<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include, branch v5.10.95</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>net_sched: restore "mpu xxx" handling</title>
<updated>2022-01-27T09:54:35+00:00</updated>
<author>
<name>Kevin Bracey</name>
<email>kevin@bracey.fi</email>
</author>
<published>2022-01-12T17:02:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6973b38b9dbacda311c7663a9c297fa95033687a'/>
<id>6973b38b9dbacda311c7663a9c297fa95033687a</id>
<content type='text'>
commit fb80445c438c78b40b547d12b8d56596ce4ccfeb upstream.

commit 56b765b79e9a ("htb: improved accuracy at high rates") broke
"overhead X", "linklayer atm" and "mpu X" attributes.

"overhead X" and "linklayer atm" have already been fixed. This restores
the "mpu X" handling, as might be used by DOCSIS or Ethernet shaping:

    tc class add ... htb rate X overhead 4 mpu 64

The code being fixed is used by htb, tbf and act_police. Cake has its
own mpu handling. qdisc_calculate_pkt_len still uses the size table
containing values adjusted for mpu by user space.

iproute2 tc has always passed mpu into the kernel via a tc_ratespec
structure, but the kernel never directly acted on it, merely stored it
so that it could be read back by `tc class show`.

Rather, tc would generate length-to-time tables that included the mpu
(and linklayer) in their construction, and the kernel used those tables.

Since v3.7, the tables were no longer used. Along with "mpu", this also
broke "overhead" and "linklayer" which were fixed in 01cb71d2d47b
("net_sched: restore "overhead xxx" handling", v3.10) and 8a8e3d84b171
("net_sched: restore "linklayer atm" handling", v3.11).

"overhead" was fixed by simply restoring use of tc_ratespec::overhead -
this had originally been used by the kernel but was initially omitted
from the new non-table-based calculations.

"linklayer" had been handled in the table like "mpu", but the mode was
not originally passed in tc_ratespec. The new implementation was made to
handle it by getting new versions of tc to pass the mode in an extended
tc_ratespec, and for older versions of tc the table contents were analysed
at load time to deduce linklayer.

As "mpu" has always been given to the kernel in tc_ratespec,
accompanying the mpu-based table, we can restore system functionality
with no userspace change by making the kernel act on the tc_ratespec
value.

Fixes: 56b765b79e9a ("htb: improved accuracy at high rates")
Signed-off-by: Kevin Bracey &lt;kevin@bracey.fi&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Jiri Pirko &lt;jiri@resnulli.us&gt;
Cc: Vimalkumar &lt;j.vimal@gmail.com&gt;
Link: https://lore.kernel.org/r/20220112170210.1014351-1-kevin@bracey.fi
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.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 fb80445c438c78b40b547d12b8d56596ce4ccfeb upstream.

commit 56b765b79e9a ("htb: improved accuracy at high rates") broke
"overhead X", "linklayer atm" and "mpu X" attributes.

"overhead X" and "linklayer atm" have already been fixed. This restores
the "mpu X" handling, as might be used by DOCSIS or Ethernet shaping:

    tc class add ... htb rate X overhead 4 mpu 64

The code being fixed is used by htb, tbf and act_police. Cake has its
own mpu handling. qdisc_calculate_pkt_len still uses the size table
containing values adjusted for mpu by user space.

iproute2 tc has always passed mpu into the kernel via a tc_ratespec
structure, but the kernel never directly acted on it, merely stored it
so that it could be read back by `tc class show`.

Rather, tc would generate length-to-time tables that included the mpu
(and linklayer) in their construction, and the kernel used those tables.

Since v3.7, the tables were no longer used. Along with "mpu", this also
broke "overhead" and "linklayer" which were fixed in 01cb71d2d47b
("net_sched: restore "overhead xxx" handling", v3.10) and 8a8e3d84b171
("net_sched: restore "linklayer atm" handling", v3.11).

"overhead" was fixed by simply restoring use of tc_ratespec::overhead -
this had originally been used by the kernel but was initially omitted
from the new non-table-based calculations.

"linklayer" had been handled in the table like "mpu", but the mode was
not originally passed in tc_ratespec. The new implementation was made to
handle it by getting new versions of tc to pass the mode in an extended
tc_ratespec, and for older versions of tc the table contents were analysed
at load time to deduce linklayer.

