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<title>linux-toradex.git/net/sctp/input.c, branch v4.9.91</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>sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect</title>
<updated>2017-11-18T10:22:21+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2017-10-18T13:37:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bcb9ced1833c4cafb425077d8114d9d23de0ef95'/>
<id>bcb9ced1833c4cafb425077d8114d9d23de0ef95</id>
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[ Upstream commit 1cc276cec9ec574d41cf47dfc0f51406b6f26ab4 ]

Now sctp processes icmp redirect packet in sctp_icmp_redirect where
it calls sctp_transport_dst_check in which tp-&gt;dst can be released.

The problem is before calling sctp_transport_dst_check, it doesn't
check sock_owned_by_user, which means tp-&gt;dst could be freed while
a process is accessing it with owning the socket.

An use-after-free issue could be triggered by this.

This patch is to fix it by checking sock_owned_by_user before calling
sctp_transport_dst_check in sctp_icmp_redirect, so that it would not
release tp-&gt;dst if users still hold sock lock.

Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix
routing redirect race") on sctp also needs this check.

Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers")
Reported-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Acked-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
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<pre>
[ Upstream commit 1cc276cec9ec574d41cf47dfc0f51406b6f26ab4 ]

Now sctp processes icmp redirect packet in sctp_icmp_redirect where
it calls sctp_transport_dst_check in which tp-&gt;dst can be released.

The problem is before calling sctp_transport_dst_check, it doesn't
check sock_owned_by_user, which means tp-&gt;dst could be freed while
a process is accessing it with owning the socket.

An use-after-free issue could be triggered by this.

This patch is to fix it by checking sock_owned_by_user before calling
sctp_transport_dst_check in sctp_icmp_redirect, so that it would not
release tp-&gt;dst if users still hold sock lock.

Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix
routing redirect race") on sctp also needs this check.

Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers")
Reported-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Acked-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sctp: fix ICMP processing if skb is non-linear</title>
<updated>2017-06-07T10:07:45+00:00</updated>
<author>
<name>Davide Caratti</name>
<email>dcaratti@redhat.com</email>
</author>
<published>2017-05-25T17:14:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1de51502a02598a8deaced6ab7575089108ec823'/>
<id>1de51502a02598a8deaced6ab7575089108ec823</id>
<content type='text'>
[ Upstream commit 804ec7ebe8ea003999ca8d1bfc499edc6a9e07df ]

sometimes ICMP replies to INIT chunks are ignored by the client, even if
the encapsulated SCTP headers match an open socket. This happens when the
ICMP packet is carried by a paged skb: use skb_header_pointer() to read
packet contents beyond the SCTP header, so that chunk header and initiate
tag are validated correctly.

v2:
- don't use skb_header_pointer() to read the transport header, since
  icmp_socket_deliver() already puts these 8 bytes in the linear area.
- change commit message to make specific reference to INIT chunks.

Signed-off-by: Davide Caratti &lt;dcaratti@redhat.com&gt;
Acked-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Acked-by: Vlad Yasevich &lt;vyasevich@gmail.com&gt;
Reviewed-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 804ec7ebe8ea003999ca8d1bfc499edc6a9e07df ]

sometimes ICMP replies to INIT chunks are ignored by the client, even if
the encapsulated SCTP headers match an open socket. This happens when the
ICMP packet is carried by a paged skb: use skb_header_pointer() to read
packet contents beyond the SCTP header, so that chunk header and initiate
tag are validated correctly.

v2:
- don't use skb_header_pointer() to read the transport header, since
  icmp_socket_deliver() already puts these 8 bytes in the linear area.
- change commit message to make specific reference to INIT chunks.

Signed-off-by: Davide Caratti &lt;dcaratti@redhat.com&gt;
Acked-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Acked-by: Vlad Yasevich &lt;vyasevich@gmail.com&gt;
Reviewed-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sctp: hold transport instead of assoc when lookup assoc in rx path</title>
<updated>2016-10-31T20:20:33+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2016-10-31T12:32:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=dae399d7fdee84d8f5227a9711d95bb4e9a05d4e'/>
<id>dae399d7fdee84d8f5227a9711d95bb4e9a05d4e</id>
<content type='text'>
Prior to this patch, in rx path, before calling lock_sock, it needed to
hold assoc when got it by __sctp_lookup_association, in case other place
would free/put assoc.

