linux-toradex.git/net, branch v3.4.105

l2tp: fix race while getting PMTU on PPP pseudo-wire

2014-12-01T10:02:45+00:00

commit eed4d839b0cdf9d84b0a9bc63de90fd5e1e886fb upstream.

Use dst_entry held by sk_dst_get() to retrieve tunnel's PMTU.

The dst_mtu(__sk_dst_get(tunnel->sock)) call was racy. __sk_dst_get()
could return NULL if tunnel->sock->sk_dst_cache was reset just before the
call, thus making dst_mtu() dereference a NULL pointer:

[ 1937.661598] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
[ 1937.664005] IP: [] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
[ 1937.664005] PGD daf0c067 PUD d9f93067 PMD 0
[ 1937.664005] Oops: 0000 [#1] SMP
[ 1937.664005] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core ip6table_filter ip6_tables iptable_filter ip_tables ebtable_nat ebtables x_tables udp_tunnel pppoe pppox ppp_generic slhc deflate ctr twofish_generic twofish_x86_64_3way xts lrw gf128mul glue_helper twofish_x86_64 twofish_common blowfish_generic blowfish_x86_64 blowfish_common des_generic cbc xcbc rmd160 sha512_generic hmac crypto_null af_key xfrm_algo 8021q garp bridge stp llc tun atmtcp clip atm ext3 mbcache jbd iTCO_wdt coretemp kvm_intel iTCO_vendor_support kvm pcspkr evdev ehci_pci lpc_ich mfd_core i5400_edac edac_core i5k_amb shpchp button processor thermal_sys xfs crc32c_generic libcrc32c dm_mod usbhid sg hid sr_mod sd_mod cdrom crc_t10dif crct10dif_common ata_generic ahci ata_piix tg3 libahci libata uhci_hcd ptp ehci_hcd pps_core usbcore scsi_mod libphy usb_common [last unloaded: l2tp_core]
[ 1937.664005] CPU: 0 PID: 10022 Comm: l2tpstress Tainted: G           O   3.17.0-rc1 #1
[ 1937.664005] Hardware name: HP ProLiant DL160 G5, BIOS O12 08/22/2008
[ 1937.664005] task: ffff8800d8fda790 ti: ffff8800c43c4000 task.ti: ffff8800c43c4000
[ 1937.664005] RIP: 0010:[]  [] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
[ 1937.664005] RSP: 0018:ffff8800c43c7de8  EFLAGS: 00010282
[ 1937.664005] RAX: ffff8800da8a7240 RBX: ffff8800d8c64600 RCX: 000001c325a137b5
[ 1937.664005] RDX: 8c6318c6318c6320 RSI: 000000000000010c RDI: 0000000000000000
[ 1937.664005] RBP: ffff8800c43c7ea8 R08: 0000000000000000 R09: 0000000000000000
[ 1937.664005] R10: ffffffffa048e2c0 R11: ffff8800d8c64600 R12: ffff8800ca7a5000
[ 1937.664005] R13: ffff8800c439bf40 R14: 000000000000000c R15: 0000000000000009
[ 1937.664005] FS:  00007fd7f610f700(0000) GS:ffff88011a600000(0000) knlGS:0000000000000000
[ 1937.664005] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1937.664005] CR2: 0000000000000020 CR3: 00000000d9d75000 CR4: 00000000000027e0
[ 1937.664005] Stack:
[ 1937.664005]  ffffffffa049da80 ffff8800d8fda790 000000000000005b ffff880000000009
[ 1937.664005]  ffff8800daf3f200 0000000000000003 ffff8800c43c7e48 ffffffff81109b57
[ 1937.664005]  ffffffff81109b0e ffffffff8114c566 0000000000000000 0000000000000000
[ 1937.664005] Call Trace:
[ 1937.664005]  [] ? pppol2tp_connect+0x235/0x41e [l2tp_ppp]
[ 1937.664005]  [] ? might_fault+0x9e/0xa5
[ 1937.664005]  [] ? might_fault+0x55/0xa5
[ 1937.664005]  [] ? rcu_read_unlock+0x1c/0x26
[ 1937.664005]  [] SYSC_connect+0x87/0xb1
[ 1937.664005]  [] ? sysret_check+0x1b/0x56
[ 1937.664005]  [] ? trace_hardirqs_on_caller+0x145/0x1a1
[ 1937.664005]  [] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 1937.664005]  [] ? spin_lock+0x9/0xb
[ 1937.664005]  [] SyS_connect+0x9/0xb
[ 1937.664005]  [] system_call_fastpath+0x16/0x1b
[ 1937.664005] Code: 10 2a 84 81 e8 65 76 bd e0 65 ff 0c 25 10 bb 00 00 4d 85 ed 74 37 48 8b 85 60 ff ff ff 48 8b 80 88 01 00 00 48 8b b8 10 02 00 00 <48> 8b 47 20 ff 50 20 85 c0 74 0f 83 e8 28 89 83 10 01 00 00 89
[ 1937.664005] RIP  [] pppol2tp_connect+0x33d/0x41e [l2tp_ppp]
[ 1937.664005]  RSP 
[ 1937.664005] CR2: 0000000000000020
[ 1939.559375] ---[ end trace 82d44500f28f8708 ]---

