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%3Ba=su...
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@vger.kernel.org know about it.
From foo@baz Thu Dec 14 11:45:58 CET 2017
From: Eric Dumazet edumazet@google.com Date: Tue, 5 Dec 2017 12:45:56 -0800 Subject: net: remove hlist_nulls_add_tail_rcu()
From: Eric Dumazet edumazet@google.com
[ 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@google.com Reported-by: Alexander Potapenko glider@google.com Acked-by: Craig Gallek kraig@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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@google.com 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