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net: Fix RCU splat in af_key
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Hit the following splat testing VRF change for ipsec:

[  113.475692] ===============================
[  113.476194] [ INFO: suspicious RCU usage. ]
[  113.476667] 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED Not tainted
[  113.477545] -------------------------------
[  113.478013] /work/monster-14/dsa/kernel.git/include/linux/rcupdate.h:568 Illegal context switch in RCU read-side critical section!
[  113.479288]
[  113.479288] other info that might help us debug this:
[  113.479288]
[  113.480207]
[  113.480207] rcu_scheduler_active = 1, debug_locks = 1
[  113.480931] 2 locks held by setkey/6829:
[  113.481371]  #0:  (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff814e9887>] pfkey_sendmsg+0xfb/0x213
[  113.482509]  #1:  (rcu_read_lock){......}, at: [<ffffffff814e767f>] rcu_read_lock+0x0/0x6e
[  113.483509]
[  113.483509] stack backtrace:
[  113.484041] CPU: 0 PID: 6829 Comm: setkey Not tainted 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED
[  113.485422] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014
[  113.486845]  0000000000000001 ffff88001d4c7a98 ffffffff81518af2 ffffffff81086962
[  113.487732]  ffff88001d538480 ffff88001d4c7ac8 ffffffff8107ae75 ffffffff8180a154
[  113.488628]  0000000000000b30 0000000000000000 00000000000000d0 ffff88001d4c7ad8
[  113.489525] Call Trace:
[  113.489813]  [<ffffffff81518af2>] dump_stack+0x4c/0x65
[  113.490389]  [<ffffffff81086962>] ? console_unlock+0x3d6/0x405
[  113.491039]  [<ffffffff8107ae75>] lockdep_rcu_suspicious+0xfa/0x103
[  113.491735]  [<ffffffff81064032>] rcu_preempt_sleep_check+0x45/0x47
[  113.492442]  [<ffffffff8106404d>] ___might_sleep+0x19/0x1c8
[  113.493077]  [<ffffffff81064268>] __might_sleep+0x6c/0x82
[  113.493681]  [<ffffffff81133190>] cache_alloc_debugcheck_before.isra.50+0x1d/0x24
[  113.494508]  [<ffffffff81134876>] kmem_cache_alloc+0x31/0x18f
[  113.495149]  [<ffffffff814012b5>] skb_clone+0x64/0x80
[  113.495712]  [<ffffffff814e6f71>] pfkey_broadcast_one+0x3d/0xff
[  113.496380]  [<ffffffff814e7b84>] pfkey_broadcast+0xb5/0x11e
[  113.497024]  [<ffffffff814e82d1>] pfkey_register+0x191/0x1b1
[  113.497653]  [<ffffffff814e9770>] pfkey_process+0x162/0x17e
[  113.498274]  [<ffffffff814e9895>] pfkey_sendmsg+0x109/0x213

In pfkey_sendmsg the net mutex is taken and then pfkey_broadcast takes
the RCU lock.

Since pfkey_broadcast takes the RCU lock the allocation argument is
pointless since GFP_ATOMIC must be used between the rcu_read_{,un}lock.
The one call outside of rcu can be done with GFP_KERNEL.

Fixes: 7f6b9db ("af_key: locking change")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@davem330
David Ahern authored and davem330 committed Aug 24, 2015
1 parent b6df7d6 commit ba51b6b
Showing 1 changed file with 23 additions and 23 deletions.
46 changes: 23 additions & 23 deletions net/key/af_key.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -219,7 +219,7 @@ static int pfkey_broadcast_one(struct sk_buff *skb, struct sk_buff **skb2,
#define BROADCAST_ONE 1
#define BROADCAST_REGISTERED 2
#define BROADCAST_PROMISC_ONLY 4
static int pfkey_broadcast(struct sk_buff *skb, gfp_t allocation,
static int pfkey_broadcast(struct sk_buff *skb,
int broadcast_flags, struct sock *one_sk,
struct net *net)
{
Expand All @@ -244,7 +244,7 @@ static int pfkey_broadcast(struct sk_buff *skb, gfp_t allocation,
* socket.
*/
if (pfk->promisc)
pfkey_broadcast_one(skb, &skb2, allocation, sk);
pfkey_broadcast_one(skb, &skb2, GFP_ATOMIC, sk);

/* the exact target will be processed later */
if (sk == one_sk)
Expand All @@ -259,7 +259,7 @@ static int pfkey_broadcast(struct sk_buff *skb, gfp_t allocation,
continue;
}

err2 = pfkey_broadcast_one(skb, &skb2, allocation, sk);
err2 = pfkey_broadcast_one(skb, &skb2, GFP_ATOMIC, sk);

