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  1. 02 Oct, 2019 6 commits
    • Tuong Lien's avatar
      tipc: fix unlimited bundling of small messages · e95584a8
      Tuong Lien authored 
      We have identified a problem with the "oversubscription" policy in the
link transmission code.

When small messages are transmitted, and the sending link has reached
the transmit window limit, those messages will be bundled and put into
the link backlog queue. However, bundles of data messages are counted
at the 'CRITICAL' level, so that the counter for that level, instead of
the counter for the real, bundled message's level is the one being
increased.
Subsequent, to-be-bundled data messages at non-CRITICAL levels continue
to be tested against the unchanged counter for their own level, while
contributing to an unrestrained increase at the CRITICAL backlog level.

This leaves a gap in congestion control algorithm for small messages
that can result in starvation for other users or a "real" CRITICAL
user. Even that eventually can lead to buffer exhaustion & link reset.

We fix this by keeping a 'target_bskb' buffer pointer at each levels,
then when bundling, we only bundle messages at the same importance
level only. This way, we know exactly how many slots a certain level
have occupied in the queue, so can manage level congestion accurately.

By bundling messages at the same level, we even have more benefits. Let
consider this:
- One socket sends 64-byte messages at the 'CRITICAL' level;
- Another sends 4096-byte messages at the 'LOW' level;

When a 64-byte message comes and is bundled the first time, we put the
overhead of message bundle to it (+ 40-byte header, data copy, etc.)
for later use, but the next message can be a 4096-byte one that cannot
be bundled to the previous one. This means the last bundle carries only
one payload message which is totally inefficient, as for the receiver
also! Later on, another 64-byte message comes, now we make a new bundle
and the same story repeats...

With the new bundling algorithm, this will not happen, the 64-byte
messages will be bundled together even when the 4096-byte message(s)
comes in between. However, if the 4096-byte messages are sent at the
same level i.e. 'CRITICAL', the bundling algorithm will again cause the
same overhead.

Also, the same will happen even with only one socket sending small
messages at a rate close to the link transmit's one, so that, when one
message is bundled, it's transmitted shortly. Then, another message
comes, a new bundle is created and so on...

We will solve this issue radically by another patch.

Fixes: 365ad353 ("tipc: reduce risk of user starvation during link congestion")
Reported-by: default avatarHoang Le <hoang.h.le@dektech.com.au>
Acked-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarTuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e95584a8
    • Dongli Zhang's avatar
      xen-netfront: do not use ~0U as error return value for xennet_fill_frags() · a761129e
      Dongli Zhang authored 
      xennet_fill_frags() uses ~0U as return value when the sk_buff is not able
to cache extra fragments. This is incorrect because the return type of
xennet_fill_frags() is RING_IDX and 0xffffffff is an expected value for
ring buffer index.

In the situation when the rsp_cons is approaching 0xffffffff, the return
value of xennet_fill_frags() may become 0xffffffff which xennet_poll() (the
caller) would regard as error. As a result, queue->rx.rsp_cons is set
incorrectly because it is updated only when there is error. If there is no
error, xennet_poll() would be responsible to update queue->rx.rsp_cons.
Finally, queue->rx.rsp_cons would point to the rx ring buffer entries whose
queue->rx_skbs[i] and queue->grant_rx_ref[i] are already cleared to NULL.
This leads to NULL pointer access in the next iteration to process rx ring
buffer entries.

The symptom is similar to the one fixed in
commit 00b36850 ("xen-netfront: do not assume sk_buff_head list is
empty in error handling").

This patch changes the return type of xennet_fill_frags() to indicate
whether it is successful or failed. The queue->rx.rsp_cons will be
always updated inside this function.

