<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/sched, branch v3.18.72</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>net: sched: fix NULL pointer dereference when action calls some targets</title>
<updated>2017-08-30T08:16:54+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2017-08-18T03:01:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=28ae858736a42b37ff4352e3cb46e4a9e9299d2f'/>
<id>28ae858736a42b37ff4352e3cb46e4a9e9299d2f</id>
<content type='text'>
[ Upstream commit 4f8a881acc9d1adaf1e552349a0b1df28933a04c ]

As we know in some target's checkentry it may dereference par.entryinfo
to check entry stuff inside. But when sched action calls xt_check_target,
par.entryinfo is set with NULL. It would cause kernel panic when calling
some targets.

It can be reproduce with:
  # tc qd add dev eth1 ingress handle ffff:
  # tc filter add dev eth1 parent ffff: u32 match u32 0 0 action xt \
    -j ECN --ecn-tcp-remove

It could also crash kernel when using target CLUSTERIP or TPROXY.

By now there's no proper value for par.entryinfo in ipt_init_target,
but it can not be set with NULL. This patch is to void all these
panics by setting it with an ipt_entry obj with all members = 0.

Note that this issue has been there since the very beginning.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&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 4f8a881acc9d1adaf1e552349a0b1df28933a04c ]

As we know in some target's checkentry it may dereference par.entryinfo
to check entry stuff inside. But when sched action calls xt_check_target,
par.entryinfo is set with NULL. It would cause kernel panic when calling
some targets.

It can be reproduce with:
  # tc qd add dev eth1 ingress handle ffff:
  # tc filter add dev eth1 parent ffff: u32 match u32 0 0 action xt \
    -j ECN --ecn-tcp-remove

It could also crash kernel when using target CLUSTERIP or TPROXY.

By now there's no proper value for par.entryinfo in ipt_init_target,
but it can not be set with NULL. This patch is to void all these
panics by setting it with an ipt_entry obj with all members = 0.

Note that this issue has been there since the very beginning.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&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: sched: set xt_tgchk_param par.nft_compat as 0 in ipt_init_target</title>
<updated>2017-08-13T02:24:19+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2017-08-09T10:15:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=74926bfeaf9bab3f6a6bedaef5ff79d32bd38c1a'/>
<id>74926bfeaf9bab3f6a6bedaef5ff79d32bd38c1a</id>
<content type='text'>
[ Upstream commit 96d9703050a0036a3360ec98bb41e107c90664fe ]

Commit 55917a21d0cc ("netfilter: x_tables: add context to know if
extension runs from nft_compat") introduced a member nft_compat to
xt_tgchk_param structure.

But it didn't set it's value for ipt_init_target. With unexpected
value in par.nft_compat, it may return unexpected result in some
target's checkentry.

This patch is to set all it's fields as 0 and only initialize the
non-zero fields in ipt_init_target.

v1-&gt;v2:
  As Wang Cong's suggestion, fix it by setting all it's fields as
  0 and only initializing the non-zero fields.

Fixes: 55917a21d0cc ("netfilter: x_tables: add context to know if extension runs from nft_compat")
Suggested-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 96d9703050a0036a3360ec98bb41e107c90664fe ]

Commit 55917a21d0cc ("netfilter: x_tables: add context to know if
extension runs from nft_compat") introduced a member nft_compat to
xt_tgchk_param structure.

But it didn't set it's value for ipt_init_target. With unexpected
value in par.nft_compat, it may return unexpected result in some
target's checkentry.

This patch is to set all it's fields as 0 and only initialize the
non-zero fields in ipt_init_target.

v1-&gt;v2:
  As Wang Cong's suggestion, fix it by setting all it's fields as
  0 and only initializing the non-zero fields.

Fixes: 55917a21d0cc ("netfilter: x_tables: add context to know if extension runs from nft_compat")
Suggested-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-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>net, sched: fix soft lockup in tc_classify</title>
<updated>2017-08-11T16:30:10+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2016-12-21T17:04:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=83eeedc1595f33d050cbd3d74b7af559f9ee1dd0'/>
<id>83eeedc1595f33d050cbd3d74b7af559f9ee1dd0</id>
<content type='text'>
commit 628185cfddf1dfb701c4efe2cfd72cf5b09f5702 upstream.