But in __sctp_lookup_association, it lookup and hold transport, then got
assoc by transport-&gt;assoc, then hold assoc and put transport. It means
it didn't hold transport, yet it was returned and later on directly
assigned to chunk-&gt;transport.

Without the protection of sock lock, the transport may be freed/put by
other places, which would cause a use-after-free issue.

This patch is to fix this issue by holding transport instead of assoc.
As holding transport can make sure to access assoc is also safe, and
actually it looks up assoc by searching transport rhashtable, to hold
transport here makes more sense.

Note that the function will be renamed later on on another patch.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
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<pre>
Prior to this patch, in rx path, before calling lock_sock, it needed to
hold assoc when got it by __sctp_lookup_association, in case other place
would free/put assoc.

But in __sctp_lookup_association, it lookup and hold transport, then got
assoc by transport-&gt;assoc, then hold assoc and put transport. It means
it didn't hold transport, yet it was returned and later on directly
assigned to chunk-&gt;transport.

Without the protection of sock lock, the transport may be freed/put by
other places, which would cause a use-after-free issue.

This patch is to fix this issue by holding transport instead of assoc.
As holding transport can make sure to access assoc is also safe, and
actually it looks up assoc by searching transport rhashtable, to hold
transport here makes more sense.

Note that the function will be renamed later on on another patch.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-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: return back transport in __sctp_rcv_init_lookup</title>
<updated>2016-10-31T20:20:32+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2016-10-31T12:32:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7c17fcc726903ffed1716351efdc617e752533ed'/>
<id>7c17fcc726903ffed1716351efdc617e752533ed</id>
<content type='text'>
Prior to this patch, it used a local variable to save the transport that is
looked up by __sctp_lookup_association(), and didn't return it back. But in
sctp_rcv, it is used to initialize chunk-&gt;transport. So when hitting this,
even if it found the transport, it was still initializing chunk-&gt;transport
with null instead.

This patch is to return the transport back through transport pointer
that is from __sctp_rcv_lookup_harder().

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
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<pre>
Prior to this patch, it used a local variable to save the transport that is
looked up by __sctp_lookup_association(), and didn't return it back. But in
sctp_rcv, it is used to initialize chunk-&gt;transport. So when hitting this,
even if it found the transport, it was still initializing chunk-&gt;transport
with null instead.

This patch is to return the transport back through transport pointer
that is from __sctp_rcv_lookup_harder().

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-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>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</title>
<updated>2016-09-23T10:46:57+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2016-09-23T10:46:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d6989d4bbe6c4d1c2a76696833a07f044e85694d'/>
<id>d6989d4bbe6c4d1c2a76696833a07f044e85694d</id>
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</content>
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<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>sctp: rename WORD_TRUNC/ROUND macros</title>
<updated>2016-09-22T07:13:26+00:00</updated>
<author>
<name>Marcelo Ricardo Leitner</name>
<email>marcelo.leitner@gmail.com</email>
</author>
<published>2016-09-21T11:45:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e2f036a97271cf5811ee754bf321a29a814577f9'/>
<id>e2f036a97271cf5811ee754bf321a29a814577f9</id>
<content type='text'>
To something more meaningful these days, specially because this is
working on packet headers or lengths and which are not tied to any CPU
arch but to the protocol itself.

So, WORD_TRUNC becomes SCTP_TRUNC4 and WORD_ROUND becomes SCTP_PAD4.

Reported-by: David Laight &lt;David.Laight@ACULAB.COM&gt;
Reported-by: David Miller &lt;davem@davemloft.net&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>
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<pre>
To something more meaningful these days, specially because this is
working on packet headers or lengths and which are not tied to any CPU
arch but to the protocol itself.

So, WORD_TRUNC becomes SCTP_TRUNC4 and WORD_ROUND becomes SCTP_PAD4.

Reported-by: David Laight &lt;David.Laight@ACULAB.COM&gt;
Reported-by: David Miller &lt;davem@davemloft.net&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: hold the transport before using it in sctp_hash_cmp</title>
<updated>2016-09-13T15:44:58+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2016-09-10T15:11:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=715f5552b1e90ba3eecf6d1a6d044d0d5226663f'/>
<id>715f5552b1e90ba3eecf6d1a6d044d0d5226663f</id>
<content type='text'>
Since commit 4f0087812648 ("sctp: apply rhashtable api to send/recv
path"), sctp uses transport rhashtable with .obj_cmpfn sctp_hash_cmp,
in which it compares the members of the transport with the rhashtable
args to check if it's the right transport.