Fixes: ad4f15dc ("xen/netfront: don't bug in case of too many frags")
Signed-off-by: default avatarDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a761129e
    • David Ahern's avatar
      ipv6: Handle race in addrconf_dad_work · a3ce2a21
      David Ahern authored 
      Rajendra reported a kernel panic when a link was taken down:

[ 6870.263084] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
[ 6870.271856] IP: [<ffffffff8efc5764>] __ipv6_ifa_notify+0x154/0x290

<snip>

[ 6870.570501] Call Trace:
[ 6870.573238] [<ffffffff8efc58c6>] ? ipv6_ifa_notify+0x26/0x40
[ 6870.579665] [<ffffffff8efc98ec>] ? addrconf_dad_completed+0x4c/0x2c0
[ 6870.586869] [<ffffffff8efe70c6>] ? ipv6_dev_mc_inc+0x196/0x260
[ 6870.593491] [<ffffffff8efc9c6a>] ? addrconf_dad_work+0x10a/0x430
[ 6870.600305] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.606732] [<ffffffff8ea93a7a>] ? process_one_work+0x18a/0x430
[ 6870.613449] [<ffffffff8ea93d6d>] ? worker_thread+0x4d/0x490
[ 6870.619778] [<ffffffff8ea93d20>] ? process_one_work+0x430/0x430
[ 6870.626495] [<ffffffff8ea99dd9>] ? kthread+0xd9/0xf0
[ 6870.632145] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.638573] [<ffffffff8ea99d00>] ? kthread_park+0x60/0x60
[ 6870.644707] [<ffffffff8f01ae77>] ? ret_from_fork+0x57/0x70
[ 6870.650936] Code: 31 c0 31 d2 41 b9 20 00 08 02 b9 09 00 00 0

addrconf_dad_work is kicked to be scheduled when a device is brought
up. There is a race between addrcond_dad_work getting scheduled and
taking the rtnl lock and a process taking the link down (under rtnl).
The latter removes the host route from the inet6_addr as part of
addrconf_ifdown which is run for NETDEV_DOWN. The former attempts
to use the host route in ipv6_ifa_notify. If the down event removes
the host route due to the race to the rtnl, then the BUG listed above
occurs.

This scenario does not occur when the ipv6 address is not kept
(net.ipv6.conf.all.keep_addr_on_down = 0) as addrconf_ifdown sets the
state of the ifp to DEAD. Handle when the addresses are kept by checking
IF_READY which is reset by addrconf_ifdown.

The 'dead' flag for an inet6_addr is set only under rtnl, in
addrconf_ifdown and it means the device is getting removed (or IPv6 is
disabled). The interesting cases for changing the idev flag are
addrconf_notify (NETDEV_UP and NETDEV_CHANGE) and addrconf_ifdown
(reset the flag). The former does not have the idev lock - only rtnl;
the latter has both. Based on that the existing dead + IF_READY check
can be moved to right after the rtnl_lock in addrconf_dad_work.

Fixes: f1705ec1 ("net: ipv6: Make address flushing on ifdown optional")
Reported-by: default avatarRajendra Dendukuri <rajendra.dendukuri@broadcom.com>
Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a3ce2a21
    • Eric Dumazet's avatar
      tcp: adjust rto_base in retransmits_timed_out() · 3256a2d6
      Eric Dumazet authored 
      The cited commit exposed an old retransmits_timed_out() bug
which assumed it could call tcp_model_timeout() with
TCP_RTO_MIN as rto_base for all states.

But flows in SYN_SENT or SYN_RECV state uses a different
RTO base (1 sec instead of 200 ms, unless BPF choses
another value)

This caused a reduction of SYN retransmits from 6 to 4 with
the default /proc/sys/net/ipv4/tcp_syn_retries value.

Fixes: a41e8a88 ("tcp: better handle TCP_USER_TIMEOUT in SYN_SENT state")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Marek Majkowski <marek@cloudflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3256a2d6
    • Dexuan Cui's avatar
      vsock: Fix a lockdep warning in __vsock_release() · 0d9138ff
      Dexuan Cui authored 
      Lockdep is unhappy if two locks from the same class are held.