Shahar reported a soft lockup in tc_classify(), where we run into an
endless loop when walking the classifier chain due to tp-&gt;next == tp
which is a state we should never run into. The issue only seems to
trigger under load in the tc control path.

What happens is that in tc_ctl_tfilter(), thread A allocates a new
tp, initializes it, sets tp_created to 1, and calls into tp-&gt;ops-&gt;change()
with it. In that classifier callback we had to unlock/lock the rtnl
mutex and returned with -EAGAIN. One reason why we need to drop there
is, for example, that we need to request an action module to be loaded.

This happens via tcf_exts_validate() -&gt; tcf_action_init/_1() meaning
after we loaded and found the requested action, we need to redo the
whole request so we don't race against others. While we had to unlock
rtnl in that time, thread B's request was processed next on that CPU.
Thread B added a new tp instance successfully to the classifier chain.
When thread A returned grabbing the rtnl mutex again, propagating -EAGAIN
and destroying its tp instance which never got linked, we goto replay
and redo A's request.

This time when walking the classifier chain in tc_ctl_tfilter() for
checking for existing tp instances we had a priority match and found
the tp instance that was created and linked by thread B. Now calling
again into tp-&gt;ops-&gt;change() with that tp was successful and returned
without error.

tp_created was never cleared in the second round, thus kernel thinks
that we need to link it into the classifier chain (once again). tp and
*back point to the same object due to the match we had earlier on. Thus
for thread B's already public tp, we reset tp-&gt;next to tp itself and
link it into the chain, which eventually causes the mentioned endless
loop in tc_classify() once a packet hits the data path.

Fix is to clear tp_created at the beginning of each request, also when
we replay it. On the paths that can cause -EAGAIN we already destroy
the original tp instance we had and on replay we really need to start
from scratch. It seems that this issue was first introduced in commit
12186be7d2e1 ("net_cls: fix unconfigured struct tcf_proto keeps chaining
and avoid kernel panic when we use cls_cgroup").

Fixes: 12186be7d2e1 ("net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup")
Reported-by: Shahar Klein &lt;shahark@mellanox.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Tested-by: Shahar Klein &lt;shahark@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Amit Pundir &lt;amit.pundir@linaro.org&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>
commit 628185cfddf1dfb701c4efe2cfd72cf5b09f5702 upstream.

Shahar reported a soft lockup in tc_classify(), where we run into an
endless loop when walking the classifier chain due to tp-&gt;next == tp
which is a state we should never run into. The issue only seems to
trigger under load in the tc control path.

What happens is that in tc_ctl_tfilter(), thread A allocates a new
tp, initializes it, sets tp_created to 1, and calls into tp-&gt;ops-&gt;change()
with it. In that classifier callback we had to unlock/lock the rtnl
mutex and returned with -EAGAIN. One reason why we need to drop there
is, for example, that we need to request an action module to be loaded.

This happens via tcf_exts_validate() -&gt; tcf_action_init/_1() meaning
after we loaded and found the requested action, we need to redo the
whole request so we don't race against others. While we had to unlock
rtnl in that time, thread B's request was processed next on that CPU.
Thread B added a new tp instance successfully to the classifier chain.
When thread A returned grabbing the rtnl mutex again, propagating -EAGAIN
and destroying its tp instance which never got linked, we goto replay
and redo A's request.

This time when walking the classifier chain in tc_ctl_tfilter() for
checking for existing tp instances we had a priority match and found
the tp instance that was created and linked by thread B. Now calling
again into tp-&gt;ops-&gt;change() with that tp was successful and returned
without error.

tp_created was never cleared in the second round, thus kernel thinks
that we need to link it into the classifier chain (once again). tp and
*back point to the same object due to the match we had earlier on. Thus
for thread B's already public tp, we reset tp-&gt;next to tp itself and
link it into the chain, which eventually causes the mentioned endless
loop in tc_classify() once a packet hits the data path.

Fix is to clear tp_created at the beginning of each request, also when
we replay it. On the paths that can cause -EAGAIN we already destroy
the original tp instance we had and on replay we really need to start
from scratch. It seems that this issue was first introduced in commit
12186be7d2e1 ("net_cls: fix unconfigured struct tcf_proto keeps chaining
and avoid kernel panic when we use cls_cgroup").

