<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/net/core, branch v3.9.6</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>ipv6: do not clear pinet6 field</title>
<updated>2013-05-19T18:38:38+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2013-05-09T10:28:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=285665993541f4f9d8bf80db6d7d27b205aa78b9'/>
<id>285665993541f4f9d8bf80db6d7d27b205aa78b9</id>
<content type='text'>
[ Upstream commit f77d602124d865c38705df7fa25c03de9c284ad2 ]

We have seen multiple NULL dereferences in __inet6_lookup_established()

After analysis, I found that inet6_sk() could be NULL while the
check for sk_family == AF_INET6 was true.

Bug was added in linux-2.6.29 when RCU lookups were introduced in UDP
and TCP stacks.

Once an IPv6 socket, using SLAB_DESTROY_BY_RCU is inserted in a hash
table, we no longer can clear pinet6 field.

This patch extends logic used in commit fcbdf09d9652c891
("net: fix nulls list corruptions in sk_prot_alloc")

TCP/UDP/UDPLite IPv6 protocols provide their own .clear_sk() method
to make sure we do not clear pinet6 field.

At socket clone phase, we do not really care, as cloning the parent (non
NULL) pinet6 is not adding a fatal race.

Signed-off-by: Eric Dumazet &lt;edumazet@google.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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit f77d602124d865c38705df7fa25c03de9c284ad2 ]

We have seen multiple NULL dereferences in __inet6_lookup_established()

After analysis, I found that inet6_sk() could be NULL while the
check for sk_family == AF_INET6 was true.

Bug was added in linux-2.6.29 when RCU lookups were introduced in UDP
and TCP stacks.

Once an IPv6 socket, using SLAB_DESTROY_BY_RCU is inserted in a hash
table, we no longer can clear pinet6 field.

This patch extends logic used in commit fcbdf09d9652c891
("net: fix nulls list corruptions in sk_prot_alloc")

TCP/UDP/UDPLite IPv6 protocols provide their own .clear_sk() method
to make sure we do not clear pinet6 field.

At socket clone phase, we do not really care, as cloning the parent (non
NULL) pinet6 is not adding a fatal race.

Signed-off-by: Eric Dumazet &lt;edumazet@google.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>net: vlan,ethtool: netdev_features_t is more than 32 bit</title>
<updated>2013-05-19T18:38:35+00:00</updated>
<author>
<name>Bjørn Mork</name>
<email>bjorn@mork.no</email>
</author>
<published>2013-05-01T23:06:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=572953b3a5809b0a4129605a5b588946e7e27959'/>
<id>572953b3a5809b0a4129605a5b588946e7e27959</id>
<content type='text'>
[ Upstream commit b29d3145183da4e07d4b570fa8acdd3ac4a5c572 ]

Signed-off-by: Bjørn Mork &lt;bjorn@mork.no&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b29d3145183da4e07d4b570fa8acdd3ac4a5c572 ]

Signed-off-by: Bjørn Mork &lt;bjorn@mork.no&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>net: use netdev_features_t in skb_needs_linearize()</title>
<updated>2013-05-19T18:38:35+00:00</updated>
<author>
<name>Patrick McHardy</name>
<email>kaber@trash.net</email>
</author>
<published>2013-05-01T22:36:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=41d05db1af2c73d17138389271ea149e13b06939'/>
<id>41d05db1af2c73d17138389271ea149e13b06939</id>
<content type='text'>
[ Upstream commit 6708c9e5cc9bfc7c9a00ce9c0fdd0b1d4952b3d1 ]

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6708c9e5cc9bfc7c9a00ce9c0fdd0b1d4952b3d1 ]

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&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>net: rate-limit warn-bad-offload splats.</title>
<updated>2013-04-19T21:57:49+00:00</updated>
<author>
<name>Ben Greear</name>
<email>greearb@candelatech.com</email>
</author>
<published>2013-04-19T10:45:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c846ad9b880ece01bb4d8d07ba917734edf0324f'/>
<id>c846ad9b880ece01bb4d8d07ba917734edf0324f</id>
<content type='text'>
If one does do something unfortunate and allow a
bad offload bug into the kernel, this the
skb_warn_bad_offload can effectively live-lock the
system, filling the logs with the same error over
and over.

