diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-08-31 17:21:56 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2016-11-16 14:23:22 -0500 |
| commit | f4fd98d0a20e2e45f714f6caba37c94fc4efe616 (patch) | |
| tree | 676901f5edc03f60cb7ceb1be24cefdf4f1a9f55 | |
| parent | 22095108a2a00433d43adfa5851bb58187f28573 (diff) | |
| download | linux-rt-f4fd98d0a20e2e45f714f6caba37c94fc4efe616.tar.gz | |
net: add back the missing serialization in ip_send_unicast_reply()
Some time ago Sami Pietikäinen reported a crash on -RT in
ip_send_unicast_reply() which was later fixed by Nicholas Mc Guire
(v3.12.8-rt11). Later (v3.18.8) the code was reworked and I dropped the
patch. As it turns out it was mistake.
I have reports that the same crash is possible with a similar backtrace.
It seems that vanilla protects access to this_cpu_ptr() via
local_bh_disable(). This does not work the on -RT since we can have
NET_RX and NET_TX running in parallel on the same CPU.
This is brings back the old locks.
|Unable to handle kernel NULL pointer dereference at virtual address 00000010
|PC is at __ip_make_skb+0x198/0x3e8
|[<c04e39d8>] (__ip_make_skb) from [<c04e3ca8>] (ip_push_pending_frames+0x20/0x40)
|[<c04e3ca8>] (ip_push_pending_frames) from [<c04e3ff0>] (ip_send_unicast_reply+0x210/0x22c)
|[<c04e3ff0>] (ip_send_unicast_reply) from [<c04fbb54>] (tcp_v4_send_reset+0x190/0x1c0)
|[<c04fbb54>] (tcp_v4_send_reset) from [<c04fcc1c>] (tcp_v4_do_rcv+0x22c/0x288)
|[<c04fcc1c>] (tcp_v4_do_rcv) from [<c0474364>] (release_sock+0xb4/0x150)
|[<c0474364>] (release_sock) from [<c04ed904>] (tcp_close+0x240/0x454)
|[<c04ed904>] (tcp_close) from [<c0511408>] (inet_release+0x74/0x7c)
|[<c0511408>] (inet_release) from [<c0470728>] (sock_release+0x30/0xb0)
|[<c0470728>] (sock_release) from [<c0470abc>] (sock_close+0x1c/0x24)
|[<c0470abc>] (sock_close) from [<c0115ec4>] (__fput+0xe8/0x20c)
|[<c0115ec4>] (__fput) from [<c0116050>] (____fput+0x18/0x1c)
|[<c0116050>] (____fput) from [<c0058138>] (task_work_run+0xa4/0xb8)
|[<c0058138>] (task_work_run) from [<c0011478>] (do_work_pending+0xd0/0xe4)
|[<c0011478>] (do_work_pending) from [<c000e740>] (work_pending+0xc/0x20)
|Code: e3530001 8a000001 e3a00040 ea000011 (e5973010)
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6e212f7a5782..984cfbad062d 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -62,6 +62,7 @@ #include <linux/init.h> #include <linux/times.h> #include <linux/slab.h> +#include <linux/locallock.h> #include <net/net_namespace.h> #include <net/icmp.h> @@ -569,6 +570,7 @@ int tcp_v4_gso_send_check(struct sk_buff *skb) return 0; } +static DEFINE_LOCAL_IRQ_LOCK(tcp_sk_lock); /* * This routine will send an RST to the other tcp. * @@ -686,8 +688,11 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) net = dev_net(skb_dst(skb)->dev); arg.tos = ip_hdr(skb)->tos; + + local_lock(tcp_sk_lock); ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr, &arg, arg.iov[0].iov_len); + local_unlock(tcp_sk_lock); TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS); @@ -769,8 +774,10 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, if (oif) arg.bound_dev_if = oif; arg.tos = tos; + local_lock(tcp_sk_lock); ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr, &arg, arg.iov[0].iov_len); + local_unlock(tcp_sk_lock); TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); } |