But sctp uses the transport without holding it in sctp_hash_cmp, it can
cause a use-after-free panic. As after it gets transport from hashtable,
another CPU may close the sk and free the asoc. In sctp_association_free,
it frees all the transports, meanwhile, the assoc's refcnt may be reduced
to 0, assoc can be destroyed by sctp_association_destroy.

So after that, transport-&gt;assoc is actually an unavailable memory address
in sctp_hash_cmp. Although sctp_hash_cmp is under rcu_read_lock, it still
can not avoid this, as assoc is not freed by RCU.

This patch is to hold the transport before checking it's members with
sctp_transport_hold, in which it checks the refcnt first, holds it if
it's not 0.

Fixes: 4f0087812648 ("sctp: apply rhashtable api to send/recv path")
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-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>
Since commit 4f0087812648 ("sctp: apply rhashtable api to send/recv
path"), sctp uses transport rhashtable with .obj_cmpfn sctp_hash_cmp,
in which it compares the members of the transport with the rhashtable
args to check if it's the right transport.

But sctp uses the transport without holding it in sctp_hash_cmp, it can
cause a use-after-free panic. As after it gets transport from hashtable,
another CPU may close the sk and free the asoc. In sctp_association_free,
it frees all the transports, meanwhile, the assoc's refcnt may be reduced
to 0, assoc can be destroyed by sctp_association_destroy.

So after that, transport-&gt;assoc is actually an unavailable memory address
in sctp_hash_cmp. Although sctp_hash_cmp is under rcu_read_lock, it still
can not avoid this, as assoc is not freed by RCU.

This patch is to hold the transport before checking it's members with
sctp_transport_hold, in which it checks the refcnt first, holds it if
it's not 0.

Fixes: 4f0087812648 ("sctp: apply rhashtable api to send/recv path")
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-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: linearize early if it's not GSO</title>
<updated>2016-08-20T00:09:42+00:00</updated>
<author>
<name>Marcelo Ricardo Leitner</name>
<email>marcelo.leitner@gmail.com</email>
</author>
<published>2016-08-18T17:58:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4c2f2454964477c66ef57745daab203b71783f66'/>
<id>4c2f2454964477c66ef57745daab203b71783f66</id>
<content type='text'>
Because otherwise when crc computation is still needed it's way more
expensive than on a linear buffer to the point that it affects
performance.

It's so expensive that netperf test gives a perf output as below:

Overhead  Command         Shared Object       Symbol
  18,62%  netserver       [kernel.vmlinux]    [k] crc32_generic_shift
   2,57%  netserver       [kernel.vmlinux]    [k] __pskb_pull_tail
   1,94%  netserver       [kernel.vmlinux]    [k] fib_table_lookup
   1,90%  netserver       [kernel.vmlinux]    [k] copy_user_enhanced_fast_string
   1,66%  swapper         [kernel.vmlinux]    [k] intel_idle
   1,63%  netserver       [kernel.vmlinux]    [k] _raw_spin_lock
   1,59%  netserver       [sctp]              [k] sctp_packet_transmit
   1,55%  netserver       [kernel.vmlinux]    [k] memcpy_erms
   1,42%  netserver       [sctp]              [k] sctp_rcv

# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () 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      % S      us/KB   us/KB

212992 212992  12000    10.00      3016.42   2.88     3.78     1.874   2.462

After patch:
Overhead  Command         Shared Object      Symbol
   2,75%  netserver       [kernel.vmlinux]   [k] memcpy_erms
   2,63%  netserver       [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
   2,39%  netserver       [kernel.vmlinux]   [k] fib_table_lookup
   2,04%  netserver       [kernel.vmlinux]   [k] __pskb_pull_tail
   1,91%  netserver       [kernel.vmlinux]   [k] _raw_spin_lock
   1,91%  netserver       [sctp]             [k] sctp_packet_transmit
   1,72%  netserver       [mlx4_en]          [k] mlx4_en_process_rx_cq
   1,68%  netserver       [sctp]             [k] sctp_rcv

# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () 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      % S      us/KB   us/KB

212992 212992  12000    10.00      3681.77   3.83     3.46     2.045   1.849

Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
Signed-off-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Because otherwise when crc computation is still needed it's way more
expensive than on a linear buffer to the point that it affects
performance.