/* Error is cleare after succecful sending to at least one
* registered KM */
Expand All @@ -269,7 +269,7 @@ static int pfkey_broadcast(struct sk_buff *skb, gfp_t allocation,
rcu_read_unlock();

if (one_sk != NULL)
err = pfkey_broadcast_one(skb, &skb2, allocation, one_sk);
err = pfkey_broadcast_one(skb, &skb2, GFP_KERNEL, one_sk);

kfree_skb(skb2);
kfree_skb(skb);
Expand All @@ -292,7 +292,7 @@ static int pfkey_do_dump(struct pfkey_sock *pfk)
hdr = (struct sadb_msg *) pfk->dump.skb->data;
hdr->sadb_msg_seq = 0;
hdr->sadb_msg_errno = rc;
pfkey_broadcast(pfk->dump.skb, GFP_ATOMIC, BROADCAST_ONE,
pfkey_broadcast(pfk->dump.skb, BROADCAST_ONE,
&pfk->sk, sock_net(&pfk->sk));
pfk->dump.skb = NULL;
}
Expand Down Expand Up @@ -333,7 +333,7 @@ static int pfkey_error(const struct sadb_msg *orig, int err, struct sock *sk)
hdr->sadb_msg_len = (sizeof(struct sadb_msg) /
sizeof(uint64_t));

pfkey_broadcast(skb, GFP_KERNEL, BROADCAST_ONE, sk, sock_net(sk));
pfkey_broadcast(skb, BROADCAST_ONE, sk, sock_net(sk));

return 0;
}
Expand Down Expand Up @@ -1365,7 +1365,7 @@ static int pfkey_getspi(struct sock *sk, struct sk_buff *skb, const struct sadb_

xfrm_state_put(x);

pfkey_broadcast(resp_skb, GFP_KERNEL, BROADCAST_ONE, sk, net);
pfkey_broadcast(resp_skb, BROADCAST_ONE, sk, net);

return 0;
}
Expand Down Expand Up @@ -1452,7 +1452,7 @@ static int key_notify_sa(struct xfrm_state *x, const struct km_event *c)
hdr->sadb_msg_seq = c->seq;
hdr->sadb_msg_pid = c->portid;

pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, xs_net(x));
pfkey_broadcast(skb, BROADCAST_ALL, NULL, xs_net(x));

return 0;
}
Expand Down Expand Up @@ -1565,7 +1565,7 @@ static int pfkey_get(struct sock *sk, struct sk_buff *skb, const struct sadb_msg
out_hdr->sadb_msg_reserved = 0;
out_hdr->sadb_msg_seq = hdr->sadb_msg_seq;
out_hdr->sadb_msg_pid = hdr->sadb_msg_pid;
pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_ONE, sk, sock_net(sk));
pfkey_broadcast(out_skb, BROADCAST_ONE, sk, sock_net(sk));

return 0;
}
Expand Down Expand Up @@ -1670,7 +1670,7 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sad
return -ENOBUFS;
}

pfkey_broadcast(supp_skb, GFP_KERNEL, BROADCAST_REGISTERED, sk, sock_net(sk));
pfkey_broadcast(supp_skb, BROADCAST_REGISTERED, sk, sock_net(sk));

return 0;
}
Expand All @@ -1689,7 +1689,7 @@ static int unicast_flush_resp(struct sock *sk, const struct sadb_msg *ihdr)
hdr->sadb_msg_errno = (uint8_t) 0;
hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));

return pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ONE, sk, sock_net(sk));
return pfkey_broadcast(skb, BROADCAST_ONE, sk, sock_net(sk));
}

static int key_notify_sa_flush(const struct km_event *c)
Expand All @@ -1710,7 +1710,7 @@ static int key_notify_sa_flush(const struct km_event *c)
hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
hdr->sadb_msg_reserved = 0;

pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
pfkey_broadcast(skb, BROADCAST_ALL, NULL, c->net);

return 0;
}
Expand Down Expand Up @@ -1767,7 +1767,7 @@ static int dump_sa(struct xfrm_state *x, int count, void *ptr)
out_hdr->sadb_msg_pid = pfk->dump.msg_portid;

if (pfk->dump.skb)
pfkey_broadcast(pfk->dump.skb, GFP_ATOMIC, BROADCAST_ONE,
pfkey_broadcast(pfk->dump.skb, BROADCAST_ONE,
&pfk->sk, sock_net(&pfk->sk));
pfk->dump.skb = out_skb;