Fixes: f34c4a35d879 ("l2tp: take PMTU from tunnel UDP socket")
Signed-off-by: Guillaume Nault 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Cc: Guillaume Nault 
Signed-off-by: Zefan Li

net: Do not enable tx-nocache-copy by default

2014-12-01T10:02:45+00:00

commit cdb3f4a31b64c3a1c6eef40bc01ebc9594c58a8c upstream.

There are many cases where this feature does not improve performance or even
reduces it.

For example, here are the results from tests that I've run using 3.12.6 on one
Intel Xeon W3565 and one i7 920 connected by ixgbe adapters. The results are
from the Xeon, but they're similar on the i7. All numbers report the
mean±stddev over 10 runs of 10s.

1) latency tests similar to what is described in "c6e1a0d net: Allow no-cache
copy from user on transmit"
There is no statistically significant difference between tx-nocache-copy
on/off.
nic irqs spread out (one queue per cpu)

200x netperf -r 1400,1
tx-nocache-copy off
        692000±1000 tps
        50/90/95/99% latency (us): 275±2/643.8±0.4/799±1/2474.4±0.3
tx-nocache-copy on
        693000±1000 tps
        50/90/95/99% latency (us): 274±1/644.1±0.7/800±2/2474.5±0.7

200x netperf -r 14000,14000
tx-nocache-copy off
        86450±80 tps
        50/90/95/99% latency (us): 334.37±0.02/838±1/2100±20/3990±40
tx-nocache-copy on
        86110±60 tps
        50/90/95/99% latency (us): 334.28±0.01/837±2/2110±20/3990±20

2) single stream throughput tests
tx-nocache-copy leads to higher service demand

                        throughput  cpu0        cpu1        demand
                        (Gb/s)      (Gcycle)    (Gcycle)    (cycle/B)

nic irqs and netperf on cpu0 (1x netperf -T0,0 -t omni -- -d send)

tx-nocache-copy off     9402±5      9.4±0.2                 0.80±0.01
tx-nocache-copy on      9403±3      9.85±0.04               0.838±0.004

nic irqs on cpu0, netperf on cpu1 (1x netperf -T1,1 -t omni -- -d send)

tx-nocache-copy off     9401±5      5.83±0.03   5.0±0.1     0.923±0.007
tx-nocache-copy on      9404±2      5.74±0.03   5.523±0.009 0.958±0.002

As a second example, here are some results from Eric Dumazet with latest
net-next.
tx-nocache-copy also leads to higher service demand