It's so expensive that netperf test gives a perf output as below:

Overhead  Command         Shared Object       Symbol
  18,62%  netserver       [kernel.vmlinux]    [k] crc32_generic_shift
   2,57%  netserver       [kernel.vmlinux]    [k] __pskb_pull_tail
   1,94%  netserver       [kernel.vmlinux]    [k] fib_table_lookup
   1,90%  netserver       [kernel.vmlinux]    [k] copy_user_enhanced_fast_string
   1,66%  swapper         [kernel.vmlinux]    [k] intel_idle
   1,63%  netserver       [kernel.vmlinux]    [k] _raw_spin_lock
   1,59%  netserver       [sctp]              [k] sctp_packet_transmit
   1,55%  netserver       [kernel.vmlinux]    [k] memcpy_erms
   1,42%  netserver       [sctp]              [k] sctp_rcv

# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () 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      % S      us/KB   us/KB

212992 212992  12000    10.00      3016.42   2.88     3.78     1.874   2.462

After patch:
Overhead  Command         Shared Object      Symbol
   2,75%  netserver       [kernel.vmlinux]   [k] memcpy_erms
   2,63%  netserver       [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
   2,39%  netserver       [kernel.vmlinux]   [k] fib_table_lookup
   2,04%  netserver       [kernel.vmlinux]   [k] __pskb_pull_tail
   1,91%  netserver       [kernel.vmlinux]   [k] _raw_spin_lock
   1,91%  netserver       [sctp]             [k] sctp_packet_transmit
   1,72%  netserver       [mlx4_en]          [k] mlx4_en_process_rx_cq
   1,68%  netserver       [sctp]             [k] sctp_rcv

# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () 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      % S      us/KB   us/KB

212992 212992  12000    10.00      3681.77   3.83     3.46     2.045   1.849

Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
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 BH handling on socket backlog</title>
<updated>2016-07-25T18:22:22+00:00</updated>
<author>
<name>Marcelo Ricardo Leitner</name>
<email>marcelo.leitner@gmail.com</email>
</author>
<published>2016-07-23T03:32:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=eefc1b1d105ee4d2ce907833ce675f1e9599b5e3'/>
<id>eefc1b1d105ee4d2ce907833ce675f1e9599b5e3</id>
<content type='text'>
Now that the backlog processing is called with BH enabled, we have to
disable BH before taking the socket lock via bh_lock_sock() otherwise
it may dead lock:

sctp_backlog_rcv()
                bh_lock_sock(sk);

                if (sock_owned_by_user(sk)) {
                        if (sk_add_backlog(sk, skb, sk-&gt;sk_rcvbuf))
                                sctp_chunk_free(chunk);
                        else
                                backloged = 1;
                } else
                        sctp_inq_push(inqueue, chunk);

                bh_unlock_sock(sk);

while sctp_inq_push() was disabling/enabling BH, but enabling BH
triggers pending softirq, which then may try to re-lock the socket in
sctp_rcv().