Fixes: 12186be7d2e1 ("net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup")
Reported-by: Shahar Klein &lt;shahark@mellanox.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Tested-by: Shahar Klein &lt;shahark@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Amit Pundir &lt;amit.pundir@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net sched actions: decrement module reference count after table flush.</title>
<updated>2017-04-22T05:15:02+00:00</updated>
<author>
<name>Roman Mashak</name>
<email>mrv@mojatatu.com</email>
</author>
<published>2017-02-24T16:00:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1280bf203e26550d0a6784ec54f6caf8744caf8f'/>
<id>1280bf203e26550d0a6784ec54f6caf8744caf8f</id>
<content type='text'>
commit edb9d1bff4bbe19b8ae0e71b1f38732591a9eeb2 upstream.

When tc actions are loaded as a module and no actions have been installed,
flushing them would result in actions removed from the memory, but modules
reference count not being decremented, so that the modules would not be
unloaded.

Following is example with GACT action:

% sudo modprobe act_gact
% lsmod
Module                  Size  Used by
act_gact               16384  0
%
% sudo tc actions ls action gact
%
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  1
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  2
% sudo rmmod act_gact
rmmod: ERROR: Module act_gact is in use
....

After the fix:
% lsmod
Module                  Size  Used by
act_gact               16384  0
%
% sudo tc actions add action pass index 1
% sudo tc actions add action pass index 2
% sudo tc actions add action pass index 3
% lsmod
Module                  Size  Used by
act_gact               16384  3
%
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  0
%
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  0
% sudo rmmod act_gact
% lsmod
Module                  Size  Used by
%

Fixes: f97017cdefef ("net-sched: Fix actions flushing")
Signed-off-by: Roman Mashak &lt;mrv@mojatatu.com&gt;
Signed-off-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Cong Wang &lt;xiyou.wangcong@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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit edb9d1bff4bbe19b8ae0e71b1f38732591a9eeb2 upstream.

When tc actions are loaded as a module and no actions have been installed,
flushing them would result in actions removed from the memory, but modules
reference count not being decremented, so that the modules would not be
unloaded.

Following is example with GACT action:

% sudo modprobe act_gact
% lsmod
Module                  Size  Used by
act_gact               16384  0
%
% sudo tc actions ls action gact
%
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  1
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  2
% sudo rmmod act_gact
rmmod: ERROR: Module act_gact is in use
....

After the fix:
% lsmod
Module                  Size  Used by
act_gact               16384  0
%
% sudo tc actions add action pass index 1
% sudo tc actions add action pass index 2
% sudo tc actions add action pass index 3
% lsmod
Module                  Size  Used by
act_gact               16384  3
%
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  0
%
% sudo tc actions flush action gact
% lsmod
Module                  Size  Used by
act_gact               16384  0
% sudo rmmod act_gact
% lsmod
Module                  Size  Used by
%

Fixes: f97017cdefef ("net-sched: Fix actions flushing")
Signed-off-by: Roman Mashak &lt;mrv@mojatatu.com&gt;
Signed-off-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Cong Wang &lt;xiyou.wangcong@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>netem: Segment GSO packets on enqueue</title>
<updated>2016-07-12T12:48:12+00:00</updated>
<author>
<name>Neil Horman</name>
<email>nhorman@tuxdriver.com</email>
</author>
<published>2016-05-02T16:20:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=3f6683aa55a4be9867b4128f396aa955b19db78b'/>
<id>3f6683aa55a4be9867b4128f396aa955b19db78b</id>
<content type='text'>
[ Upstream commit 6071bd1aa13ed9e41824bafad845b7b7f4df5cfd ]

This was recently reported to me, and reproduced on the latest net kernel,
when attempting to run netperf from a host that had a netem qdisc attached
to the egress interface:

[  788.073771] ---------------------[ cut here ]---------------------------
[  788.096716] WARNING: at net/core/dev.c:2253 skb_warn_bad_offload+0xcd/0xda()
[  788.129521] bnx2: caps=(0x00000001801949b3, 0x0000000000000000) len=2962
data_len=0 gso_size=1448 gso_type=1 ip_summed=3
[  788.182150] Modules linked in: sch_netem kvm_amd kvm crc32_pclmul ipmi_ssif
ghash_clmulni_intel sp5100_tco amd64_edac_mod aesni_intel lrw gf128mul
glue_helper ablk_helper edac_mce_amd cryptd pcspkr sg edac_core hpilo ipmi_si
i2c_piix4 k10temp fam15h_power hpwdt ipmi_msghandler shpchp acpi_power_meter
pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c
sd_mod crc_t10dif crct10dif_generic mgag200 syscopyarea sysfillrect sysimgblt
i2c_algo_bit drm_kms_helper ahci ata_generic pata_acpi ttm libahci
crct10dif_pclmul pata_atiixp tg3 libata crct10dif_common drm crc32c_intel ptp
serio_raw bnx2 r8169 hpsa pps_core i2c_core mii dm_mirror dm_region_hash dm_log
dm_mod
[  788.465294] CPU: 16 PID: 0 Comm: swapper/16 Tainted: G        W
------------   3.10.0-327.el7.x86_64 #1
[  788.511521] Hardware name: HP ProLiant DL385p Gen8, BIOS A28 12/17/2012
[  788.542260]  ffff880437c036b8 f7afc56532a53db9 ffff880437c03670
ffffffff816351f1
[  788.576332]  ffff880437c036a8 ffffffff8107b200 ffff880633e74200
ffff880231674000
[  788.611943]  0000000000000001 0000000000000003 0000000000000000
ffff880437c03710
[  788.647241] Call Trace:
[  788.658817]  &lt;IRQ&gt;  [&lt;ffffffff816351f1&gt;] dump_stack+0x19/0x1b
[  788.686193]  [&lt;ffffffff8107b200&gt;] warn_slowpath_common+0x70/0xb0
[  788.713803]  [&lt;ffffffff8107b29c&gt;] warn_slowpath_fmt+0x5c/0x80
[  788.741314]  [&lt;ffffffff812f92f3&gt;] ? ___ratelimit+0x93/0x100
[  788.767018]  [&lt;ffffffff81637f49&gt;] skb_warn_bad_offload+0xcd/0xda
[  788.796117]  [&lt;ffffffff8152950c&gt;] skb_checksum_help+0x17c/0x190
[  788.823392]  [&lt;ffffffffa01463a1&gt;] netem_enqueue+0x741/0x7c0 [sch_netem]
[  788.854487]  [&lt;ffffffff8152cb58&gt;] dev_queue_xmit+0x2a8/0x570
[  788.880870]  [&lt;ffffffff8156ae1d&gt;] ip_finish_output+0x53d/0x7d0
...

The problem occurs because netem is not prepared to handle GSO packets (as it
uses skb_checksum_help in its enqueue path, which cannot manipulate these
frames).

The solution I think is to simply segment the skb in a simmilar fashion to the
way we do in __dev_queue_xmit (via validate_xmit_skb), with some minor changes.
When we decide to corrupt an skb, if the frame is GSO, we segment it, corrupt
the first segment, and enqueue the remaining ones.

tested successfully by myself on the latest net kernel, to which this applies

Signed-off-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
CC: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
CC: "David S. Miller" &lt;davem@davemloft.net&gt;
CC: netem@lists.linux-foundation.org
CC: eric.dumazet@gmail.com
CC: stephen@networkplumber.org
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6071bd1aa13ed9e41824bafad845b7b7f4df5cfd ]

This was recently reported to me, and reproduced on the latest net kernel,
when attempting to run netperf from a host that had a netem qdisc attached
to the egress interface:

[  788.073771] ---------------------[ cut here ]---------------------------
[  788.096716] WARNING: at net/core/dev.c:2253 skb_warn_bad_offload+0xcd/0xda()
[  788.129521] bnx2: caps=(0x00000001801949b3, 0x0000000000000000) len=2962
data_len=0 gso_size=1448 gso_type=1 ip_summed=3
[  788.182150] Modules linked in: sch_netem kvm_amd kvm crc32_pclmul ipmi_ssif
ghash_clmulni_intel sp5100_tco amd64_edac_mod aesni_intel lrw gf128mul
glue_helper ablk_helper edac_mce_amd cryptd pcspkr sg edac_core hpilo ipmi_si
i2c_piix4 k10temp fam15h_power hpwdt ipmi_msghandler shpchp acpi_power_meter
pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c
sd_mod crc_t10dif crct10dif_generic mgag200 syscopyarea sysfillrect sysimgblt
i2c_algo_bit drm_kms_helper ahci ata_generic pata_acpi ttm libahci
crct10dif_pclmul pata_atiixp tg3 libata crct10dif_common drm crc32c_intel ptp
serio_raw bnx2 r8169 hpsa pps_core i2c_core mii dm_mirror dm_region_hash dm_log
dm_mod
[  788.465294] CPU: 16 PID: 0 Comm: swapper/16 Tainted: G        W
------------   3.10.0-327.el7.x86_64 #1
[  788.511521] Hardware name: HP ProLiant DL385p Gen8, BIOS A28 12/17/2012
[  788.542260]  ffff880437c036b8 f7afc56532a53db9 ffff880437c03670
ffffffff816351f1
[  788.576332]  ffff880437c036a8 ffffffff8107b200 ffff880633e74200
ffff880231674000
[  788.611943]  0000000000000001 0000000000000003 0000000000000000
ffff880437c03710
[  788.647241] Call Trace:
[  788.658817]  &lt;IRQ&gt;  [&lt;ffffffff816351f1&gt;] dump_stack+0x19/0x1b
[  788.686193]  [&lt;ffffffff8107b200&gt;] warn_slowpath_common+0x70/0xb0
[  788.713803]  [&lt;ffffffff8107b29c&gt;] warn_slowpath_fmt+0x5c/0x80
[  788.741314]  [&lt;ffffffff812f92f3&gt;] ? ___ratelimit+0x93/0x100
[  788.767018]  [&lt;ffffffff81637f49&gt;] skb_warn_bad_offload+0xcd/0xda
[  788.796117]  [&lt;ffffffff8152950c&gt;] skb_checksum_help+0x17c/0x190
[  788.823392]  [&lt;ffffffffa01463a1&gt;] netem_enqueue+0x741/0x7c0 [sch_netem]
[  788.854487]  [&lt;ffffffff8152cb58&gt;] dev_queue_xmit+0x2a8/0x570
[  788.880870]  [&lt;ffffffff8156ae1d&gt;] ip_finish_output+0x53d/0x7d0
...

The problem occurs because netem is not prepared to handle GSO packets (as it
uses skb_checksum_help in its enqueue path, which cannot manipulate these
frames).

The solution I think is to simply segment the skb in a simmilar fashion to the
way we do in __dev_queue_xmit (via validate_xmit_skb), with some minor changes.
When we decide to corrupt an skb, if the frame is GSO, we segment it, corrupt
the first segment, and enqueue the remaining ones.

tested successfully by myself on the latest net kernel, to which this applies

Signed-off-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
CC: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
CC: "David S. Miller" &lt;davem@davemloft.net&gt;
CC: netem@lists.linux-foundation.org
CC: eric.dumazet@gmail.com
CC: stephen@networkplumber.org
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sch_dsmark: update backlog as well</title>
<updated>2016-07-12T12:48:12+00:00</updated>
<author>
<name>WANG Cong</name>
<email>xiyou.wangcong@gmail.com</email>
</author>
<published>2016-02-25T22:55:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=13baacbfc6feca83054aaff5ecae28a32cb11ea1'/>
<id>13baacbfc6feca83054aaff5ecae28a32cb11ea1</id>
<content type='text'>
[ Upstream commit bdf17661f63a79c3cb4209b970b1cc39e34f7543 ]

Similarly, we need to update backlog too when we update qlen.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bdf17661f63a79c3cb4209b970b1cc39e34f7543 ]

Similarly, we need to update backlog too when we update qlen.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sch_htb: update backlog as well</title>
<updated>2016-07-12T12:48:11+00:00</updated>
<author>
<name>WANG Cong</name>
<email>xiyou.wangcong@gmail.com</email>
</author>
<published>2016-02-25T22:55:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=8e823c17efb21e41af9645ceef7be027895f72fa'/>
<id>8e823c17efb21e41af9645ceef7be027895f72fa</id>
<content type='text'>
[ Upstream commit 431e3a8e36a05a37126f34b41aa3a5a6456af04e ]