As "mpu" has always been given to the kernel in tc_ratespec,
accompanying the mpu-based table, we can restore system functionality
with no userspace change by making the kernel act on the tc_ratespec
value.

Fixes: 56b765b79e9a ("htb: improved accuracy at high rates")
Signed-off-by: Kevin Bracey &lt;kevin@bracey.fi&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Jiri Pirko &lt;jiri@resnulli.us&gt;
Cc: Vimalkumar &lt;j.vimal@gmail.com&gt;
Link: https://lore.kernel.org/r/20220112170210.1014351-1-kevin@bracey.fi
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>inet: frags: annotate races around fqdir-&gt;dead and fqdir-&gt;high_thresh</title>
<updated>2022-01-27T09:54:33+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-01-13T09:22:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=edc09548ffc52433ed25ef4a829e664e353f615d'/>
<id>edc09548ffc52433ed25ef4a829e664e353f615d</id>
<content type='text'>
commit 91341fa0003befd097e190ec2a4bf63ad957c49a upstream.

Both fields can be read/written without synchronization,
add proper accessors and documentation.

Fixes: d5dd88794a13 ("inet: fix various use-after-free in defrags units")
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>
commit 91341fa0003befd097e190ec2a4bf63ad957c49a upstream.

Both fields can be read/written without synchronization,
add proper accessors and documentation.

Fixes: d5dd88794a13 ("inet: fix various use-after-free in defrags units")
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>ACPICA: actypes.h: Expand the ACPI_ACCESS_ definitions</title>
<updated>2022-01-27T09:54:18+00:00</updated>
<author>
<name>Mark Langsdorf</name>
<email>mlangsdo@redhat.com</email>
</author>
<published>2021-12-22T15:57:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fcfd8282c5d2fa335455a33c18d4426c58b80f72'/>
<id>fcfd8282c5d2fa335455a33c18d4426c58b80f72</id>
<content type='text'>
[ Upstream commit f81bdeaf816142e0729eea0cc84c395ec9673151 ]

ACPICA commit bc02c76d518135531483dfc276ed28b7ee632ce1

The current ACPI_ACCESS_*_WIDTH defines do not provide a way to
test that size is small enough to not cause an overflow when
applied to a 32-bit integer.

Rather than adding more magic numbers, add ACPI_ACCESS_*_SHIFT,
ACPI_ACCESS_*_MAX, and ACPI_ACCESS_*_DEFAULT #defines and
redefine ACPI_ACCESS_*_WIDTH in terms of the new #defines.

This was inititally reported on Linux where a size of 102 in
ACPI_ACCESS_BIT_WIDTH caused an overflow error in the SPCR
initialization code.

Link: https://github.com/acpica/acpica/commit/bc02c76d
Signed-off-by: Mark Langsdorf &lt;mlangsdo@redhat.com&gt;
Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit f81bdeaf816142e0729eea0cc84c395ec9673151 ]

ACPICA commit bc02c76d518135531483dfc276ed28b7ee632ce1

The current ACPI_ACCESS_*_WIDTH defines do not provide a way to
test that size is small enough to not cause an overflow when
applied to a 32-bit integer.

Rather than adding more magic numbers, add ACPI_ACCESS_*_SHIFT,
ACPI_ACCESS_*_MAX, and ACPI_ACCESS_*_DEFAULT #defines and
redefine ACPI_ACCESS_*_WIDTH in terms of the new #defines.

This was inititally reported on Linux where a size of 102 in
ACPI_ACCESS_BIT_WIDTH caused an overflow error in the SPCR
initialization code.

Link: https://github.com/acpica/acpica/commit/bc02c76d
Signed-off-by: Mark Langsdorf &lt;mlangsdo@redhat.com&gt;
Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xfrm: rate limit SA mapping change message to user space</title>
<updated>2022-01-27T09:54:18+00:00</updated>
<author>
<name>Antony Antony</name>
<email>antony.antony@secunet.com</email>
</author>
<published>2021-12-22T13:11:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a0b13335a342c9083640ba0ea6fe7c8d8076cae7'/>
<id>a0b13335a342c9083640ba0ea6fe7c8d8076cae7</id>
<content type='text'>
[ Upstream commit 4e484b3e969b52effd95c17f7a86f39208b2ccf4 ]

Kernel generates mapping change message, XFRM_MSG_MAPPING,
when a source port chage is detected on a input state with UDP
encapsulation set.  Kernel generates a message for each IPsec packet
with new source port.  For a high speed flow per packet mapping change
message can be excessive, and can overload the user space listener.