[  219.187215]  &lt;IRQ&gt;
[  219.187217]  [&lt;ffffffff817ca3e0&gt;] _raw_spin_lock+0x20/0x30
[  219.187223]  [&lt;ffffffffa041888c&gt;] sctp_rcv+0x48c/0xba0 [sctp]
[  219.187225]  [&lt;ffffffff816e7db2&gt;] ? nf_iterate+0x62/0x80
[  219.187226]  [&lt;ffffffff816f1b14&gt;] ip_local_deliver_finish+0x94/0x1e0
[  219.187228]  [&lt;ffffffff816f1e1f&gt;] ip_local_deliver+0x6f/0xf0
[  219.187229]  [&lt;ffffffff816f1a80&gt;] ? ip_rcv_finish+0x3b0/0x3b0
[  219.187230]  [&lt;ffffffff816f17a8&gt;] ip_rcv_finish+0xd8/0x3b0
[  219.187232]  [&lt;ffffffff816f2122&gt;] ip_rcv+0x282/0x3a0
[  219.187233]  [&lt;ffffffff810d8bb6&gt;] ? update_curr+0x66/0x180
[  219.187235]  [&lt;ffffffff816abac4&gt;] __netif_receive_skb_core+0x524/0xa90
[  219.187236]  [&lt;ffffffff810d8e00&gt;] ? update_cfs_shares+0x30/0xf0
[  219.187237]  [&lt;ffffffff810d557c&gt;] ? __enqueue_entity+0x6c/0x70
[  219.187239]  [&lt;ffffffff810dc454&gt;] ? enqueue_entity+0x204/0xdf0
[  219.187240]  [&lt;ffffffff816ac048&gt;] __netif_receive_skb+0x18/0x60
[  219.187242]  [&lt;ffffffff816ad1ce&gt;] process_backlog+0x9e/0x140
[  219.187243]  [&lt;ffffffff816ac8ec&gt;] net_rx_action+0x22c/0x370
[  219.187245]  [&lt;ffffffff817cd352&gt;] __do_softirq+0x112/0x2e7
[  219.187247]  [&lt;ffffffff817cc3bc&gt;] do_softirq_own_stack+0x1c/0x30
[  219.187247]  &lt;EOI&gt;
[  219.187248]  [&lt;ffffffff810aa1c8&gt;] do_softirq.part.14+0x38/0x40
[  219.187249]  [&lt;ffffffff810aa24d&gt;] __local_bh_enable_ip+0x7d/0x80
[  219.187254]  [&lt;ffffffffa0408428&gt;] sctp_inq_push+0x68/0x80 [sctp]
[  219.187258]  [&lt;ffffffffa04190f1&gt;] sctp_backlog_rcv+0x151/0x1c0 [sctp]
[  219.187260]  [&lt;ffffffff81692b07&gt;] __release_sock+0x87/0xf0
[  219.187261]  [&lt;ffffffff81692ba0&gt;] release_sock+0x30/0xa0
[  219.187265]  [&lt;ffffffffa040e46d&gt;] sctp_accept+0x17d/0x210 [sctp]
[  219.187266]  [&lt;ffffffff810e7510&gt;] ? prepare_to_wait_event+0xf0/0xf0
[  219.187268]  [&lt;ffffffff8172d52c&gt;] inet_accept+0x3c/0x130
[  219.187269]  [&lt;ffffffff8168d7a3&gt;] SYSC_accept4+0x103/0x210
[  219.187271]  [&lt;ffffffff817ca2ba&gt;] ? _raw_spin_unlock_bh+0x1a/0x20
[  219.187272]  [&lt;ffffffff81692bfc&gt;] ? release_sock+0x8c/0xa0
[  219.187276]  [&lt;ffffffffa0413e22&gt;] ? sctp_inet_listen+0x62/0x1b0 [sctp]
[  219.187277]  [&lt;ffffffff8168f2d0&gt;] SyS_accept+0x10/0x20

Fixes: 860fbbc343bf ("sctp: prepare for socket backlog behavior change")
Cc: Eric Dumazet &lt;eric.dumazet@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>
Now that the backlog processing is called with BH enabled, we have to
disable BH before taking the socket lock via bh_lock_sock() otherwise
it may dead lock:

sctp_backlog_rcv()
                bh_lock_sock(sk);

                if (sock_owned_by_user(sk)) {
                        if (sk_add_backlog(sk, skb, sk-&gt;sk_rcvbuf))
                                sctp_chunk_free(chunk);
                        else
                                backloged = 1;
                } else
                        sctp_inq_push(inqueue, chunk);

                bh_unlock_sock(sk);

while sctp_inq_push() was disabling/enabling BH, but enabling BH
triggers pending softirq, which then may try to re-lock the socket in
sctp_rcv().