(cpu is Intel(R) Xeon(R) CPU X5660  @ 2.80GHz)

lpq83:~# ./ethtool -K eth0 tx-nocache-copy on
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9407.44   2.50     -1.00    0.522   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       4282.648396 task-clock                #    0.423 CPUs utilized
             9,348 context-switches          #    0.002 M/sec
                88 CPU-migrations            #    0.021 K/sec
               355 page-faults               #    0.083 K/sec
    11,812,797,651 cycles                    #    2.758 GHz                     [82.79%]
     9,020,522,817 stalled-cycles-frontend   #   76.36% frontend cycles idle    [82.54%]
     4,579,889,681 stalled-cycles-backend    #   38.77% backend  cycles idle    [67.33%]
     6,053,172,792 instructions              #    0.51  insns per cycle
                                             #    1.49  stalled cycles per insn [83.64%]
       597,275,583 branches                  #  139.464 M/sec                   [83.70%]
         8,960,541 branch-misses             #    1.50% of all branches         [83.65%]

      10.128990264 seconds time elapsed

lpq83:~# ./ethtool -K eth0 tx-nocache-copy off
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9412.45   2.15     -1.00    0.449   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       2847.375441 task-clock                #    0.281 CPUs utilized
            11,632 context-switches          #    0.004 M/sec
                49 CPU-migrations            #    0.017 K/sec
               354 page-faults               #    0.124 K/sec
     7,646,889,749 cycles                    #    2.686 GHz                     [83.34%]
     6,115,050,032 stalled-cycles-frontend   #   79.97% frontend cycles idle    [83.31%]
     1,726,460,071 stalled-cycles-backend    #   22.58% backend  cycles idle    [66.55%]
     2,079,702,453 instructions              #    0.27  insns per cycle
                                             #    2.94  stalled cycles per insn [83.22%]
       363,773,213 branches                  #  127.757 M/sec                   [83.29%]
         4,242,732 branch-misses             #    1.17% of all branches         [83.51%]

      10.128449949 seconds time elapsed

CC: Tom Herbert 
Signed-off-by: Benjamin Poirier 
Signed-off-by: David S. Miller 
Signed-off-by: Zefan Li

ipv6: reuse ip6_frag_id from ip6_ufo_append_data

2014-12-01T10:02:44+00:00

commit 916e4cf46d0204806c062c8c6c4d1f633852c5b6 upstream.

Currently we generate a new fragmentation id on UFO segmentation. It
is pretty hairy to identify the correct net namespace and dst there.
Especially tunnels use IFF_XMIT_DST_RELEASE and thus have no skb_dst
available at all.

This causes unreliable or very predictable ipv6 fragmentation id
generation while segmentation.

Luckily we already have pregenerated the ip6_frag_id in
ip6_ufo_append_data and can use it here.

Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust filename, indentation]
Signed-off-by: Ben Hutchings 
Signed-off-by: Zefan Li

ipv4: disable bh while doing route gc

2014-12-01T10:02:44+00:00

Further tests revealed that after moving the garbage collector to a work
queue and protecting it with a spinlock may leave the system prone to
soft lockups if bottom half gets very busy.

It was reproced with a set of firewall rules that REJECTed packets. If
the NIC bottom half handler ends up running on the same CPU that is
running the garbage collector on a very large cache, the garbage
collector will not be able to do its job due to the amount of work
needed for handling the REJECTs and also won't reschedule.

The fix is to disable bottom half during the garbage collecting, as it
already was in the first place (most calls to it came from softirqs).

Signed-off-by: Marcelo Ricardo Leitner 
Acked-by: Hannes Frederic Sowa 
Acked-by: David S. Miller 
Signed-off-by: Ben Hutchings 
Signed-off-by: Zefan Li

ipv4: avoid parallel route cache gc executions

2014-12-01T10:02:44+00:00

When rt_intern_hash() has to deal with neighbour cache overflowing,
it triggers the route cache garbage collector in an attempt to free
some references on neighbour entries.

