<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/net, branch v4.5-rc4</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>vxlan, gre, geneve: Set a large MTU on ovs-created tunnel devices</title>
<updated>2016-02-10T10:50:03+00:00</updated>
<author>
<name>David Wragg</name>
<email>david@weave.works</email>
</author>
<published>2016-02-10T00:05:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7e059158d57b79159eaf1f504825d19866ef2c42'/>
<id>7e059158d57b79159eaf1f504825d19866ef2c42</id>
<content type='text'>
Prior to 4.3, openvswitch tunnel vports (vxlan, gre and geneve) could
transmit vxlan packets of any size, constrained only by the ability to
send out the resulting packets.  4.3 introduced netdevs corresponding
to tunnel vports.  These netdevs have an MTU, which limits the size of
a packet that can be successfully encapsulated.  The default MTU
values are low (1500 or less), which is awkwardly small in the context
of physical networks supporting jumbo frames, and leads to a
conspicuous change in behaviour for userspace.

Instead, set the MTU on openvswitch-created netdevs to be the relevant
maximum (i.e. the maximum IP packet size minus any relevant overhead),
effectively restoring the behaviour prior to 4.3.

Signed-off-by: David Wragg &lt;david@weave.works&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Prior to 4.3, openvswitch tunnel vports (vxlan, gre and geneve) could
transmit vxlan packets of any size, constrained only by the ability to
send out the resulting packets.  4.3 introduced netdevs corresponding
to tunnel vports.  These netdevs have an MTU, which limits the size of
a packet that can be successfully encapsulated.  The default MTU
values are low (1500 or less), which is awkwardly small in the context
of physical networks supporting jumbo frames, and leads to a
conspicuous change in behaviour for userspace.

Instead, set the MTU on openvswitch-created netdevs to be the relevant
maximum (i.e. the maximum IP packet size minus any relevant overhead),
effectively restoring the behaviour prior to 4.3.

Signed-off-by: David Wragg &lt;david@weave.works&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: do not drop syn_recv on all icmp reports</title>
<updated>2016-02-09T09:15:37+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2016-02-03T03:31:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9cf7490360bf2c46a16b7525f899e4970c5fc144'/>
<id>9cf7490360bf2c46a16b7525f899e4970c5fc144</id>
<content type='text'>
Petr Novopashenniy reported that ICMP redirects on SYN_RECV sockets
were leading to RST.

This is of course incorrect.

A specific list of ICMP messages should be able to drop a SYN_RECV.

For instance, a REDIRECT on SYN_RECV shall be ignored, as we do
not hold a dst per SYN_RECV pseudo request.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=111751
Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Reported-by: Petr Novopashenniy &lt;pety@rusnet.ru&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Petr Novopashenniy reported that ICMP redirects on SYN_RECV sockets
were leading to RST.

This is of course incorrect.

A specific list of ICMP messages should be able to drop a SYN_RECV.

For instance, a REDIRECT on SYN_RECV shall be ignored, as we do
not hold a dst per SYN_RECV pseudo request.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=111751
Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Reported-by: Petr Novopashenniy &lt;pety@rusnet.ru&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>unix: correctly track in-flight fds in sending process user_struct</title>
<updated>2016-02-08T15:30:42+00:00</updated>
<author>
<name>Hannes Frederic Sowa</name>
<email>hannes@stressinduktion.org</email>
</author>
<published>2016-02-03T01:11:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=415e3d3e90ce9e18727e8843ae343eda5a58fad6'/>
<id>415e3d3e90ce9e18727e8843ae343eda5a58fad6</id>
<content type='text'>
The commit referenced in the Fixes tag incorrectly accounted the number
of in-flight fds over a unix domain socket to the original opener
of the file-descriptor. This allows another process to arbitrary
deplete the original file-openers resource limit for the maximum of
open files. Instead the sending processes and its struct cred should
be credited.

To do so, we add a reference counted struct user_struct pointer to the
scm_fp_list and use it to account for the number of inflight unix fds.

Fixes: 712f4aad406bb1 ("unix: properly account for FDs passed over unix sockets")
Reported-by: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Cc: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Cc: Willy Tarreau &lt;w@1wt.eu&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The commit referenced in the Fixes tag incorrectly accounted the number
of in-flight fds over a unix domain socket to the original opener
of the file-descriptor. This allows another process to arbitrary
deplete the original file-openers resource limit for the maximum of
open files. Instead the sending processes and its struct cred should
be credited.

To do so, we add a reference counted struct user_struct pointer to the
scm_fp_list and use it to account for the number of inflight unix fds.