Add rate limitation to this so that box remains otherwise
functional in this case.

Signed-off-by: Ben Greear &lt;greearb@candelatech.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>
If one does do something unfortunate and allow a
bad offload bug into the kernel, this the
skb_warn_bad_offload can effectively live-lock the
system, filling the logs with the same error over
and over.

Add rate limitation to this so that box remains otherwise
functional in this case.

Signed-off-by: Ben Greear &lt;greearb@candelatech.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rtnetlink: Call nlmsg_parse() with correct header length</title>
<updated>2013-04-08T21:12:26+00:00</updated>
<author>
<name>Michael Riesch</name>
<email>michael.riesch@omicron.at</email>
</author>
<published>2013-04-08T05:45:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=88c5b5ce5cb57af6ca2a7cf4d5715fa320448ff9'/>
<id>88c5b5ce5cb57af6ca2a7cf4d5715fa320448ff9</id>
<content type='text'>
Signed-off-by: Michael Riesch &lt;michael.riesch@omicron.at&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Jiri Benc &lt;jbenc@redhat.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: linux-kernel@vger.kernel.org
Acked-by: Mark Rustad &lt;mark.d.rustad@intel.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>
Signed-off-by: Michael Riesch &lt;michael.riesch@omicron.at&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Jiri Benc &lt;jbenc@redhat.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: linux-kernel@vger.kernel.org
Acked-by: Mark Rustad &lt;mark.d.rustad@intel.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: don't reset nf_trace in nf_reset()</title>
<updated>2013-04-05T19:38:10+00:00</updated>
<author>
<name>Patrick McHardy</name>
<email>kaber@trash.net</email>
</author>
<published>2013-04-05T18:42:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=124dff01afbdbff251f0385beca84ba1b9adda68'/>
<id>124dff01afbdbff251f0385beca84ba1b9adda68</id>
<content type='text'>
Commit 130549fe ("netfilter: reset nf_trace in nf_reset") added code
to reset nf_trace in nf_reset(). This is wrong and unnecessary.

nf_reset() is used in the following cases:

- when passing packets up the the socket layer, at which point we want to
  release all netfilter references that might keep modules pinned while
  the packet is queued. nf_trace doesn't matter anymore at this point.

- when encapsulating or decapsulating IPsec packets. We want to continue
  tracing these packets after IPsec processing.

- when passing packets through virtual network devices. Only devices on
  that encapsulate in IPv4/v6 matter since otherwise nf_trace is not
  used anymore. Its not entirely clear whether those packets should
  be traced after that, however we've always done that.

- when passing packets through virtual network devices that make the
  packet cross network namespace boundaries. This is the only cases
  where we clearly want to reset nf_trace and is also what the
  original patch intended to fix.

Add a new function nf_reset_trace() and use it in dev_forward_skb() to
fix this properly.

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&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>
Commit 130549fe ("netfilter: reset nf_trace in nf_reset") added code
to reset nf_trace in nf_reset(). This is wrong and unnecessary.

nf_reset() is used in the following cases:

- when passing packets up the the socket layer, at which point we want to
  release all netfilter references that might keep modules pinned while
  the packet is queued. nf_trace doesn't matter anymore at this point.

- when encapsulating or decapsulating IPsec packets. We want to continue
  tracing these packets after IPsec processing.

- when passing packets through virtual network devices. Only devices on
  that encapsulate in IPv4/v6 matter since otherwise nf_trace is not
  used anymore. Its not entirely clear whether those packets should
  be traced after that, however we've always done that.

- when passing packets through virtual network devices that make the
  packet cross network namespace boundaries. This is the only cases
  where we clearly want to reset nf_trace and is also what the
  original patch intended to fix.

Add a new function nf_reset_trace() and use it in dev_forward_skb() to
fix this properly.

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: count hw_addr syncs so that unsync works properly.</title>
<updated>2013-04-05T04:18:46+00:00</updated>
<author>
<name>Vlad Yasevich</name>
<email>vyasevic@redhat.com</email>
</author>
<published>2013-04-02T21:10:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4543fbefe6e06a9e40d9f2b28d688393a299f079'/>
<id>4543fbefe6e06a9e40d9f2b28d688393a299f079</id>
<content type='text'>
A few drivers use dev_uc_sync/unsync to synchronize the
address lists from master down to slave/lower devices.  In
some cases (bond/team) a single address list is synched down
to multiple devices.  At the time of unsync, we have a leak
in these lower devices, because "synced" is treated as a
boolean and the address will not be unsynced for anything after
the first device/call.