Such call cannot be done async but should also not run in parallel with
an already-running one, so that they don't collapse fighting over the
hash lock entries.

This patch thus blocks parallel executions with spinlocks:
- A call from worker and from rt_intern_hash() are not the same, and
cannot be merged, thus they will wait each other on rt_gc_lock.
- Calls to gc from rt_intern_hash() may happen in parallel but we must
wait for it to finish in order to try again. This dedup and
synchrinozation is then performed by the locking just before calling
__do_rt_garbage_collect().

Signed-off-by: Marcelo Ricardo Leitner 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: Ben Hutchings 
Signed-off-by: Zefan Li

ipv4: move route garbage collector to work queue

2014-12-01T10:02:43+00:00

Currently the route garbage collector gets called by dst_alloc() if it
have more entries than the threshold. But it's an expensive call, that
don't really need to be done by then.

Another issue with current way is that it allows running the garbage
collector with the same start parameters on multiple CPUs at once, which
is not optimal. A system may even soft lockup if the cache is big enough
as the garbage collectors will be fighting over the hash lock entries.

This patch thus moves the garbage collector to run asynchronously on a
work queue, much similar to how rt_expire_check runs.

There is one condition left that allows multiple executions, which is
handled by the next patch.

Signed-off-by: Marcelo Ricardo Leitner 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: Ben Hutchings 
Signed-off-by: Zefan Li

nl80211: clear skb cb before passing to netlink

2014-12-01T10:02:41+00:00

commit bd8c78e78d5011d8111bc2533ee73b13a3bd6c42 upstream.

In testmode and vendor command reply/event SKBs we use the
skb cb data to store nl80211 parameters between allocation
and sending. This causes the code for CONFIG_NETLINK_MMAP
to get confused, because it takes ownership of the skb cb
data when the SKB is handed off to netlink, and it doesn't
explicitly clear it.

Clear the skb cb explicitly when we're done and before it
gets passed to netlink to avoid this issue.

Reported-by: Assaf Azulay 
Reported-by: David Spinadel 
Signed-off-by: Johannes Berg 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

libceph: do not hard code max auth ticket len

2014-12-01T10:02:29+00:00

commit c27a3e4d667fdcad3db7b104f75659478e0c68d8 upstream.

We hard code cephx auth ticket buffer size to 256 bytes.  This isn't
enough for any moderate setups and, in case tickets themselves are not
encrypted, leads to buffer overflows (ceph_x_decrypt() errors out, but
ceph_decode_copy() doesn't - it's just a memcpy() wrapper).  Since the
buffer is allocated dynamically anyway, allocated it a bit later, at
the point where we know how much is going to be needed.

Fixes: http://tracker.ceph.com/issues/8979

Signed-off-by: Ilya Dryomov 
Reviewed-by: Sage Weil 
Signed-off-by: Zefan Li

libceph: add process_one_ticket() helper

2014-12-01T10:02:29+00:00

commit 597cda357716a3cf8d994cb11927af917c8d71fa upstream.

Add a helper for processing individual cephx auth tickets.  Needed for
the next commit, which deals with allocating ticket buffers.  (Most of
the diff here is whitespace - view with git diff -b).

Signed-off-by: Ilya Dryomov 
Reviewed-by: Sage Weil 
Signed-off-by: Zefan Li

libceph: gracefully handle large reply messages from the mon

2014-12-01T10:02:28+00:00

commit 73c3d4812b4c755efeca0140f606f83772a39ce4 upstream.

We preallocate a few of the message types we get back from the mon.  If we
get a larger message than we are expecting, fall back to trying to allocate
a new one instead of blindly using the one we have.

Signed-off-by: Sage Weil 
Reviewed-by: Ilya Dryomov 
[lizf: Backported to 3.4: s/front_alloc_len/front_max/g]
Signed-off-by: Zefan Li