Introduce rate limiting for XFRM_MSG_MAPPING message to the user space.

The rate limiting is configurable via netlink, when adding a new SA or
updating it. Use the new attribute XFRMA_MTIMER_THRESH in seconds.

v1-&gt;v2 change:
	update xfrm_sa_len()

v2-&gt;v3 changes:
	use u32 insted unsigned long to reduce size of struct xfrm_state
	fix xfrm_ompat size Reported-by: kernel test robot &lt;lkp@intel.com&gt;
	accept XFRM_MSG_MAPPING only when XFRMA_ENCAP is present

Co-developed-by: Thomas Egerer &lt;thomas.egerer@secunet.com&gt;
Signed-off-by: Thomas Egerer &lt;thomas.egerer@secunet.com&gt;
Signed-off-by: Antony Antony &lt;antony.antony@secunet.com&gt;
Signed-off-by: Steffen Klassert &lt;steffen.klassert@secunet.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4e484b3e969b52effd95c17f7a86f39208b2ccf4 ]

Kernel generates mapping change message, XFRM_MSG_MAPPING,
when a source port chage is detected on a input state with UDP
encapsulation set.  Kernel generates a message for each IPsec packet
with new source port.  For a high speed flow per packet mapping change
message can be excessive, and can overload the user space listener.

Introduce rate limiting for XFRM_MSG_MAPPING message to the user space.

The rate limiting is configurable via netlink, when adding a new SA or
updating it. Use the new attribute XFRMA_MTIMER_THRESH in seconds.

v1-&gt;v2 change:
	update xfrm_sa_len()

v2-&gt;v3 changes:
	use u32 insted unsigned long to reduce size of struct xfrm_state
	fix xfrm_ompat size Reported-by: kernel test robot &lt;lkp@intel.com&gt;
	accept XFRM_MSG_MAPPING only when XFRMA_ENCAP is present

Co-developed-by: Thomas Egerer &lt;thomas.egerer@secunet.com&gt;
Signed-off-by: Thomas Egerer &lt;thomas.egerer@secunet.com&gt;
Signed-off-by: Antony Antony &lt;antony.antony@secunet.com&gt;
Signed-off-by: Steffen Klassert &lt;steffen.klassert@secunet.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: runtime: Add safety net to supplier device release</title>
<updated>2022-01-27T09:54:17+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-12-10T16:10:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=37b25de3af10a3082f9ef5888de0f8602c5dcadf'/>
<id>37b25de3af10a3082f9ef5888de0f8602c5dcadf</id>
<content type='text'>
[ Upstream commit d1579e61192e0e686faa4208500ef4c3b529b16c ]

Because refcount_dec_not_one() returns true if the target refcount
becomes saturated, it is generally unsafe to use its return value as
a loop termination condition, but that is what happens when a device
link's supplier device is released during runtime PM suspend
operations and on device link removal.

To address this, introduce pm_runtime_release_supplier() to be used
in the above cases which will check the supplier device's runtime
PM usage counter in addition to the refcount_dec_not_one() return
value, so the loop can be terminated in case the rpm_active refcount
value becomes invalid, and update the code in question to use it as
appropriate.

This change is not expected to have any visible functional impact.

Reported-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d1579e61192e0e686faa4208500ef4c3b529b16c ]

Because refcount_dec_not_one() returns true if the target refcount
becomes saturated, it is generally unsafe to use its return value as
a loop termination condition, but that is what happens when a device
link's supplier device is released during runtime PM suspend
operations and on device link removal.

To address this, introduce pm_runtime_release_supplier() to be used
in the above cases which will check the supplier device's runtime
PM usage counter in addition to the refcount_dec_not_one() return
value, so the loop can be terminated in case the rpm_active refcount
value becomes invalid, and update the code in question to use it as
appropriate.

This change is not expected to have any visible functional impact.