Fix the below warning for hyperv and virtio sockets (vmci socket code
doesn't have the issue) by using lock_sock_nested() when __vsock_release()
is called recursively:

============================================
WARNING: possible recursive locking detected
5.3.0+ #1 Not tainted
--------------------------------------------
server/1795 is trying to acquire lock:
ffff8880c5158990 (sk_lock-AF_VSOCK){+.+.}, at: hvs_release+0x10/0x120 [hv_sock]

but task is already holding lock:
ffff8880c5158150 (sk_lock-AF_VSOCK){+.+.}, at: __vsock_release+0x2e/0xf0 [vsock]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(sk_lock-AF_VSOCK);
  lock(sk_lock-AF_VSOCK);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by server/1795:
 #0: ffff8880c5d05ff8 (&sb->s_type->i_mutex_key#10){+.+.}, at: __sock_release+0x2d/0xa0
 #1: ffff8880c5158150 (sk_lock-AF_VSOCK){+.+.}, at: __vsock_release+0x2e/0xf0 [vsock]

stack backtrace:
CPU: 5 PID: 1795 Comm: server Not tainted 5.3.0+ #1
Call Trace:
 dump_stack+0x67/0x90
 __lock_acquire.cold.67+0xd2/0x20b
 lock_acquire+0xb5/0x1c0
 lock_sock_nested+0x6d/0x90
 hvs_release+0x10/0x120 [hv_sock]
 __vsock_release+0x24/0xf0 [vsock]
 __vsock_release+0xa0/0xf0 [vsock]
 vsock_release+0x12/0x30 [vsock]
 __sock_release+0x37/0xa0
 sock_close+0x14/0x20
 __fput+0xc1/0x250
 task_work_run+0x98/0xc0
 do_exit+0x344/0xc60
 do_group_exit+0x47/0xb0
 get_signal+0x15c/0xc50
 do_signal+0x30/0x720
 exit_to_usermode_loop+0x50/0xa0
 do_syscall_64+0x24e/0x270
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f4184e85f31
Tested-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0d9138ff
    • Johan Hovold's avatar
      hso: fix NULL-deref on tty open · 8353da9f
      Johan Hovold authored 
      Fix NULL-pointer dereference on tty open due to a failure to handle a
missing interrupt-in endpoint when probing modem ports:

	BUG: kernel NULL pointer dereference, address: 0000000000000006
	...
	RIP: 0010:tiocmget_submit_urb+0x1c/0xe0 [hso]
	...
	Call Trace:
	hso_start_serial_device+0xdc/0x140 [hso]
	hso_serial_open+0x118/0x1b0 [hso]
	tty_open+0xf1/0x490

Fixes: 542f5482 ("tty: Modem functions for the HSO driver")
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8353da9f
  3. 01 Oct, 2019 31 commits
  5. 30 Sep, 2019 3 commits
    • Haishuang Yan's avatar
      erspan: remove the incorrect mtu limit for erspan · 0e141f75
      Haishuang Yan authored 
      erspan driver calls ether_setup(), after commit 61e84623
("net: centralize net_device min/max MTU checking"), the range
of mtu is [min_mtu, max_mtu], which is [68, 1500] by default.

It causes the dev mtu of the erspan device to not be greater
than 1500, this limit value is not correct for ipgre tap device.

Tested:
Before patch:
# ip link set erspan0 mtu 1600
Error: mtu greater than device maximum.
After patch:
# ip link set erspan0 mtu 1600
# ip -d link show erspan0
21: erspan0@NONE: <BROADCAST,MULTICAST> mtu 1600 qdisc noop state DOWN
mode DEFAULT group default qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 0

Fixes: 61e84623 ("net: centralize net_device min/max MTU checking")
Signed-off-by: default avatarHaishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0e141f75
    • Eric Dumazet's avatar
      sch_cbq: validate TCA_CBQ_WRROPT to avoid crash · e9789c7c
      Eric Dumazet authored 
      syzbot reported a crash in cbq_normalize_quanta() caused
by an out of range cl->priority.

iproute2 enforces this check, but malicious users do not.

