linux-stable.git/net/core, branch v4.0.8

neigh: do not modify unlinked entries

2015-07-10T16:45:34+00:00

[ Upstream commit 2c51a97f76d20ebf1f50fef908b986cb051fdff9 ]

The lockless lookups can return entry that is unlinked.
Sometimes they get reference before last neigh_cleanup_and_release,
sometimes they do not need reference. Later, any
modification attempts may result in the following problems:

1. entry is not destroyed immediately because neigh_update
can start the timer for dead entry, eg. on change to NUD_REACHABLE
state. As result, entry lives for some time but is invisible
and out of control.

2. __neigh_event_send can run in parallel with neigh_destroy
while refcnt=0 but if timer is started and expired refcnt can
reach 0 for second time leading to second neigh_destroy and
possible crash.

Thanks to Eric Dumazet and Ying Xue for their work and analyze
on the __neigh_event_send change.

Fixes: 767e97e1e0db ("neigh: RCU conversion of struct neighbour")
Fixes: a263b3093641 ("ipv4: Make neigh lookups directly in output packet path.")
Fixes: 6fd6ce2056de ("ipv6: Do not depend on rt->n in ip6_finish_output2().")
Cc: Eric Dumazet 
Cc: Ying Xue 
Signed-off-by: Julian Anastasov 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: don't wait for order-3 page allocation

2015-07-10T16:45:33+00:00

[ Upstream commit fb05e7a89f500cfc06ae277bdc911b281928995d ]

We saw excessive direct memory compaction triggered by skb_page_frag_refill.
This causes performance issues and add latency. Commit 5640f7685831e0
introduces the order-3 allocation. According to the changelog, the order-3
allocation isn't a must-have but to improve performance. But direct memory
compaction has high overhead. The benefit of order-3 allocation can't
compensate the overhead of direct memory compaction.

This patch makes the order-3 page allocation atomic. If there is no memory
pressure and memory isn't fragmented, the alloction will still success, so we
don't sacrifice the order-3 benefit here. If the atomic allocation fails,
direct memory compaction will not be triggered, skb_page_frag_refill will
fallback to order-0 immediately, hence the direct memory compaction overhead is
avoided. In the allocation failure case, kswapd is waken up and doing
compaction, so chances are allocation could success next time.

alloc_skb_with_frags is the same.

The mellanox driver does similar thing, if this is accepted, we must fix
the driver too.

V3: fix the same issue in alloc_skb_with_frags as pointed out by Eric
V2: make the changelog clearer

Cc: Eric Dumazet 
Cc: Chris Mason 
Cc: Debabrata Banerjee 
Signed-off-by: Shaohua Li 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

rtnl/bond: don't send rtnl msg for unregistered iface

2015-06-23T00:03:20+00:00

[ Upstream commit ed2a80ab7b76f11af0b2c6255709c4ebf164b667 ]

Before the patch, the command 'ip link add bond2 type bond mode 802.3ad'
causes the kernel to send a rtnl message for the bond2 interface, with an
ifindex 0.

'ip monitor' shows:
0: bond2:  mtu 1500 state DOWN group default
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
9: bond2@NONE:  mtu 1500 qdisc noop state DOWN group default
    link/ether ea:3e:1f:53:92:7b brd ff:ff:ff:ff:ff:ff
[snip]

The patch fixes the spotted bug by checking in bond driver if the interface
is registered before calling the notifier chain.
It also adds a check in rtmsg_ifinfo() to prevent this kind of bug in the
future.

Fixes: d4261e565000 ("bonding: create netlink event when bonding option is changed")
CC: Jiri Pirko 
Reported-by: Julien Meunier 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: core: Correct an over-stringent device loop detection.

2015-06-23T00:03:20+00:00

[ Upstream commit d66bf7dd27573ee5ea90484899ee952c19ccb194 ]

The code in __netdev_upper_dev_link() has an over-stringent
loop detection logic that actually prevents valid configurations
from working correctly.

In particular, the logic returns an error if an upper device
is already in the list of all upper devices for a given dev.
This particular check seems to be a overzealous as it disallows
perfectly valid configurations.  For example:
  # ip l a link eth0 name eth0.10 type vlan id 10
  # ip l a dev br0 typ bridge
  # ip l s eth0.10 master br0
  # ip l s eth0 master br0  <--- Will fail

If you switch the last two commands (add eth0 first), then both
will succeed.  If after that, you remove eth0 and try to re-add
it, it will fail!

It appears to be enough to simply check adj_list to keeps things
safe.