Reported-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>HID: quirks: Allow inverting the absolute X/Y values</title>
<updated>2022-01-27T09:54:16+00:00</updated>
<author>
<name>Alistair Francis</name>
<email>alistair@alistair23.me</email>
</author>
<published>2021-12-08T12:40:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d698e024be2ea5bb4f441e0b07f82def42d6a168'/>
<id>d698e024be2ea5bb4f441e0b07f82def42d6a168</id>
<content type='text'>
[ Upstream commit fd8d135b2c5e88662f2729e034913f183455a667 ]

Add a HID_QUIRK_X_INVERT/HID_QUIRK_Y_INVERT quirk that can be used
to invert the X/Y values.

Signed-off-by: Alistair Francis &lt;alistair@alistair23.me&gt;
[bentiss: silence checkpatch warning]
Signed-off-by: Benjamin Tissoires &lt;benjamin.tissoires@redhat.com&gt;
Link: https://lore.kernel.org/r/20211208124045.61815-2-alistair@alistair23.me
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit fd8d135b2c5e88662f2729e034913f183455a667 ]

Add a HID_QUIRK_X_INVERT/HID_QUIRK_Y_INVERT quirk that can be used
to invert the X/Y values.

Signed-off-by: Alistair Francis &lt;alistair@alistair23.me&gt;
[bentiss: silence checkpatch warning]
Signed-off-by: Benjamin Tissoires &lt;benjamin.tissoires@redhat.com&gt;
Link: https://lore.kernel.org/r/20211208124045.61815-2-alistair@alistair23.me
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: Change acpi_device_always_present() into acpi_device_override_status()</title>
<updated>2022-01-27T09:54:13+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2021-11-22T17:05:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cda755506df4c73b23c2f37943350a435bf52f44'/>
<id>cda755506df4c73b23c2f37943350a435bf52f44</id>
<content type='text'>
[ Upstream commit 1a68b346a2c9969c05e80a3b99a9ab160b5655c0 ]

Currently, acpi_bus_get_status() calls acpi_device_always_present() to
allow platform quirks to override the _STA return to report that a
device is present (status = ACPI_STA_DEFAULT) independent of the _STA
return.

In some cases it might also be useful to have the opposite functionality
and have a platform quirk which marks a device as not present (status = 0)
to work around ACPI table bugs.

Change acpi_device_always_present() into a more generic
acpi_device_override_status() function to allow this.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 1a68b346a2c9969c05e80a3b99a9ab160b5655c0 ]

Currently, acpi_bus_get_status() calls acpi_device_always_present() to
allow platform quirks to override the _STA return to report that a
device is present (status = ACPI_STA_DEFAULT) independent of the _STA
return.

In some cases it might also be useful to have the opposite functionality
and have a platform quirk which marks a device as not present (status = 0)
to work around ACPI table bugs.

Change acpi_device_always_present() into a more generic
acpi_device_override_status() function to allow this.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>scsi: block: pm: Always set request queue runtime active in blk_post_runtime_resume()</title>
<updated>2022-01-27T09:54:08+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2021-12-20T11:21:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d781f4cd8c71fe2b42cf5784860fc1c68644b44d'/>
<id>d781f4cd8c71fe2b42cf5784860fc1c68644b44d</id>
<content type='text'>
[ Upstream commit 6e1fcab00a23f7fe9f4fe9704905a790efa1eeab ]

John Garry reported a deadlock that occurs when trying to access a
runtime-suspended SATA device.  For obscure reasons, the rescan procedure
causes the link to be hard-reset, which disconnects the device.

The rescan tries to carry out a runtime resume when accessing the device.
scsi_rescan_device() holds the SCSI device lock and won't release it until
it can put commands onto the device's block queue.  This can't happen until
the queue is successfully runtime-resumed or the device is unregistered.
But the runtime resume fails because the device is disconnected, and
__scsi_remove_device() can't do the unregistration because it can't get the
device lock.

The best way to resolve this deadlock appears to be to allow the block
queue to start running again even after an unsuccessful runtime resume.
The idea is that the driver or the SCSI error handler will need to be able
to use the queue to resolve the runtime resume failure.

This patch removes the err argument to blk_post_runtime_resume() and makes
the routine act as though the resume was successful always.  This fixes the
deadlock.