Expand Down Expand Up @@ -1847,7 +1847,7 @@ static int pfkey_promisc(struct sock *sk, struct sk_buff *skb, const struct sadb
new_hdr->sadb_msg_errno = 0;
}

pfkey_broadcast(skb, GFP_KERNEL, BROADCAST_ALL, NULL, sock_net(sk));
pfkey_broadcast(skb, BROADCAST_ALL, NULL, sock_net(sk));
return 0;
}

Expand Down Expand Up @@ -2181,7 +2181,7 @@ static int key_notify_policy(struct xfrm_policy *xp, int dir, const struct km_ev
out_hdr->sadb_msg_errno = 0;
out_hdr->sadb_msg_seq = c->seq;
out_hdr->sadb_msg_pid = c->portid;
pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_ALL, NULL, xp_net(xp));
pfkey_broadcast(out_skb, BROADCAST_ALL, NULL, xp_net(xp));
return 0;

}
Expand Down Expand Up @@ -2401,7 +2401,7 @@ static int key_pol_get_resp(struct sock *sk, struct xfrm_policy *xp, const struc
out_hdr->sadb_msg_errno = 0;
out_hdr->sadb_msg_seq = hdr->sadb_msg_seq;
out_hdr->sadb_msg_pid = hdr->sadb_msg_pid;
pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_ONE, sk, xp_net(xp));
pfkey_broadcast(out_skb, BROADCAST_ONE, sk, xp_net(xp));
err = 0;

out:
Expand Down Expand Up @@ -2655,7 +2655,7 @@ static int dump_sp(struct xfrm_policy *xp, int dir, int count, void *ptr)
out_hdr->sadb_msg_pid = pfk->dump.msg_portid;

if (pfk->dump.skb)
pfkey_broadcast(pfk->dump.skb, GFP_ATOMIC, BROADCAST_ONE,
pfkey_broadcast(pfk->dump.skb, BROADCAST_ONE,
&pfk->sk, sock_net(&pfk->sk));
pfk->dump.skb = out_skb;

Expand Down Expand Up @@ -2708,7 +2708,7 @@ static int key_notify_policy_flush(const struct km_event *c)
hdr->sadb_msg_satype = SADB_SATYPE_UNSPEC;
hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
hdr->sadb_msg_reserved = 0;
pfkey_broadcast(skb_out, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
pfkey_broadcast(skb_out, BROADCAST_ALL, NULL, c->net);
return 0;

}
Expand Down Expand Up @@ -2770,7 +2770,7 @@ static int pfkey_process(struct sock *sk, struct sk_buff *skb, const struct sadb
void *ext_hdrs[SADB_EXT_MAX];
int err;

pfkey_broadcast(skb_clone(skb, GFP_KERNEL), GFP_KERNEL,
pfkey_broadcast(skb_clone(skb, GFP_KERNEL),
BROADCAST_PROMISC_ONLY, NULL, sock_net(sk));

memset(ext_hdrs, 0, sizeof(ext_hdrs));
Expand Down Expand Up @@ -2992,7 +2992,7 @@ static int key_notify_sa_expire(struct xfrm_state *x, const struct km_event *c)
out_hdr->sadb_msg_seq = 0;
out_hdr->sadb_msg_pid = 0;

pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_REGISTERED, NULL, xs_net(x));
pfkey_broadcast(out_skb, BROADCAST_REGISTERED, NULL, xs_net(x));
return 0;
}

Expand Down Expand Up @@ -3182,7 +3182,7 @@ static int pfkey_send_acquire(struct xfrm_state *x, struct xfrm_tmpl *t, struct
xfrm_ctx->ctx_len);
}

return pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_REGISTERED, NULL, xs_net(x));
return pfkey_broadcast(skb, BROADCAST_REGISTERED, NULL, xs_net(x));
}

static struct xfrm_policy *pfkey_compile_policy(struct sock *sk, int opt,
Expand Down Expand Up @@ -3380,7 +3380,7 @@ static int pfkey_send_new_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr,
n_port->sadb_x_nat_t_port_port = sport;
n_port->sadb_x_nat_t_port_reserved = 0;

return pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_REGISTERED, NULL, xs_net(x));
return pfkey_broadcast(skb, BROADCAST_REGISTERED, NULL, xs_net(x));
}

#ifdef CONFIG_NET_KEY_MIGRATE
Expand Down Expand Up @@ -3572,7 +3572,7 @@ static int pfkey_send_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
}

/* broadcast migrate message to sockets */
pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, &init_net);
pfkey_broadcast(skb, BROADCAST_ALL, NULL, &init_net);

return 0;

Expand Down

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