 @@ static void ip6_mr_forward(struct net *net, struct mr_table *mrt,
* Wrong interface: drop packet and (maybe) send PIM assert.
*/
if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev) {
c->_c.mfc_un.res.wrong_if++;
atomic_long_inc(&c->_c.mfc_un.res.wrong_if);

if (true_vifi >= 0 && mrt->mroute_do_assert &&
/* pimsm uses asserts, when switching from RPT to SPT,
Expand Down

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