We saw qlen!=0 but backlog==0 on our production machine:

qdisc htb 1: dev eth0 root refcnt 2 r2q 10 default 1 direct_packets_stat 0 ver 3.17
 Sent 172680457356 bytes 222469449 pkt (dropped 0, overlimits 123575834 requeues 0)
 backlog 0b 72p requeues 0

The problem is we only count qlen for HTB qdisc but not backlog.
We need to update backlog too when we update qlen, so that we
can at least know the average packet length.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 431e3a8e36a05a37126f34b41aa3a5a6456af04e ]

We saw qlen!=0 but backlog==0 on our production machine:

qdisc htb 1: dev eth0 root refcnt 2 r2q 10 default 1 direct_packets_stat 0 ver 3.17
 Sent 172680457356 bytes 222469449 pkt (dropped 0, overlimits 123575834 requeues 0)
 backlog 0b 72p requeues 0

The problem is we only count qlen for HTB qdisc but not backlog.
We need to update backlog too when we update qlen, so that we
can at least know the average packet length.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net_sched: update hierarchical backlog too</title>
<updated>2016-07-12T12:48:11+00:00</updated>
<author>
<name>WANG Cong</name>
<email>xiyou.wangcong@gmail.com</email>
</author>
<published>2016-02-25T22:55:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=678b209d4d7d02a11726957599d7462d884df4ac'/>
<id>678b209d4d7d02a11726957599d7462d884df4ac</id>
<content type='text'>
[ Upstream commit 2ccccf5fb43ff62b2b96cc58d95fc0b3596516e4 ]

When the bottom qdisc decides to, for example, drop some packet,
it calls qdisc_tree_decrease_qlen() to update the queue length
for all its ancestors, we need to update the backlog too to
keep the stats on root qdisc accurate.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2ccccf5fb43ff62b2b96cc58d95fc0b3596516e4 ]

When the bottom qdisc decides to, for example, drop some packet,
it calls qdisc_tree_decrease_qlen() to update the queue length
for all its ancestors, we need to update the backlog too to
keep the stats on root qdisc accurate.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net_sched: introduce qdisc_replace() helper</title>
<updated>2016-07-12T12:48:10+00:00</updated>
<author>
<name>WANG Cong</name>
<email>xiyou.wangcong@gmail.com</email>
</author>
<published>2016-02-25T22:55:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=cea69b2c4be114ecc6a47e9857673734fbd134cc'/>
<id>cea69b2c4be114ecc6a47e9857673734fbd134cc</id>
<content type='text'>
[ Upstream commit 86a7996cc8a078793670d82ed97d5a99bb4e8496 ]

Remove nearly duplicated code and prepare for the following patch.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 86a7996cc8a078793670d82ed97d5a99bb4e8496 ]

Remove nearly duplicated code and prepare for the following patch.

Cc: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Acked-by: Jamal Hadi Salim &lt;jhs@mojatatu.com&gt;
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: sched: do not requeue a NULL skb</title>
<updated>2016-07-12T12:48:08+00:00</updated>
<author>
<name>Lars Persson</name>
<email>lars.persson@axis.com</email>
</author>
<published>2016-04-12T06:45:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=67bc16d0f4740552793b4915ef67e1b9b11752ee'/>
<id>67bc16d0f4740552793b4915ef67e1b9b11752ee</id>
<content type='text'>
[ Upstream commit 3dcd493fbebfd631913df6e2773cc295d3bf7d22 ]

A failure in validate_xmit_skb_list() triggered an unconditional call
to dev_requeue_skb with skb=NULL. This slowly grows the queue
discipline's qlen count until all traffic through the queue stops.

We take the optimistic approach and continue running the queue after a
failure since it is unknown if later packets also will fail in the
validate path.

Fixes: 55a93b3ea780 ("qdisc: validate skb without holding lock")
Signed-off-by: Lars Persson &lt;larper@axis.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 3dcd493fbebfd631913df6e2773cc295d3bf7d22 ]

A failure in validate_xmit_skb_list() triggered an unconditional call
to dev_requeue_skb with skb=NULL. This slowly grows the queue
discipline's qlen count until all traffic through the queue stops.

We take the optimistic approach and continue running the queue after a
failure since it is unknown if later packets also will fail in the
validate path.

Fixes: 55a93b3ea780 ("qdisc: validate skb without holding lock")
Signed-off-by: Lars Persson &lt;larper@axis.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