Treat "synced" as a count (same as refcount) and allow all
unsync calls to work.

Signed-off-by: Vlad Yasevich &lt;vyasevic@redhat.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>
A few drivers use dev_uc_sync/unsync to synchronize the
address lists from master down to slave/lower devices.  In
some cases (bond/team) a single address list is synched down
to multiple devices.  At the time of unsync, we have a leak
in these lower devices, because "synced" is treated as a
boolean and the address will not be unsynced for anything after
the first device/call.

Treat "synced" as a count (same as refcount) and allow all
unsync calls to work.

Signed-off-by: Vlad Yasevich &lt;vyasevic@redhat.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>2013-04-01T15:06:30+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2013-04-01T15:06:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ff3421dee60928de95b68a13a1b64125b62b10a4'/>
<id>ff3421dee60928de95b68a13a1b64125b62b10a4</id>
<content type='text'>
Pull networking fixes from David Miller:

 1) sadb_msg prepared for IPSEC userspace forgets to initialize the
    satype field, fix from Nicolas Dichtel.

 2) Fix mac80211 synchronization during station removal, from Johannes
    Berg.

 3) Fix IPSEC sequence number notifications when they wrap, from Steffen
    Klassert.

 4) Fix cfg80211 wdev tracing crashes when add_virtual_intf() returns an
    error pointer, from Johannes Berg.

 5) In mac80211, don't call into the channel context code with the
    interface list mutex held.  From Johannes Berg.

 6) In mac80211, if we don't actually associate, do not restart the STA
    timer, otherwise we can crash.  From Ben Greear.

 7) Missing dma_mapping_error() check in e1000, ixgb, and e1000e.  From
    Christoph Paasch.

 8) Fix sja1000 driver defines to not conflict with SH port, from Marc
    Kleine-Budde.

 9) Don't call il4965_rs_use_green with a NULL station, from Colin Ian
    King.

10) Suspend/Resume in the FEC driver fail because the buffer descriptors
    are not initialized at all the moments in which they should.  Fix
    from Frank Li.

11) cpsw and davinci_emac drivers both use the wrong interface to
    restart a stopped TX queue.  Use netif_wake_queue not
    netif_start_queue, the latter is for initialization/bringup not
    active management of the queue.  From Mugunthan V N.

12) Fix regression in rate calculations done by
    psched_ratecfg_precompute(), missing u64 type promotion.  From
    Sergey Popovich.

13) Fix length overflow in tg3 VPD parsing, from Kees Cook.

14) AOE driver fails to allocate enough headroom, resulting in crashes.
    Fix from Eric Dumazet.

15) RX overflow happens too quickly in sky2 driver because pause packet
    thresholds are not programmed correctly.  From Mirko Lindner.

16) Bonding driver manages arp_interval and miimon settings incorrectly,
    disabling one unintentionally disables both.  Fix from Nikolay
    Aleksandrov.

17) smsc75xx drivers don't program the RX mac properly for jumbo frames.
    Fix from Steve Glendinning.

18) Fix off-by-one in Codel packet scheduler.  From Vijay Subramanian.

19) Fix packet corruption in atl1c by disabling MSI support, from Hannes
    Frederic Sowa.

20) netdev_rx_handler_unregister() needs a synchronize_net() to fix
    crashes in bonding driver unload stress tests.  From Eric Dumazet.

21) rxlen field of ks8851 RX packet descriptors not interpreted
    correctly (it is 12 bits not 16 bits, so needs to be masked after
    shifting the 32-bit value down 16 bits).  Fix from Max Nekludov.

22) Fix missed RX/TX enable in sh_eth driver due to mishandling of link
    change indications.  From Sergei Shtylyov.

23) Fix crashes during spurious ECI interrupts in sh_eth driver, also
    from Sergei Shtylyov.

