<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include, branch v3.10.45</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ALSA: control: Protect user controls against concurrent access</title>
<updated>2014-06-26T19:12:43+00:00</updated>
<author>
<name>Lars-Peter Clausen</name>
<email>lars@metafoo.de</email>
</author>
<published>2014-06-18T11:32:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=be3bae536eaf0a98926006a8ec00417a48b6a587'/>
<id>be3bae536eaf0a98926006a8ec00417a48b6a587</id>
<content type='text'>
commit 07f4d9d74a04aa7c72c5dae0ef97565f28f17b92 upstream.

The user-control put and get handlers as well as the tlv do not protect against
concurrent access from multiple threads. Since the state of the control is not
updated atomically it is possible that either two write operations or a write
and a read operation race against each other. Both can lead to arbitrary memory
disclosure. This patch introduces a new lock that protects user-controls from
concurrent access. Since applications typically access controls sequentially
than in parallel a single lock per card should be fine.

Signed-off-by: Lars-Peter Clausen &lt;lars@metafoo.de&gt;
Acked-by: Jaroslav Kysela &lt;perex@perex.cz&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&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 07f4d9d74a04aa7c72c5dae0ef97565f28f17b92 upstream.

The user-control put and get handlers as well as the tlv do not protect against
concurrent access from multiple threads. Since the state of the control is not
updated atomically it is possible that either two write operations or a write
and a read operation race against each other. Both can lead to arbitrary memory
disclosure. This patch introduces a new lock that protects user-controls from
concurrent access. Since applications typically access controls sequentially
than in parallel a single lock per card should be fine.

Signed-off-by: Lars-Peter Clausen &lt;lars@metafoo.de&gt;
Acked-by: Jaroslav Kysela &lt;perex@perex.cz&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: compress: Cancel the optimization of compiler and fix the size of struct for all platform.</title>
<updated>2014-06-26T19:12:41+00:00</updated>
<author>
<name>Wang, Xiaoming</name>
<email>xiaoming.wang@intel.com</email>
</author>
<published>2014-06-12T22:47:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d2c44167ecbabae2c55f4777f351203282cb8ab2'/>
<id>d2c44167ecbabae2c55f4777f351203282cb8ab2</id>
<content type='text'>
commit 2bd0ae464a6cf7363bbf72c8545e0aa43caa57f0 upstream.

Cancel the optimization of compiler for struct snd_compr_avail
which size will be 0x1c in 32bit kernel while 0x20 in 64bit
kernel under the optimizer. That will make compaction between
32bit and 64bit. So add packed to fix the size of struct
snd_compr_avail to 0x1c for all platform.

Signed-off-by: Zhang Dongxing &lt;dongxing.zhang@intel.com&gt;
Signed-off-by: xiaoming wang &lt;xiaoming.wang@intel.com&gt;
Acked-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&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 2bd0ae464a6cf7363bbf72c8545e0aa43caa57f0 upstream.

Cancel the optimization of compiler for struct snd_compr_avail
which size will be 0x1c in 32bit kernel while 0x20 in 64bit
kernel under the optimizer. That will make compaction between
32bit and 64bit. So add packed to fix the size of struct
snd_compr_avail to 0x1c for all platform.

Signed-off-by: Zhang Dongxing &lt;dongxing.zhang@intel.com&gt;
Signed-off-by: xiaoming wang &lt;xiaoming.wang@intel.com&gt;
Acked-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>team: fix mtu setting</title>
<updated>2014-06-26T19:12:38+00:00</updated>
<author>
<name>Jiri Pirko</name>
<email>jiri@resnulli.us</email>
</author>
<published>2014-05-29T18:46:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=35f8524540ad82b1af784ebd7002753ffb8e953c'/>
<id>35f8524540ad82b1af784ebd7002753ffb8e953c</id>
<content type='text'>
[ Upstream commit 9d0d68faea6962d62dd501cd6e71ce5cc8ed262b ]

Now it is not possible to set mtu to team device which has a port
enslaved to it. The reason is that when team_change_mtu() calls
dev_set_mtu() for port device, notificator for NETDEV_PRECHANGEMTU
event is called and team_device_event() returns NOTIFY_BAD forbidding
the change. So fix this by returning NOTIFY_DONE here in case team is
changing mtu in team_change_mtu().