[  219.187215]  &lt;IRQ&gt;
[  219.187217]  [&lt;ffffffff817ca3e0&gt;] _raw_spin_lock+0x20/0x30
[  219.187223]  [&lt;ffffffffa041888c&gt;] sctp_rcv+0x48c/0xba0 [sctp]
[  219.187225]  [&lt;ffffffff816e7db2&gt;] ? nf_iterate+0x62/0x80
[  219.187226]  [&lt;ffffffff816f1b14&gt;] ip_local_deliver_finish+0x94/0x1e0
[  219.187228]  [&lt;ffffffff816f1e1f&gt;] ip_local_deliver+0x6f/0xf0
[  219.187229]  [&lt;ffffffff816f1a80&gt;] ? ip_rcv_finish+0x3b0/0x3b0
[  219.187230]  [&lt;ffffffff816f17a8&gt;] ip_rcv_finish+0xd8/0x3b0
[  219.187232]  [&lt;ffffffff816f2122&gt;] ip_rcv+0x282/0x3a0
[  219.187233]  [&lt;ffffffff810d8bb6&gt;] ? update_curr+0x66/0x180
[  219.187235]  [&lt;ffffffff816abac4&gt;] __netif_receive_skb_core+0x524/0xa90
[  219.187236]  [&lt;ffffffff810d8e00&gt;] ? update_cfs_shares+0x30/0xf0
[  219.187237]  [&lt;ffffffff810d557c&gt;] ? __enqueue_entity+0x6c/0x70
[  219.187239]  [&lt;ffffffff810dc454&gt;] ? enqueue_entity+0x204/0xdf0
[  219.187240]  [&lt;ffffffff816ac048&gt;] __netif_receive_skb+0x18/0x60
[  219.187242]  [&lt;ffffffff816ad1ce&gt;] process_backlog+0x9e/0x140
[  219.187243]  [&lt;ffffffff816ac8ec&gt;] net_rx_action+0x22c/0x370
[  219.187245]  [&lt;ffffffff817cd352&gt;] __do_softirq+0x112/0x2e7
[  219.187247]  [&lt;ffffffff817cc3bc&gt;] do_softirq_own_stack+0x1c/0x30
[  219.187247]  &lt;EOI&gt;
[  219.187248]  [&lt;ffffffff810aa1c8&gt;] do_softirq.part.14+0x38/0x40
[  219.187249]  [&lt;ffffffff810aa24d&gt;] __local_bh_enable_ip+0x7d/0x80
[  219.187254]  [&lt;ffffffffa0408428&gt;] sctp_inq_push+0x68/0x80 [sctp]
[  219.187258]  [&lt;ffffffffa04190f1&gt;] sctp_backlog_rcv+0x151/0x1c0 [sctp]
[  219.187260]  [&lt;ffffffff81692b07&gt;] __release_sock+0x87/0xf0
[  219.187261]  [&lt;ffffffff81692ba0&gt;] release_sock+0x30/0xa0
[  219.187265]  [&lt;ffffffffa040e46d&gt;] sctp_accept+0x17d/0x210 [sctp]
[  219.187266]  [&lt;ffffffff810e7510&gt;] ? prepare_to_wait_event+0xf0/0xf0
[  219.187268]  [&lt;ffffffff8172d52c&gt;] inet_accept+0x3c/0x130
[  219.187269]  [&lt;ffffffff8168d7a3&gt;] SYSC_accept4+0x103/0x210
[  219.187271]  [&lt;ffffffff817ca2ba&gt;] ? _raw_spin_unlock_bh+0x1a/0x20
[  219.187272]  [&lt;ffffffff81692bfc&gt;] ? release_sock+0x8c/0xa0
[  219.187276]  [&lt;ffffffffa0413e22&gt;] ? sctp_inet_listen+0x62/0x1b0 [sctp]
[  219.187277]  [&lt;ffffffff8168f2d0&gt;] SyS_accept+0x10/0x20

Fixes: 860fbbc343bf ("sctp: prepare for socket backlog behavior change")
Cc: Eric Dumazet &lt;eric.dumazet@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: avoid identifying address family many times for a chunk</title>
<updated>2016-07-14T01:10:14+00:00</updated>
<author>
<name>Marcelo Ricardo Leitner</name>
<email>marcelo.leitner@gmail.com</email>
</author>
<published>2016-07-13T18:08:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e7487c86dc5c4a528a7dbd9dc14f453a0de61a84'/>
<id>e7487c86dc5c4a528a7dbd9dc14f453a0de61a84</id>
<content type='text'>
Identifying address family operations during rx path is not something
expensive but it's ugly to the eye to have it done multiple times,
specially when we already validated it during initial rx processing.

This patch takes advantage of the now shared sctp_input_cb and make the
pointer to the operations readily available.

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>
Identifying address family operations during rx path is not something
expensive but it's ugly to the eye to have it done multiple times,
specially when we already validated it during initial rx processing.

This patch takes advantage of the now shared sctp_input_cb and make the
pointer to the operations readily available.

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>
</feed>