Link: https://lore.kernel.org/r/1639999298-244569-4-git-send-email-chenxiang66@hisilicon.com
Fixes: e27829dc92e5 ("scsi: serialize -&gt;rescan against -&gt;remove")
Reported-and-tested-by: John Garry &lt;john.garry@huawei.com&gt;
Reviewed-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Xiang Chen &lt;chenxiang66@hisilicon.com&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6e1fcab00a23f7fe9f4fe9704905a790efa1eeab ]

John Garry reported a deadlock that occurs when trying to access a
runtime-suspended SATA device.  For obscure reasons, the rescan procedure
causes the link to be hard-reset, which disconnects the device.

The rescan tries to carry out a runtime resume when accessing the device.
scsi_rescan_device() holds the SCSI device lock and won't release it until
it can put commands onto the device's block queue.  This can't happen until
the queue is successfully runtime-resumed or the device is unregistered.
But the runtime resume fails because the device is disconnected, and
__scsi_remove_device() can't do the unregistration because it can't get the
device lock.

The best way to resolve this deadlock appears to be to allow the block
queue to start running again even after an unsuccessful runtime resume.
The idea is that the driver or the SCSI error handler will need to be able
to use the queue to resolve the runtime resume failure.

This patch removes the err argument to blk_post_runtime_resume() and makes
the routine act as though the resume was successful always.  This fixes the
deadlock.

Link: https://lore.kernel.org/r/1639999298-244569-4-git-send-email-chenxiang66@hisilicon.com
Fixes: e27829dc92e5 ("scsi: serialize -&gt;rescan against -&gt;remove")
Reported-and-tested-by: John Garry &lt;john.garry@huawei.com&gt;
Reviewed-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Xiang Chen &lt;chenxiang66@hisilicon.com&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource: Reduce clocksource-skew threshold</title>
<updated>2022-01-27T09:54:05+00:00</updated>
<author>
<name>Paul E. McKenney</name>
<email>paulmck@kernel.org</email>
</author>
<published>2021-05-27T19:01:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cacc6c30e3eb7c452132ee5b273e248d2f263323'/>
<id>cacc6c30e3eb7c452132ee5b273e248d2f263323</id>
<content type='text'>
[ Upstream commit 2e27e793e280ff12cb5c202a1214c08b0d3a0f26 ]

Currently, WATCHDOG_THRESHOLD is set to detect a 62.5-millisecond skew in
a 500-millisecond WATCHDOG_INTERVAL.  This requires that clocks be skewed
by more than 12.5% in order to be marked unstable.  Except that a clock
that is skewed by that much is probably destroying unsuspecting software
right and left.  And given that there are now checks for false-positive
skews due to delays between reading the two clocks, it should be possible
to greatly decrease WATCHDOG_THRESHOLD, at least for fine-grained clocks
such as TSC.

Therefore, add a new uncertainty_margin field to the clocksource structure
that contains the maximum uncertainty in nanoseconds for the corresponding
clock.  This field may be initialized manually, as it is for
clocksource_tsc_early and clocksource_jiffies, which is copied to
refined_jiffies.  If the field is not initialized manually, it will be
computed at clock-registry time as the period of the clock in question
based on the scale and freq parameters to __clocksource_update_freq_scale()
function.  If either of those two parameters are zero, the
tens-of-milliseconds WATCHDOG_THRESHOLD is used as a cowardly alternative
to dividing by zero.  No matter how the uncertainty_margin field is
calculated, it is bounded below by twice WATCHDOG_MAX_SKEW, that is, by 100
microseconds.

Note that manually initialized uncertainty_margin fields are not adjusted,
but there is a WARN_ON_ONCE() that triggers if any such field is less than
twice WATCHDOG_MAX_SKEW.  This WARN_ON_ONCE() is intended to discourage
production use of the one-nanosecond uncertainty_margin values that are
used to test the clock-skew code itself.

The actual clock-skew check uses the sum of the uncertainty_margin fields
of the two clocksource structures being compared.  Integer overflow is
avoided because the largest computed value of the uncertainty_margin
fields is one billion (10^9), and double that value fits into an
unsigned int.  However, if someone manually specifies (say) UINT_MAX,
they will get what they deserve.

Note that the refined_jiffies uncertainty_margin field is initialized to
TICK_NSEC, which means that skew checks involving this clocksource will
be sufficently forgiving.  In a similar vein, the clocksource_tsc_early
uncertainty_margin field is initialized to 32*NSEC_PER_MSEC, which
replicates the current behavior and allows custom setting if needed
in order to address the rare skews detected for this clocksource in
current mainline.