Introduced-by: 3d249d4c "net: introduce ethernet teaming device"
Signed-off-by: Jiri Pirko &lt;jiri@resnulli.us&gt;
Acked-by: Flavio Leitner &lt;fbl@redhat.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 9d0d68faea6962d62dd501cd6e71ce5cc8ed262b ]

Now it is not possible to set mtu to team device which has a port
enslaved to it. The reason is that when team_change_mtu() calls
dev_set_mtu() for port device, notificator for NETDEV_PRECHANGEMTU
event is called and team_device_event() returns NOTIFY_BAD forbidding
the change. So fix this by returning NOTIFY_DONE here in case team is
changing mtu in team_change_mtu().

Introduced-by: 3d249d4c "net: introduce ethernet teaming device"
Signed-off-by: Jiri Pirko &lt;jiri@resnulli.us&gt;
Acked-by: Flavio Leitner &lt;fbl@redhat.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: fix inet_getid() and ipv6_select_ident() bugs</title>
<updated>2014-06-26T19:12:38+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2014-05-29T15:45:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=25bc3126ccbe553b5cc293ca9c77d44bb40ff62d'/>
<id>25bc3126ccbe553b5cc293ca9c77d44bb40ff62d</id>
<content type='text'>
[ Upstream commit 39c36094d78c39e038c1e499b2364e13bce36f54 ]

I noticed we were sending wrong IPv4 ID in TCP flows when MTU discovery
is disabled.
Note how GSO/TSO packets do not have monotonically incrementing ID.

06:37:41.575531 IP (id 14227, proto: TCP (6), length: 4396)
06:37:41.575534 IP (id 14272, proto: TCP (6), length: 65212)
06:37:41.575544 IP (id 14312, proto: TCP (6), length: 57972)
06:37:41.575678 IP (id 14317, proto: TCP (6), length: 7292)
06:37:41.575683 IP (id 14361, proto: TCP (6), length: 63764)

It appears I introduced this bug in linux-3.1.

inet_getid() must return the old value of peer-&gt;ip_id_count,
not the new one.

Lets revert this part, and remove the prevention of
a null identification field in IPv6 Fragment Extension Header,
which is dubious and not even done properly.

Fixes: 87c48fa3b463 ("ipv6: make fragment identifications less predictable")
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 39c36094d78c39e038c1e499b2364e13bce36f54 ]

I noticed we were sending wrong IPv4 ID in TCP flows when MTU discovery
is disabled.
Note how GSO/TSO packets do not have monotonically incrementing ID.

06:37:41.575531 IP (id 14227, proto: TCP (6), length: 4396)
06:37:41.575534 IP (id 14272, proto: TCP (6), length: 65212)
06:37:41.575544 IP (id 14312, proto: TCP (6), length: 57972)
06:37:41.575678 IP (id 14317, proto: TCP (6), length: 7292)
06:37:41.575683 IP (id 14361, proto: TCP (6), length: 63764)

It appears I introduced this bug in linux-3.1.

inet_getid() must return the old value of peer-&gt;ip_id_count,
not the new one.

Lets revert this part, and remove the prevention of
a null identification field in IPv6 Fragment Extension Header,
which is dubious and not even done properly.

Fixes: 87c48fa3b463 ("ipv6: make fragment identifications less predictable")
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>netlink: Only check file credentials for implicit destinations</title>
<updated>2014-06-26T19:12:37+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2014-05-30T18:04:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8ab02acdf274cbd6b10f7dd990f42c9b40469141'/>
<id>8ab02acdf274cbd6b10f7dd990f42c9b40469141</id>
<content type='text'>
[ Upstream commit 2d7a85f4b06e9c27ff629f07a524c48074f07f81 ]

It was possible to get a setuid root or setcap executable to write to
it's stdout or stderr (which has been set made a netlink socket) and
inadvertently reconfigure the networking stack.

To prevent this we check that both the creator of the socket and
the currentl applications has permission to reconfigure the network
stack.

Unfortunately this breaks Zebra which always uses sendto/sendmsg
and creates it's socket without any privileges.

To keep Zebra working don't bother checking if the creator of the
socket has privilege when a destination address is specified.  Instead
rely exclusively on the privileges of the sender of the socket.

Note from Andy: This is exactly Eric's code except for some comment
clarifications and formatting fixes.  Neither I nor, I think, anyone
else is thrilled with this approach, but I'm hesitant to wait on a
better fix since 3.15 is almost here.