I've tried stacking multiple devices multiple times in all different
combinations, and either rx_handler registration prevented the stacking
of the device linking cought the error.

Signed-off-by: Vladislav Yasevich 
Acked-by: Jiri Pirko 
Acked-by: Veaceslav Falico 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: rfs: fix crash in get_rps_cpus()

2015-05-06T20:03:35+00:00

[ Upstream commit a31196b07f8034eba6a3487a1ad1bb5ec5cd58a5 ]

Commit 567e4b79731c ("net: rfs: add hash collision detection") had one
mistake :

RPS_NO_CPU is no longer the marker for invalid cpu in set_rps_cpu()
and get_rps_cpu(), as @next_cpu was the result of an AND with
rps_cpu_mask

This bug showed up on a host with 72 cpus :
next_cpu was 0x7f, and the code was trying to access percpu data of an
non existent cpu.

In a follow up patch, we might get rid of compares against nr_cpu_ids,
if we init the tables with 0. This is silly to test for a very unlikely
condition that exists only shortly after table initialization, as
we got rid of rps_reset_sock_flow() and similar functions that were
writing this RPS_NO_CPU magic value at flow dismantle : When table is
old enough, it never contains this value anymore.

Fixes: 567e4b79731c ("net: rfs: add hash collision detection")
Signed-off-by: Eric Dumazet 
Cc: Tom Herbert 
Cc: Ben Hutchings 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: fix crash in build_skb()

2015-05-06T20:03:34+00:00

[ Upstream commit 2ea2f62c8bda242433809c7f4e9eae1c52c40bbe ]

When I added pfmemalloc support in build_skb(), I forgot netlink
was using build_skb() with a vmalloc() area.

In this patch I introduce __build_skb() for netlink use,
and build_skb() is a wrapper handling both skb->head_frag and
skb->pfmemalloc

This means netlink no longer has to hack skb->head_frag

[ 1567.700067] kernel BUG at arch/x86/mm/physaddr.c:26!
[ 1567.700067] invalid opcode: 0000 [#1] PREEMPT SMP KASAN
[ 1567.700067] Dumping ftrace buffer:
[ 1567.700067]    (ftrace buffer empty)
[ 1567.700067] Modules linked in:
[ 1567.700067] CPU: 9 PID: 16186 Comm: trinity-c182 Not tainted 4.0.0-next-20150424-sasha-00037-g4796e21 #2167
[ 1567.700067] task: ffff880127efb000 ti: ffff880246770000 task.ti: ffff880246770000
[ 1567.700067] RIP: __phys_addr (arch/x86/mm/physaddr.c:26 (discriminator 3))
[ 1567.700067] RSP: 0018:ffff8802467779d8  EFLAGS: 00010202
[ 1567.700067] RAX: 000041000ed8e000 RBX: ffffc9008ed8e000 RCX: 000000000000002c
[ 1567.700067] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffffb3fd6049
[ 1567.700067] RBP: ffff8802467779f8 R08: 0000000000000019 R09: ffff8801d0168000
[ 1567.700067] R10: ffff8801d01680c7 R11: ffffed003a02d019 R12: ffffc9000ed8e000
[ 1567.700067] R13: 0000000000000f40 R14: 0000000000001180 R15: ffffc9000ed8e000
[ 1567.700067] FS:  00007f2a7da3f700(0000) GS:ffff8801d1000000(0000) knlGS:0000000000000000
[ 1567.700067] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1567.700067] CR2: 0000000000738308 CR3: 000000022e329000 CR4: 00000000000007e0
[ 1567.700067] Stack:
[ 1567.700067]  ffffc9000ed8e000 ffff8801d0168000 ffffc9000ed8e000 ffff8801d0168000
[ 1567.700067]  ffff880246777a28 ffffffffad7c0a21 0000000000001080 ffff880246777c08
[ 1567.700067]  ffff88060d302e68 ffff880246777b58 ffff880246777b88 ffffffffad9a6821
[ 1567.700067] Call Trace:
[ 1567.700067] build_skb (include/linux/mm.h:508 net/core/skbuff.c:316)
[ 1567.700067] netlink_sendmsg (net/netlink/af_netlink.c:1633 net/netlink/af_netlink.c:2329)
[ 1567.774369] ? sched_clock_cpu (kernel/sched/clock.c:311)
[ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
[ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
[ 1567.774369] sock_sendmsg (net/socket.c:614 net/socket.c:623)
[ 1567.774369] sock_write_iter (net/socket.c:823)
[ 1567.774369] ? sock_sendmsg (net/socket.c:806)
[ 1567.774369] __vfs_write (fs/read_write.c:479 fs/read_write.c:491)
[ 1567.774369] ? get_lock_stats (kernel/locking/lockdep.c:249)
[ 1567.774369] ? default_llseek (fs/read_write.c:487)
[ 1567.774369] ? vtime_account_user (kernel/sched/cputime.c:701)
[ 1567.774369] ? rw_verify_area (fs/read_write.c:406 (discriminator 4))
[ 1567.774369] vfs_write (fs/read_write.c:539)
[ 1567.774369] SyS_write (fs/read_write.c:586 fs/read_write.c:577)
[ 1567.774369] ? SyS_read (fs/read_write.c:577)
[ 1567.774369] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63)
[ 1567.774369] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2594 kernel/locking/lockdep.c:2636)
[ 1567.774369] ? trace_hardirqs_on_thunk (arch/x86/lib/thunk_64.S:42)
[ 1567.774369] system_call_fastpath (arch/x86/kernel/entry_64.S:261)

