This is a note to let you know that I've just added the patch titled
net: remove hlist_nulls_add_tail_rcu()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-remove-hlist_nulls_add_tail_rcu.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Dec 14 11:45:58 CET 2017
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Tue, 5 Dec 2017 12:45:56 -0800
Subject: net: remove hlist_nulls_add_tail_rcu()
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit d7efc6c11b277d9d80b99b1334a78bfe7d7edf10 ]
Alexander Potapenko reported use of uninitialized memory [1]
This happens when inserting a request socket into TCP ehash,
in __sk_nulls_add_node_rcu(), since sk_reuseport is not initialized.
Bug was added by commit d894ba18d4e4 ("soreuseport: fix ordering for
mixed v4/v6 sockets")
Note that d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6
ordering fix") missed the opportunity to get rid of
hlist_nulls_add_tail_rcu() :
Both UDP sockets and TCP/DCCP listeners no longer use
__sk_nulls_add_node_rcu() for their hash insertion.
Since all other sockets have unique 4-tuple, the reuseport status
has no special meaning, so we can always use hlist_nulls_add_head_rcu()
for them and save few cycles/instructions.
[1]
==================================================================
BUG: KMSAN: use of uninitialized memory in inet_ehash_insert+0xd40/0x1050
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.13.0+ #3288
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:16
dump_stack+0x185/0x1d0 lib/dump_stack.c:52
kmsan_report+0x13f/0x1c0 mm/kmsan/kmsan.c:1016
__msan_warning_32+0x69/0xb0 mm/kmsan/kmsan_instr.c:766
__sk_nulls_add_node_rcu ./include/net/sock.h:684
inet_ehash_insert+0xd40/0x1050 net/ipv4/inet_hashtables.c:413
reqsk_queue_hash_req net/ipv4/inet_connection_sock.c:754
inet_csk_reqsk_queue_hash_add+0x1cc/0x300 net/ipv4/inet_connection_sock.c:765
tcp_conn_request+0x31e7/0x36f0 net/ipv4/tcp_input.c:6414
tcp_v4_conn_request+0x16d/0x220 net/ipv4/tcp_ipv4.c:1314
tcp_rcv_state_process+0x42a/0x7210 net/ipv4/tcp_input.c:5917
tcp_v4_do_rcv+0xa6a/0xcd0 net/ipv4/tcp_ipv4.c:1483
tcp_v4_rcv+0x3de0/0x4ab0 net/ipv4/tcp_ipv4.c:1763
ip_local_deliver_finish+0x6bb/0xcb0 net/ipv4/ip_input.c:216
NF_HOOK ./include/linux/netfilter.h:248
ip_local_deliver+0x3fa/0x480 net/ipv4/ip_input.c:257
dst_input ./include/net/dst.h:477
ip_rcv_finish+0x6fb/0x1540 net/ipv4/ip_input.c:397
NF_HOOK ./include/linux/netfilter.h:248
ip_rcv+0x10f6/0x15c0 net/ipv4/ip_input.c:488
__netif_receive_skb_core+0x36f6/0x3f60 net/core/dev.c:4298
__netif_receive_skb net/core/dev.c:4336
netif_receive_skb_internal+0x63c/0x19c0 net/core/dev.c:4497
napi_skb_finish net/core/dev.c:4858
napi_gro_receive+0x629/0xa50 net/core/dev.c:4889
e1000_receive_skb drivers/net/ethernet/intel/e1000/e1000_main.c:4018
e1000_clean_rx_irq+0x1492/0x1d30
drivers/net/ethernet/intel/e1000/e1000_main.c:4474
e1000_clean+0x43aa/0x5970 drivers/net/ethernet/intel/e1000/e1000_main.c:3819
napi_poll net/core/dev.c:5500
net_rx_action+0x73c/0x1820 net/core/dev.c:5566
__do_softirq+0x4b4/0x8dd kernel/softirq.c:284
invoke_softirq kernel/softirq.c:364
irq_exit+0x203/0x240 kernel/softirq.c:405
exiting_irq+0xe/0x10 ./arch/x86/include/asm/apic.h:638
do_IRQ+0x15e/0x1a0 arch/x86/kernel/irq.c:263
common_interrupt+0x86/0x86
Fixes: d894ba18d4e4 ("soreuseport: fix ordering for mixed v4/v6 sockets")
Fixes: d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6 ordering fix")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: Alexander Potapenko <glider@xxxxxxxxxx>
Acked-by: Craig Gallek <kraig@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/rculist_nulls.h | 38 --------------------------------------
include/net/sock.h | 6 +-----
2 files changed, 1 insertion(+), 43 deletions(-)
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -100,44 +100,6 @@ static inline void hlist_nulls_add_head_
}
/**
- * hlist_nulls_add_tail_rcu
- * @n: the element to add to the hash list.
- * @h: the list to add to.
- *
- * Description:
- * Adds the specified element to the end of the specified hlist_nulls,
- * while permitting racing traversals. NOTE: tail insertion requires
- * list traversal.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
- * or hlist_nulls_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * hlist_nulls_for_each_entry_rcu(), used to prevent memory-consistency
- * problems on Alpha CPUs. Regardless of the type of CPU, the
- * list-traversal primitive must be guarded by rcu_read_lock().
- */
-static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
- struct hlist_nulls_head *h)
-{
- struct hlist_nulls_node *i, *last = NULL;
-
- for (i = hlist_nulls_first_rcu(h); !is_a_nulls(i);
- i = hlist_nulls_next_rcu(i))
- last = i;
-
- if (last) {
- n->next = last->next;
- n->pprev = &last->next;
- rcu_assign_pointer(hlist_nulls_next_rcu(last), n);
- } else {
- hlist_nulls_add_head_rcu(n, h);
- }
-}
-
-/**
* hlist_nulls_for_each_entry_rcu - iterate over rcu list of given type
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_nulls_node to use as a loop cursor.
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -648,11 +648,7 @@ static inline void sk_add_node_rcu(struc
static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
{
- if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
- sk->sk_family == AF_INET6)
- hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
- else
- hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
+ hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
}
static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are
queue-4.9/net-packet-fix-a-race-in-packet_bind-and-packet_notifier.patch
queue-4.9/packet-fix-crash-in-fanout_demux_rollover.patch
queue-4.9/net-remove-hlist_nulls_add_tail_rcu.patch
queue-4.9/tcp-dccp-block-bh-before-arming-time_wait-timer.patch