Note to stable maintainers: This is a mess.  An earlier series of
patches in 3.15 fix a rather serious security issue (CVE-2014-0181),
but they did so in a way that breaks Zebra.  The offending series
includes:

    commit aa4cf9452f469f16cea8c96283b641b4576d4a7b
    Author: Eric W. Biederman &lt;ebiederm@xmission.com&gt;
    Date:   Wed Apr 23 14:28:03 2014 -0700

        net: Add variants of capable for use on netlink messages

If a given kernel version is missing that series of fixes, it's
probably worth backporting it and this patch.  if that series is
present, then this fix is critical if you care about Zebra.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.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 2d7a85f4b06e9c27ff629f07a524c48074f07f81 ]

It was possible to get a setuid root or setcap executable to write to
it's stdout or stderr (which has been set made a netlink socket) and
inadvertently reconfigure the networking stack.

To prevent this we check that both the creator of the socket and
the currentl applications has permission to reconfigure the network
stack.

Unfortunately this breaks Zebra which always uses sendto/sendmsg
and creates it's socket without any privileges.

To keep Zebra working don't bother checking if the creator of the
socket has privilege when a destination address is specified.  Instead
rely exclusively on the privileges of the sender of the socket.

Note from Andy: This is exactly Eric's code except for some comment
clarifications and formatting fixes.  Neither I nor, I think, anyone
else is thrilled with this approach, but I'm hesitant to wait on a
better fix since 3.15 is almost here.

Note to stable maintainers: This is a mess.  An earlier series of
patches in 3.15 fix a rather serious security issue (CVE-2014-0181),
but they did so in a way that breaks Zebra.  The offending series
includes:

    commit aa4cf9452f469f16cea8c96283b641b4576d4a7b
    Author: Eric W. Biederman &lt;ebiederm@xmission.com&gt;
    Date:   Wed Apr 23 14:28:03 2014 -0700

        net: Add variants of capable for use on netlink messages

If a given kernel version is missing that series of fixes, it's
probably worth backporting it and this patch.  if that series is
present, then this fix is critical if you care about Zebra.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.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: Add variants of capable for use on netlink messages</title>
<updated>2014-06-26T19:12:37+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2014-04-23T21:28:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=738f378d77b04f685f2cd01aa4240d1bce5c9668'/>
<id>738f378d77b04f685f2cd01aa4240d1bce5c9668</id>
<content type='text'>
[ Upstream commit aa4cf9452f469f16cea8c96283b641b4576d4a7b ]

netlink_net_capable - The common case use, for operations that are safe on a network namespace
netlink_capable - For operations that are only known to be safe for the global root
netlink_ns_capable - The general case of capable used to handle special cases

__netlink_ns_capable - Same as netlink_ns_capable except taking a netlink_skb_parms instead of
		       the skbuff of a netlink message.

Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.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 aa4cf9452f469f16cea8c96283b641b4576d4a7b ]

netlink_net_capable - The common case use, for operations that are safe on a network namespace
netlink_capable - For operations that are only known to be safe for the global root
netlink_ns_capable - The general case of capable used to handle special cases

__netlink_ns_capable - Same as netlink_ns_capable except taking a netlink_skb_parms instead of
		       the skbuff of a netlink message.

Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.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: Add variants of capable for use on on sockets</title>
<updated>2014-06-26T19:12:37+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2014-04-23T21:26:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c35b4e287f5ede32bae6db1aef1ae3e9174bb2ff'/>
<id>c35b4e287f5ede32bae6db1aef1ae3e9174bb2ff</id>
<content type='text'>
[ Upstream commit a3b299da869d6e78cf42ae0b1b41797bcb8c5e4b ]

sk_net_capable - The common case, operations that are safe in a network namespace.
sk_capable - Operations that are not known to be safe in a network namespace
sk_ns_capable - The general case for special cases.

Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.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 a3b299da869d6e78cf42ae0b1b41797bcb8c5e4b ]

sk_net_capable - The common case, operations that are safe in a network namespace.
sk_capable - Operations that are not known to be safe in a network namespace
sk_ns_capable - The general case for special cases.

Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.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: Move the permission check in sock_diag_put_filterinfo to packet_diag_dump</title>
<updated>2014-06-26T19:12:37+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2014-04-23T21:26:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f0efa2954c20ab833bf99acba0a0817f1deee9e0'/>
<id>f0efa2954c20ab833bf99acba0a0817f1deee9e0</id>
<content type='text'>
[ Upstream commit a53b72c83a4216f2eb883ed45a0cbce014b8e62d ]

The permission check in sock_diag_put_filterinfo is wrong, and it is so removed
from it's sources it is not clear why it is wrong.  Move the computation
into packet_diag_dump and pass a bool of the result into sock_diag_filterinfo.