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN PTI
Modules linked in:
CPU: 1 PID: 26447 Comm: syz-executor.1 Not tainted 5.3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:cbq_normalize_quanta.part.0+0x1fd/0x430 net/sched/sch_cbq.c:902
RSP: 0018:ffff8801a5c333b0 EFLAGS: 00010206
RAX: 0000000020000003 RBX: 00000000fffffff8 RCX: ffffc9000712f000
RDX: 00000000000043bf RSI: ffffffff83be8962 RDI: 0000000100000018
RBP: ffff8801a5c33420 R08: 000000000000003a R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000002ef
R13: ffff88018da95188 R14: dffffc0000000000 R15: 0000000000000015
FS:  00007f37d26b1700(0000) GS:ffff8801dad00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004c7cec CR3: 00000001bcd0a006 CR4: 00000000001626f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 [<ffffffff83be9d57>] cbq_normalize_quanta include/net/pkt_sched.h:27 [inline]
 [<ffffffff83be9d57>] cbq_addprio net/sched/sch_cbq.c:1097 [inline]
 [<ffffffff83be9d57>] cbq_set_wrr+0x2d7/0x450 net/sched/sch_cbq.c:1115
 [<ffffffff83bee8a7>] cbq_change_class+0x987/0x225b net/sched/sch_cbq.c:1537
 [<ffffffff83b96985>] tc_ctl_tclass+0x555/0xcd0 net/sched/sch_api.c:2329
 [<ffffffff83a84655>] rtnetlink_rcv_msg+0x485/0xc10 net/core/rtnetlink.c:5248
 [<ffffffff83cadf0a>] netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2510
 [<ffffffff83a7db6d>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5266
 [<ffffffff83cac2c6>] netlink_unicast_kernel net/netlink/af_netlink.c:1324 [inline]
 [<ffffffff83cac2c6>] netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1350
 [<ffffffff83cacd4a>] netlink_sendmsg+0x89a/0xd50 net/netlink/af_netlink.c:1939
 [<ffffffff8399d46e>] sock_sendmsg_nosec net/socket.c:673 [inline]
 [<ffffffff8399d46e>] sock_sendmsg+0x12e/0x170 net/socket.c:684
 [<ffffffff8399f1fd>] ___sys_sendmsg+0x81d/0x960 net/socket.c:2359
 [<ffffffff839a2d05>] __sys_sendmsg+0x105/0x1d0 net/socket.c:2397
 [<ffffffff839a2df9>] SYSC_sendmsg net/socket.c:2406 [inline]
 [<ffffffff839a2df9>] SyS_sendmsg+0x29/0x30 net/socket.c:2404
 [<ffffffff8101ccc8>] do_syscall_64+0x528/0x770 arch/x86/entry/common.c:305
 [<ffffffff84400091>] entry_SYSCALL_64_after_hwframe+0x42/0xb7

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e9789c7c
    • Michal Vokáč's avatar
      net: dsa: qca8k: Use up to 7 ports for all operations · 7ae6d93c
      Michal Vokáč authored 
      The QCA8K family supports up to 7 ports. So use the existing
QCA8K_NUM_PORTS define to allocate the switch structure and limit all
operations with the switch ports.

This was not an issue until commit 0394a63a ("net: dsa: enable and
disable all ports") disabled all unused ports. Since the unused ports 7-11
are outside of the correct register range on this switch some registers
were rewritten with invalid content.

Fixes: 6b93fb46 ("net-next: dsa: add new driver for qca8xxx family")
Fixes: a0c02161 ("net: dsa: variable number of ports")
Fixes: 0394a63a ("net: dsa: enable and disable all ports")
Signed-off-by: default avatarMichal Vokáč <michal.vokac@ysoft.com>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7ae6d93c
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