24) dm9000 driver initialization is done wrong for revision B devices
    with DSP PHY, from Joseph CHANG.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (53 commits)
  DM9000B: driver initialization upgrade
  sh_eth: make 'link' field of 'struct sh_eth_private' *int*
  sh_eth: workaround for spurious ECI interrupt
  sh_eth: fix handling of no LINK signal
  ks8851: Fix interpretation of rxlen field.
  net: add a synchronize_net() in netdev_rx_handler_unregister()
  MAINTAINERS: Update netxen_nic maintainers list
  atl1e: drop pci-msi support because of packet corruption
  net: fq_codel: Fix off-by-one error
  net: calxedaxgmac: Wake-on-LAN fixes
  net: calxedaxgmac: fix rx ring handling when OOM
  net: core: Remove redundant call to 'nf_reset' in 'dev_forward_skb'
  smsc75xx: fix jumbo frame support
  net: fix the use of this_cpu_ptr
  bonding: fix disabling of arp_interval and miimon
  ipv6: don't accept node local multicast traffic from the wire
  sky2: Threshold for Pause Packet is set wrong
  sky2: Receive Overflows not counted
  aoe: reserve enough headroom on skbs
  line up comment for ndo_bridge_getlink
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:

 1) sadb_msg prepared for IPSEC userspace forgets to initialize the
    satype field, fix from Nicolas Dichtel.

 2) Fix mac80211 synchronization during station removal, from Johannes
    Berg.

 3) Fix IPSEC sequence number notifications when they wrap, from Steffen
    Klassert.

 4) Fix cfg80211 wdev tracing crashes when add_virtual_intf() returns an
    error pointer, from Johannes Berg.

 5) In mac80211, don't call into the channel context code with the
    interface list mutex held.  From Johannes Berg.

 6) In mac80211, if we don't actually associate, do not restart the STA
    timer, otherwise we can crash.  From Ben Greear.

 7) Missing dma_mapping_error() check in e1000, ixgb, and e1000e.  From
    Christoph Paasch.

 8) Fix sja1000 driver defines to not conflict with SH port, from Marc
    Kleine-Budde.

 9) Don't call il4965_rs_use_green with a NULL station, from Colin Ian
    King.

10) Suspend/Resume in the FEC driver fail because the buffer descriptors
    are not initialized at all the moments in which they should.  Fix
    from Frank Li.

11) cpsw and davinci_emac drivers both use the wrong interface to
    restart a stopped TX queue.  Use netif_wake_queue not
    netif_start_queue, the latter is for initialization/bringup not
    active management of the queue.  From Mugunthan V N.

12) Fix regression in rate calculations done by
    psched_ratecfg_precompute(), missing u64 type promotion.  From
    Sergey Popovich.

13) Fix length overflow in tg3 VPD parsing, from Kees Cook.

14) AOE driver fails to allocate enough headroom, resulting in crashes.
    Fix from Eric Dumazet.

15) RX overflow happens too quickly in sky2 driver because pause packet
    thresholds are not programmed correctly.  From Mirko Lindner.

16) Bonding driver manages arp_interval and miimon settings incorrectly,
    disabling one unintentionally disables both.  Fix from Nikolay
    Aleksandrov.

17) smsc75xx drivers don't program the RX mac properly for jumbo frames.
    Fix from Steve Glendinning.

18) Fix off-by-one in Codel packet scheduler.  From Vijay Subramanian.

19) Fix packet corruption in atl1c by disabling MSI support, from Hannes
    Frederic Sowa.

20) netdev_rx_handler_unregister() needs a synchronize_net() to fix
    crashes in bonding driver unload stress tests.  From Eric Dumazet.

21) rxlen field of ks8851 RX packet descriptors not interpreted
    correctly (it is 12 bits not 16 bits, so needs to be masked after
    shifting the 32-bit value down 16 bits).  Fix from Max Nekludov.

22) Fix missed RX/TX enable in sh_eth driver due to mishandling of link
    change indications.  From Sergei Shtylyov.

23) Fix crashes during spurious ECI interrupts in sh_eth driver, also
    from Sergei Shtylyov.

