diff options
Diffstat (limited to 'patches/net-add-back-the-missing-serialization-in-ip_send_un.patch')
| -rw-r--r-- | patches/net-add-back-the-missing-serialization-in-ip_send_un.patch | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/patches/net-add-back-the-missing-serialization-in-ip_send_un.patch b/patches/net-add-back-the-missing-serialization-in-ip_send_un.patch new file mode 100644 index 000000000000..2c83f004fc3b --- /dev/null +++ b/patches/net-add-back-the-missing-serialization-in-ip_send_un.patch @@ -0,0 +1,87 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Wed, 31 Aug 2016 17:21:56 +0200 +Subject: [PATCH] net: add back the missing serialization in + ip_send_unicast_reply() +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +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> +--- + net/ipv4/tcp_ipv4.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +--- 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> +@@ -565,6 +566,7 @@ void tcp_v4_send_check(struct sock *sk, + } + EXPORT_SYMBOL(tcp_v4_send_check); + ++static DEFINE_LOCAL_IRQ_LOCK(tcp_sk_lock); + /* + * This routine will send an RST to the other tcp. + * +@@ -689,10 +691,13 @@ static void tcp_v4_send_reset(const stru + offsetof(struct inet_timewait_sock, tw_bound_dev_if)); + + arg.tos = ip_hdr(skb)->tos; ++ ++ local_lock(tcp_sk_lock); + ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), + skb, &TCP_SKB_CB(skb)->header.h4.opt, + ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, + &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); +@@ -774,10 +779,12 @@ static void tcp_v4_send_ack(struct net * + if (oif) + arg.bound_dev_if = oif; + arg.tos = tos; ++ local_lock(tcp_sk_lock); + ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), + skb, &TCP_SKB_CB(skb)->header.h4.opt, + ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, + &arg, arg.iov[0].iov_len); ++ local_unlock(tcp_sk_lock); + + TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); + } |