Suggested-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Feng Tang &lt;feng.tang@intel.com&gt;
Link: https://lore.kernel.org/r/20210527190124.440372-4-paulmck@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2e27e793e280ff12cb5c202a1214c08b0d3a0f26 ]

Currently, WATCHDOG_THRESHOLD is set to detect a 62.5-millisecond skew in
a 500-millisecond WATCHDOG_INTERVAL.  This requires that clocks be skewed
by more than 12.5% in order to be marked unstable.  Except that a clock
that is skewed by that much is probably destroying unsuspecting software
right and left.  And given that there are now checks for false-positive
skews due to delays between reading the two clocks, it should be possible
to greatly decrease WATCHDOG_THRESHOLD, at least for fine-grained clocks
such as TSC.

Therefore, add a new uncertainty_margin field to the clocksource structure
that contains the maximum uncertainty in nanoseconds for the corresponding
clock.  This field may be initialized manually, as it is for
clocksource_tsc_early and clocksource_jiffies, which is copied to
refined_jiffies.  If the field is not initialized manually, it will be
computed at clock-registry time as the period of the clock in question
based on the scale and freq parameters to __clocksource_update_freq_scale()
function.  If either of those two parameters are zero, the
tens-of-milliseconds WATCHDOG_THRESHOLD is used as a cowardly alternative
to dividing by zero.  No matter how the uncertainty_margin field is
calculated, it is bounded below by twice WATCHDOG_MAX_SKEW, that is, by 100
microseconds.

Note that manually initialized uncertainty_margin fields are not adjusted,
but there is a WARN_ON_ONCE() that triggers if any such field is less than
twice WATCHDOG_MAX_SKEW.  This WARN_ON_ONCE() is intended to discourage
production use of the one-nanosecond uncertainty_margin values that are
used to test the clock-skew code itself.

The actual clock-skew check uses the sum of the uncertainty_margin fields
of the two clocksource structures being compared.  Integer overflow is
avoided because the largest computed value of the uncertainty_margin
fields is one billion (10^9), and double that value fits into an
unsigned int.  However, if someone manually specifies (say) UINT_MAX,
they will get what they deserve.

Note that the refined_jiffies uncertainty_margin field is initialized to
TICK_NSEC, which means that skew checks involving this clocksource will
be sufficently forgiving.  In a similar vein, the clocksource_tsc_early
uncertainty_margin field is initialized to 32*NSEC_PER_MSEC, which
replicates the current behavior and allows custom setting if needed
in order to address the rare skews detected for this clocksource in
current mainline.

Suggested-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Feng Tang &lt;feng.tang@intel.com&gt;
Link: https://lore.kernel.org/r/20210527190124.440372-4-paulmck@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Disallow BPF_LOG_KERNEL log level for bpf(BPF_BTF_LOAD)</title>
<updated>2022-01-27T09:53:54+00:00</updated>
<author>
<name>Hou Tao</name>
<email>houtao1@huawei.com</email>
</author>
<published>2021-12-03T05:30:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=924886fa2246d24d0f0f80096300f607f1b7a829'/>
<id>924886fa2246d24d0f0f80096300f607f1b7a829</id>
<content type='text'>
[ Upstream commit 866de407444398bc8140ea70de1dba5f91cc34ac ]

BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load()
to set log level as BPF_LOG_KERNEL. The same checking has already
been done in bpf_check(), so factor out a helper to check the
validity of log attributes and use it in both places.

Fixes: 8580ac9404f6 ("bpf: Process in-kernel BTF")
Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Yonghong Song &lt;yhs@fb.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Link: https://lore.kernel.org/bpf/20211203053001.740945-1-houtao1@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 866de407444398bc8140ea70de1dba5f91cc34ac ]

BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load()
to set log level as BPF_LOG_KERNEL. The same checking has already
been done in bpf_check(), so factor out a helper to check the
validity of log attributes and use it in both places.

Fixes: 8580ac9404f6 ("bpf: Process in-kernel BTF")
Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Yonghong Song &lt;yhs@fb.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Link: https://lore.kernel.org/bpf/20211203053001.740945-1-houtao1@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