Fixes: 712f4aad406bb1 ("unix: properly account for FDs passed over unix sockets")
Reported-by: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Cc: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Cc: Willy Tarreau &lt;w@1wt.eu&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</title>
<updated>2016-02-01T23:56:08+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-02-01T23:56:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=34229b277480f46c1e9a19f027f30b074512e68b'/>
<id>34229b277480f46c1e9a19f027f30b074512e68b</id>
<content type='text'>
Pull networking fixes from David Miller:
 "This looks like a lot but it's a mixture of regression fixes as well
  as fixes for longer standing issues.

   1) Fix on-channel cancellation in mac80211, from Johannes Berg.

   2) Handle CHECKSUM_COMPLETE properly in xt_TCPMSS netfilter xtables
      module, from Eric Dumazet.

   3) Avoid infinite loop in UDP SO_REUSEPORT logic, also from Eric
      Dumazet.

   4) Avoid a NULL deref if we try to set SO_REUSEPORT after a socket is
      bound, from Craig Gallek.

   5) GRO key comparisons don't take lightweight tunnels into account,
      from Jesse Gross.

   6) Fix struct pid leak via SCM credentials in AF_UNIX, from Eric
      Dumazet.

   7) We need to set the rtnl_link_ops of ipv6 SIT tunnels before we
      register them, otherwise the NEWLINK netlink message is missing
      the proper attributes.  From Thadeu Lima de Souza Cascardo.

   8) Several Spectrum chip bug fixes for mlxsw switch driver, from Ido
      Schimmel

   9) Handle fragments properly in ipv4 easly socket demux, from Eric
      Dumazet.

  10) Don't ignore the ifindex key specifier on ipv6 output route
      lookups, from Paolo Abeni"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (128 commits)
  tcp: avoid cwnd undo after receiving ECN
  irda: fix a potential use-after-free in ircomm_param_request
  net: tg3: avoid uninitialized variable warning
  net: nb8800: avoid uninitialized variable warning
  net: vxge: avoid unused function warnings
  net: bgmac: clarify CONFIG_BCMA dependency
  net: hp100: remove unnecessary #ifdefs
  net: davinci_cpdma: use dma_addr_t for DMA address
  ipv6/udp: use sticky pktinfo egress ifindex on connect()
  ipv6: enforce flowi6_oif usage in ip6_dst_lookup_tail()
  netlink: not trim skb for mmaped socket when dump
  vxlan: fix a out of bounds access in __vxlan_find_mac
  net: dsa: mv88e6xxx: fix port VLAN maps
  fib_trie: Fix shift by 32 in fib_table_lookup
  net: moxart: use correct accessors for DMA memory
  ipv4: ipconfig: avoid unused ic_proto_used symbol
  bnxt_en: Fix crash in bnxt_free_tx_skbs() during tx timeout.
  bnxt_en: Exclude rx_drop_pkts hw counter from the stack's rx_dropped counter.
  bnxt_en: Ring free response from close path should use completion ring
  net_sched: drr: check for NULL pointer in drr_dequeue
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:
 "This looks like a lot but it's a mixture of regression fixes as well
  as fixes for longer standing issues.

   1) Fix on-channel cancellation in mac80211, from Johannes Berg.

   2) Handle CHECKSUM_COMPLETE properly in xt_TCPMSS netfilter xtables
      module, from Eric Dumazet.

   3) Avoid infinite loop in UDP SO_REUSEPORT logic, also from Eric
      Dumazet.

   4) Avoid a NULL deref if we try to set SO_REUSEPORT after a socket is
      bound, from Craig Gallek.

   5) GRO key comparisons don't take lightweight tunnels into account,
      from Jesse Gross.

   6) Fix struct pid leak via SCM credentials in AF_UNIX, from Eric
      Dumazet.

   7) We need to set the rtnl_link_ops of ipv6 SIT tunnels before we
      register them, otherwise the NEWLINK netlink message is missing
      the proper attributes.  From Thadeu Lima de Souza Cascardo.

   8) Several Spectrum chip bug fixes for mlxsw switch driver, from Ido
      Schimmel

   9) Handle fragments properly in ipv4 easly socket demux, from Eric
      Dumazet.