24) dm9000 driver initialization is done wrong for revision B devices
    with DSP PHY, from Joseph CHANG.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (53 commits)
  DM9000B: driver initialization upgrade
  sh_eth: make 'link' field of 'struct sh_eth_private' *int*
  sh_eth: workaround for spurious ECI interrupt
  sh_eth: fix handling of no LINK signal
  ks8851: Fix interpretation of rxlen field.
  net: add a synchronize_net() in netdev_rx_handler_unregister()
  MAINTAINERS: Update netxen_nic maintainers list
  atl1e: drop pci-msi support because of packet corruption
  net: fq_codel: Fix off-by-one error
  net: calxedaxgmac: Wake-on-LAN fixes
  net: calxedaxgmac: fix rx ring handling when OOM
  net: core: Remove redundant call to 'nf_reset' in 'dev_forward_skb'
  smsc75xx: fix jumbo frame support
  net: fix the use of this_cpu_ptr
  bonding: fix disabling of arp_interval and miimon
  ipv6: don't accept node local multicast traffic from the wire
  sky2: Threshold for Pause Packet is set wrong
  sky2: Receive Overflows not counted
  aoe: reserve enough headroom on skbs
  line up comment for ndo_bridge_getlink
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>net: add a synchronize_net() in netdev_rx_handler_unregister()</title>
<updated>2013-03-29T19:38:15+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2013-03-29T03:01:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=00cfec37484761a44a3b6f4675a54caa618210ae'/>
<id>00cfec37484761a44a3b6f4675a54caa618210ae</id>
<content type='text'>
commit 35d48903e97819 (bonding: fix rx_handler locking) added a race
in bonding driver, reported by Steven Rostedt who did a very good
diagnosis :

&lt;quoting Steven&gt;

I'm currently debugging a crash in an old 3.0-rt kernel that one of our
customers is seeing. The bug happens with a stress test that loads and
unloads the bonding module in a loop (I don't know all the details as
I'm not the one that is directly interacting with the customer). But the
bug looks to be something that may still be present and possibly present
in mainline too. It will just be much harder to trigger it in mainline.

In -rt, interrupts are threads, and can schedule in and out just like
any other thread. Note, mainline now supports interrupt threads so this
may be easily reproducible in mainline as well. I don't have the ability
to tell the customer to try mainline or other kernels, so my hands are
somewhat tied to what I can do.

But according to a core dump, I tracked down that the eth irq thread
crashed in bond_handle_frame() here:

        slave = bond_slave_get_rcu(skb-&gt;dev);
        bond = slave-&gt;bond; &lt;--- BUG

the slave returned was NULL and accessing slave-&gt;bond caused a NULL
pointer dereference.

Looking at the code that unregisters the handler:

void netdev_rx_handler_unregister(struct net_device *dev)
{

        ASSERT_RTNL();
        RCU_INIT_POINTER(dev-&gt;rx_handler, NULL);
        RCU_INIT_POINTER(dev-&gt;rx_handler_data, NULL);
}

Which is basically:
        dev-&gt;rx_handler = NULL;
        dev-&gt;rx_handler_data = NULL;

And looking at __netif_receive_skb() we have:

        rx_handler = rcu_dereference(skb-&gt;dev-&gt;rx_handler);
        if (rx_handler) {
                if (pt_prev) {
                        ret = deliver_skb(skb, pt_prev, orig_dev);
                        pt_prev = NULL;
                }
                switch (rx_handler(&amp;skb)) {

My question to all of you is, what stops this interrupt from happening
while the bonding module is unloading?  What happens if the interrupt
triggers and we have this:

        CPU0                    CPU1
        ----                    ----
  rx_handler = skb-&gt;dev-&gt;rx_handler

                        netdev_rx_handler_unregister() {
                           dev-&gt;rx_handler = NULL;
                           dev-&gt;rx_handler_data = NULL;

  rx_handler()
   bond_handle_frame() {
    slave = skb-&gt;dev-&gt;rx_handler;
    bond = slave-&gt;bond; &lt;-- NULL pointer dereference!!!

What protection am I missing in the bond release handler that would
prevent the above from happening?

&lt;/quoting Steven&gt;

We can fix bug this in two ways. First is adding a test in
bond_handle_frame() and others to check if rx_handler_data is NULL.

A second way is adding a synchronize_net() in
netdev_rx_handler_unregister() to make sure that a rcu protected reader
has the guarantee to see a non NULL rx_handler_data.

The second way is better as it avoids an extra test in fast path.