This does not yet correct the capability check but instead simply moves it to make
it clear what is going on.

Reported-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.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 a53b72c83a4216f2eb883ed45a0cbce014b8e62d ]

The permission check in sock_diag_put_filterinfo is wrong, and it is so removed
from it's sources it is not clear why it is wrong.  Move the computation
into packet_diag_dump and pass a bool of the result into sock_diag_filterinfo.

This does not yet correct the capability check but instead simply moves it to make
it clear what is going on.

Reported-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.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>fs,userns: Change inode_capable to capable_wrt_inode_uidgid</title>
<updated>2014-06-16T20:42:52+00:00</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@amacapital.net</email>
</author>
<published>2014-06-10T19:45:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4f80c6c1825a91cecf3b3bd19c824e768d98fe48'/>
<id>4f80c6c1825a91cecf3b3bd19c824e768d98fe48</id>
<content type='text'>
commit 23adbe12ef7d3d4195e80800ab36b37bee28cd03 upstream.

The kernel has no concept of capabilities with respect to inodes; inodes
exist independently of namespaces.  For example, inode_capable(inode,
CAP_LINUX_IMMUTABLE) would be nonsense.

This patch changes inode_capable to check for uid and gid mappings and
renames it to capable_wrt_inode_uidgid, which should make it more
obvious what it does.

Fixes CVE-2014-4014.

Cc: Theodore Ts'o &lt;tytso@mit.edu&gt;
Cc: Serge Hallyn &lt;serge.hallyn@ubuntu.com&gt;
Cc: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.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 23adbe12ef7d3d4195e80800ab36b37bee28cd03 upstream.

The kernel has no concept of capabilities with respect to inodes; inodes
exist independently of namespaces.  For example, inode_capable(inode,
CAP_LINUX_IMMUTABLE) would be nonsense.

This patch changes inode_capable to check for uid and gid mappings and
renames it to capable_wrt_inode_uidgid, which should make it more
obvious what it does.

Fixes CVE-2014-4014.

Cc: Theodore Ts'o &lt;tytso@mit.edu&gt;
Cc: Serge Hallyn &lt;serge.hallyn@ubuntu.com&gt;
Cc: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>perf: Drop sample rate when sampling is too slow</title>
<updated>2014-06-11T19:03:26+00:00</updated>
<author>
<name>Dave Hansen</name>
<email>dave.hansen@linux.intel.com</email>
</author>
<published>2013-06-21T15:51:36+00:00</published>
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commit 14c63f17b1fde5a575a28e96547a22b451c71fb5 upstream.

This patch keeps track of how long perf's NMI handler is taking,
and also calculates how many samples perf can take a second.  If
the sample length times the expected max number of samples
exceeds a configurable threshold, it drops the sample rate.

This way, we don't have a runaway sampling process eating up the
CPU.

This patch can tend to drop the sample rate down to level where
perf doesn't work very well.  *BUT* the alternative is that my
system hangs because it spends all of its time handling NMIs.

I'll take a busted performance tool over an entire system that's
busted and undebuggable any day.

BTW, my suspicion is that there's still an underlying bug here.
Using the HPET instead of the TSC is definitely a contributing
factor, but I suspect there are some other things going on.
But, I can't go dig down on a bug like that with my machine
hanging all the time.

Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen &lt;dave@sr71.net&gt;
[ Prettified it a bit. ]
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Weng Meiling &lt;wengmeiling.weng@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit 14c63f17b1fde5a575a28e96547a22b451c71fb5 upstream.

This patch keeps track of how long perf's NMI handler is taking,
and also calculates how many samples perf can take a second.  If
the sample length times the expected max number of samples
exceeds a configurable threshold, it drops the sample rate.

This way, we don't have a runaway sampling process eating up the
CPU.

This patch can tend to drop the sample rate down to level where
perf doesn't work very well.  *BUT* the alternative is that my
system hangs because it spends all of its time handling NMIs.

I'll take a busted performance tool over an entire system that's
busted and undebuggable any day.

BTW, my suspicion is that there's still an underlying bug here.
Using the HPET instead of the TSC is definitely a contributing
factor, but I suspect there are some other things going on.
But, I can't go dig down on a bug like that with my machine
hanging all the time.

Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen &lt;dave@sr71.net&gt;
[ Prettified it a bit. ]
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Weng Meiling &lt;wengmeiling.weng@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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