  10) Don't ignore the ifindex key specifier on ipv6 output route
      lookups, from Paolo Abeni"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (128 commits)
  tcp: avoid cwnd undo after receiving ECN
  irda: fix a potential use-after-free in ircomm_param_request
  net: tg3: avoid uninitialized variable warning
  net: nb8800: avoid uninitialized variable warning
  net: vxge: avoid unused function warnings
  net: bgmac: clarify CONFIG_BCMA dependency
  net: hp100: remove unnecessary #ifdefs
  net: davinci_cpdma: use dma_addr_t for DMA address
  ipv6/udp: use sticky pktinfo egress ifindex on connect()
  ipv6: enforce flowi6_oif usage in ip6_dst_lookup_tail()
  netlink: not trim skb for mmaped socket when dump
  vxlan: fix a out of bounds access in __vxlan_find_mac
  net: dsa: mv88e6xxx: fix port VLAN maps
  fib_trie: Fix shift by 32 in fib_table_lookup
  net: moxart: use correct accessors for DMA memory
  ipv4: ipconfig: avoid unused ic_proto_used symbol
  bnxt_en: Fix crash in bnxt_free_tx_skbs() during tx timeout.
  bnxt_en: Exclude rx_drop_pkts hw counter from the stack's rx_dropped counter.
  bnxt_en: Ring free response from close path should use completion ring
  net_sched: drr: check for NULL pointer in drr_dequeue
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth</title>
<updated>2016-01-30T23:32:42+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2016-01-30T23:32:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=53729eb174c1589f9185340ffe8c10b3f39f3ef3'/>
<id>53729eb174c1589f9185340ffe8c10b3f39f3ef3</id>
<content type='text'>
Johan Hedberg says:

====================
pull request: bluetooth 2016-01-30

Here's a set of important Bluetooth fixes for the 4.5 kernel:

 - Two fixes to 6LoWPAN code (one fixing a potential crash)
 - Fix LE pairing with devices using both public and random addresses
 - Fix allocation of dynamic LE PSM values
 - Fix missing COMPATIBLE_IOCTL for UART line discipline

Please let me know if there are any issues pulling. Thanks.
====================

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Johan Hedberg says:

====================
pull request: bluetooth 2016-01-30

Here's a set of important Bluetooth fixes for the 4.5 kernel:

 - Two fixes to 6LoWPAN code (one fixing a potential crash)
 - Fix LE pairing with devices using both public and random addresses
 - Fix allocation of dynamic LE PSM values
 - Fix missing COMPATIBLE_IOCTL for UART line discipline

Please let me know if there are any issues pulling. Thanks.
====================

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ipv6: enforce flowi6_oif usage in ip6_dst_lookup_tail()</title>
<updated>2016-01-30T04:31:26+00:00</updated>
<author>
<name>Paolo Abeni</name>
<email>pabeni@redhat.com</email>
</author>
<published>2016-01-29T11:30:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6f21c96a78b835259546d8f3fb4edff0f651d478'/>
<id>6f21c96a78b835259546d8f3fb4edff0f651d478</id>
<content type='text'>
The current implementation of ip6_dst_lookup_tail basically
ignore the egress ifindex match: if the saddr is set,
ip6_route_output() purposefully ignores flowi6_oif, due
to the commit d46a9d678e4c ("net: ipv6: Dont add RT6_LOOKUP_F_IFACE
flag if saddr set"), if the saddr is 'any' the first route lookup
in ip6_dst_lookup_tail fails, but upon failure a second lookup will
be performed with saddr set, thus ignoring the ifindex constraint.

This commit adds an output route lookup function variant, which
allows the caller to specify lookup flags, and modify
ip6_dst_lookup_tail() to enforce the ifindex match on the second
lookup via said helper.

ip6_route_output() becames now a static inline function build on
top of ip6_route_output_flags(); as a side effect, out-of-tree
modules need now a GPL license to access the output route lookup
functionality.

Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Acked-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Acked-by: David Ahern &lt;dsa@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The current implementation of ip6_dst_lookup_tail basically
ignore the egress ifindex match: if the saddr is set,
ip6_route_output() purposefully ignores flowi6_oif, due
to the commit d46a9d678e4c ("net: ipv6: Dont add RT6_LOOKUP_F_IFACE
flag if saddr set"), if the saddr is 'any' the first route lookup
in ip6_dst_lookup_tail fails, but upon failure a second lookup will
be performed with saddr set, thus ignoring the ifindex constraint.

This commit adds an output route lookup function variant, which
allows the caller to specify lookup flags, and modify
ip6_dst_lookup_tail() to enforce the ifindex match on the second
lookup via said helper.

ip6_route_output() becames now a static inline function build on
top of ip6_route_output_flags(); as a side effect, out-of-tree
modules need now a GPL license to access the output route lookup
functionality.

Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Acked-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Acked-by: David Ahern &lt;dsa@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: Change reference to experimental CWND RFC.</title>
<updated>2016-01-29T20:23:58+00:00</updated>
<author>
<name>Jörg Thalheim</name>
<email>joerg@higgsboson.tk</email>
</author>
<published>2016-01-27T21:54:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=21603fc45bdef3696f45d80a1c9d730e06b925c5'/>
<id>21603fc45bdef3696f45d80a1c9d730e06b925c5</id>
<content type='text'>
Signed-off-by: Jörg Thalheim &lt;joerg@higgsboson.tk&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Jörg Thalheim &lt;joerg@higgsboson.tk&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: L2CAP: Introduce proper defines for PSM ranges</title>
<updated>2016-01-29T10:47:24+00:00</updated>
<author>
<name>Johan Hedberg</name>
<email>johan.hedberg@intel.com</email>
</author>
<published>2016-01-26T22:19:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=114f9f1e038eb23935c20fb54f49f07caaa0546d'/>
<id>114f9f1e038eb23935c20fb54f49f07caaa0546d</id>
<content type='text'>
Having proper defines makes the code a bit readable, it also avoids
duplicating hard-coded values since these are also needed when
auto-allocating PSM values (in a subsequent patch).

Signed-off-by: Johan Hedberg &lt;johan.hedberg@intel.com&gt;
Signed-off-by: Marcel Holtmann &lt;marcel@holtmann.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Having proper defines makes the code a bit readable, it also avoids
duplicating hard-coded values since these are also needed when
auto-allocating PSM values (in a subsequent patch).

Signed-off-by: Johan Hedberg &lt;johan.hedberg@intel.com&gt;
Signed-off-by: Marcel Holtmann &lt;marcel@holtmann.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sctp: remove the dead field of sctp_transport</title>
<updated>2016-01-28T23:59:32+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2016-01-21T17:49:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=47faa1e4c50ec26e6e75dcd1ce53f064bd45f729'/>
<id>47faa1e4c50ec26e6e75dcd1ce53f064bd45f729</id>
<content type='text'>
After we use refcnt to check if transport is alive, the dead can be
removed from sctp_transport.

The traversal of transport_addr_list in procfs dump is using
list_for_each_entry_rcu, no need to check if it has been freed.

sctp_generate_t3_rtx_event and sctp_generate_heartbeat_event is
protected by sock lock, it's not necessary to check dead, either.
also, the timers are cancelled when sctp_transport_free() is
called, that it doesn't wait for refcnt to reach 0 to cancel them.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After we use refcnt to check if transport is alive, the dead can be
removed from sctp_transport.

The traversal of transport_addr_list in procfs dump is using
list_for_each_entry_rcu, no need to check if it has been freed.

sctp_generate_t3_rtx_event and sctp_generate_heartbeat_event is
protected by sock lock, it's not necessary to check dead, either.
also, the timers are cancelled when sctp_transport_free() is
called, that it doesn't wait for refcnt to reach 0 to cancel them.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sctp: fix the transport dead race check by using atomic_add_unless on refcnt</title>
<updated>2016-01-28T23:59:32+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2016-01-21T17:49:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1eed677933b816978abc4e3e18ecae5f254cb9be'/>
<id>1eed677933b816978abc4e3e18ecae5f254cb9be</id>
<content type='text'>
Now when __sctp_lookup_association is running in BH, it will try to
check if t-&gt;dead is set, but meanwhile other CPUs may be freeing this
transport and this assoc and if it happens that
__sctp_lookup_association checked t-&gt;dead a bit too early, it may think
that the association is still good while it was already freed.

So we fix this race by using atomic_add_unless in sctp_transport_hold.
After we get one transport from hashtable, we will hold it only when
this transport's refcnt is not 0, so that we can make sure t-&gt;asoc
cannot be freed before we hold the asoc again.

Note that sctp association is not freed using RCU so we can't use
atomic_add_unless() with it as it may just be too late for that either.

Fixes: 4f0087812648 ("sctp: apply rhashtable api to send/recv path")
Reported-by: Vlad Yasevich &lt;vyasevich@gmail.com&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
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Now when __sctp_lookup_association is running in BH, it will try to
check if t-&gt;dead is set, but meanwhile other CPUs may be freeing this
transport and this assoc and if it happens that
__sctp_lookup_association checked t-&gt;dead a bit too early, it may think
that the association is still good while it was already freed.

So we fix this race by using atomic_add_unless in sctp_transport_hold.
After we get one transport from hashtable, we will hold it only when
this transport's refcnt is not 0, so that we can make sure t-&gt;asoc
cannot be freed before we hold the asoc again.

Note that sctp association is not freed using RCU so we can't use
atomic_add_unless() with it as it may just be too late for that either.

Fixes: 4f0087812648 ("sctp: apply rhashtable api to send/recv path")
Reported-by: Vlad Yasevich &lt;vyasevich@gmail.com&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
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