Reported-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Jiri Pirko &lt;jpirko@redhat.com&gt;
Cc: Paul E. McKenney &lt;paulmck@us.ibm.com&gt;
Acked-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Reviewed-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.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>
commit 35d48903e97819 (bonding: fix rx_handler locking) added a race
in bonding driver, reported by Steven Rostedt who did a very good
diagnosis :

&lt;quoting Steven&gt;

I'm currently debugging a crash in an old 3.0-rt kernel that one of our
customers is seeing. The bug happens with a stress test that loads and
unloads the bonding module in a loop (I don't know all the details as
I'm not the one that is directly interacting with the customer). But the
bug looks to be something that may still be present and possibly present
in mainline too. It will just be much harder to trigger it in mainline.

In -rt, interrupts are threads, and can schedule in and out just like
any other thread. Note, mainline now supports interrupt threads so this
may be easily reproducible in mainline as well. I don't have the ability
to tell the customer to try mainline or other kernels, so my hands are
somewhat tied to what I can do.

But according to a core dump, I tracked down that the eth irq thread
crashed in bond_handle_frame() here:

        slave = bond_slave_get_rcu(skb-&gt;dev);
        bond = slave-&gt;bond; &lt;--- BUG

the slave returned was NULL and accessing slave-&gt;bond caused a NULL
pointer dereference.

Looking at the code that unregisters the handler:

void netdev_rx_handler_unregister(struct net_device *dev)
{

        ASSERT_RTNL();
        RCU_INIT_POINTER(dev-&gt;rx_handler, NULL);
        RCU_INIT_POINTER(dev-&gt;rx_handler_data, NULL);
}

Which is basically:
        dev-&gt;rx_handler = NULL;
        dev-&gt;rx_handler_data = NULL;

And looking at __netif_receive_skb() we have:

        rx_handler = rcu_dereference(skb-&gt;dev-&gt;rx_handler);
        if (rx_handler) {
                if (pt_prev) {
                        ret = deliver_skb(skb, pt_prev, orig_dev);
                        pt_prev = NULL;
                }
                switch (rx_handler(&amp;skb)) {

My question to all of you is, what stops this interrupt from happening
while the bonding module is unloading?  What happens if the interrupt
triggers and we have this:

        CPU0                    CPU1
        ----                    ----
  rx_handler = skb-&gt;dev-&gt;rx_handler

                        netdev_rx_handler_unregister() {
                           dev-&gt;rx_handler = NULL;
                           dev-&gt;rx_handler_data = NULL;

  rx_handler()
   bond_handle_frame() {
    slave = skb-&gt;dev-&gt;rx_handler;
    bond = slave-&gt;bond; &lt;-- NULL pointer dereference!!!

What protection am I missing in the bond release handler that would
prevent the above from happening?

&lt;/quoting Steven&gt;

We can fix bug this in two ways. First is adding a test in
bond_handle_frame() and others to check if rx_handler_data is NULL.

A second way is adding a synchronize_net() in
netdev_rx_handler_unregister() to make sure that a rcu protected reader
has the guarantee to see a non NULL rx_handler_data.

The second way is better as it avoids an extra test in fast path.

Reported-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Jiri Pirko &lt;jpirko@redhat.com&gt;
Cc: Paul E. McKenney &lt;paulmck@us.ibm.com&gt;
Acked-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Reviewed-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: core: Remove redundant call to 'nf_reset' in 'dev_forward_skb'</title>
<updated>2013-03-29T19:25:28+00:00</updated>
<author>
<name>Shmulik Ladkani</name>
<email>shmulik.ladkani@gmail.com</email>
</author>
<published>2013-03-27T23:13:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a561cf7edf9863198bfccecfc5cfe26d951ebd20'/>
<id>a561cf7edf9863198bfccecfc5cfe26d951ebd20</id>
<content type='text'>
'nf_reset' is called just prior calling 'netif_rx'.
No need to call it twice.

Reported-by: Igor Michailov &lt;rgohita@gmail.com&gt;
Signed-off-by: Shmulik Ladkani &lt;shmulik.ladkani@gmail.com&gt;
Acked-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>
'nf_reset' is called just prior calling 'netif_rx'.
No need to call it twice.

Reported-by: Igor Michailov &lt;rgohita@gmail.com&gt;
Signed-off-by: Shmulik Ladkani &lt;shmulik.ladkani@gmail.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