Fixes: 79930f5892e ("net: do not deplete pfmemalloc reserve")
Signed-off-by: Eric Dumazet 
Reported-by: Sasha Levin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: do not deplete pfmemalloc reserve

2015-05-06T20:03:34+00:00

[ Upstream commit 79930f5892e134c6da1254389577fffb8bd72c66 ]

build_skb() should look at the page pfmemalloc status.
If set, this means page allocator allocated this page in the
expectation it would help to free other pages. Networking
stack can do that only if skb->pfmemalloc is also set.

Also, we must refrain using high order pages from the pfmemalloc
reserve, so __page_frag_refill() must also use __GFP_NOMEMALLOC for
them. Under memory pressure, using order-0 pages is probably the best
strategy.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

skbuff: Do not scrub skb mark within the same name space

2015-04-29T08:22:18+00:00

[ Upstream commit 213dd74aee765d4e5f3f4b9607fef0cf97faa2af ]

On Wed, Apr 15, 2015 at 05:41:26PM +0200, Nicolas Dichtel wrote:
> Le 15/04/2015 15:57, Herbert Xu a écrit :
> >On Wed, Apr 15, 2015 at 06:22:29PM +0800, Herbert Xu wrote:
> [snip]
> >Subject: skbuff: Do not scrub skb mark within the same name space
> >
> >The commit ea23192e8e577dfc51e0f4fc5ca113af334edff9 ("tunnels:
> Maybe add a Fixes tag?
> Fixes: ea23192e8e57 ("tunnels: harmonize cleanup done on skb on rx path")
>
> >harmonize cleanup done on skb on rx path") broke anyone trying to
> >use netfilter marking across IPv4 tunnels.  While most of the
> >fields that are cleared by skb_scrub_packet don't matter, the
> >netfilter mark must be preserved.
> >
> >This patch rearranges skb_scurb_packet to preserve the mark field.
> nit: s/scurb/scrub
>
> Else it's fine for me.

Sure.

PS I used the wrong email for James the first time around.  So
let me repeat the question here.  Should secmark be preserved
or cleared across tunnels within the same name space? In fact,
do our security models even support name spaces?

---8<---
The commit ea23192e8e577dfc51e0f4fc5ca113af334edff9 ("tunnels:
harmonize cleanup done on skb on rx path") broke anyone trying to
use netfilter marking across IPv4 tunnels.  While most of the
fields that are cleared by skb_scrub_packet don't matter, the
netfilter mark must be preserved.

This patch rearranges skb_scrub_packet to preserve the mark field.

Fixes: ea23192e8e57 ("tunnels: harmonize cleanup done on skb on rx path")
Signed-off-by: Herbert Xu 
Acked-by: Thomas Graf 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Revert "net: Reset secmark when scrubbing packet"

2015-04-29T08:22:18+00:00

[ Upstream commit 4c0ee414e877b899f7fc80aafb98d9425c02797f ]

This patch reverts commit b8fb4e0648a2ab3734140342002f68fb0c7d1602
because the secmark must be preserved even when a packet crosses
namespace boundaries.  The reason is that security labels apply to
the system as a whole and is not per-namespace.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: protect skb->sk accesses from recursive dereference inside the stack

2015-04-06T20:12:49+00:00

We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.

ipv6 does not conform with this in three places:

1) ip6_fragment: we do consult ipv6_npinfo for frag_size

2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
   loop the packet back to the local socket

3) ip6_skb_dst_mtu could query the settings from the user socket and
   force a wrong MTU

Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.

Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.

Cc: Jiri Pirko 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller