<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git, branch v5.13.8</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>Linux 5.13.8</title>
<updated>2021-08-04T10:47:57+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2021-08-04T10:47:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=3cfdd7252e00ecf3f3dc9508525acf1e67b7d343'/>
<id>3cfdd7252e00ecf3f3dc9508525acf1e67b7d343</id>
<content type='text'>
Link: https://lore.kernel.org/r/20210802134344.028226640@linuxfoundation.org
Tested-by: Justin M. Forbes &lt;jforbes@fedoraproject.org&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Tested-by: Linux Kernel Functional Testing &lt;lkft@linaro.org&gt;
Tested-by: Fox Chen &lt;foxhlchen@gmail.com&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>
Link: https://lore.kernel.org/r/20210802134344.028226640@linuxfoundation.org
Tested-by: Justin M. Forbes &lt;jforbes@fedoraproject.org&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Tested-by: Linux Kernel Functional Testing &lt;lkft@linaro.org&gt;
Tested-by: Fox Chen &lt;foxhlchen@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>octeontx2-af: Remove unnecessary devm_kfree</title>
<updated>2021-08-04T10:47:57+00:00</updated>
<author>
<name>Sunil Goutham</name>
<email>sgoutham@marvell.com</email>
</author>
<published>2021-07-22T12:45:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=d92d15c288413661e43542f0c2ac478e9d8e5de6'/>
<id>d92d15c288413661e43542f0c2ac478e9d8e5de6</id>
<content type='text'>
commit d72e91efcae12f2f24ced984d00d60517c677857 upstream.

Remove devm_kfree of memory where VLAN entry to RVU PF mapping
info is saved. This will be freed anyway at driver exit.
Having this could result in warning from devm_kfree() if
the memory is not allocated due to errors in rvu_nix_block_init()
before nix_setup_txvlan().

Fixes: 9a946def264d ("octeontx2-af: Modify nix_vtag_cfg mailbox to support TX VTAG entries")
Signed-off-by: Sunil Goutham &lt;sgoutham@marvell.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 d72e91efcae12f2f24ced984d00d60517c677857 upstream.

Remove devm_kfree of memory where VLAN entry to RVU PF mapping
info is saved. This will be freed anyway at driver exit.
Having this could result in warning from devm_kfree() if
the memory is not allocated due to errors in rvu_nix_block_init()
before nix_setup_txvlan().

Fixes: 9a946def264d ("octeontx2-af: Modify nix_vtag_cfg mailbox to support TX VTAG entries")
Signed-off-by: Sunil Goutham &lt;sgoutham@marvell.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>perf pmu: Fix alias matching</title>
<updated>2021-08-04T10:47:57+00:00</updated>
<author>
<name>John Garry</name>
<email>john.garry@huawei.com</email>
</author>
<published>2021-07-20T15:10:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=187463c4a262fb010d6b240c09cedfe780aac580'/>
<id>187463c4a262fb010d6b240c09cedfe780aac580</id>
<content type='text'>
commit c07d5c9226980ca5ae21c6a2714baa95be2ce164 upstream.

Commit c47a5599eda324ba ("perf tools: Fix pattern matching for same
substring in different PMU type"), may have fixed some alias matching,
but has broken some others.

Firstly it cannot handle the simple scenario of PMU name in form
pmu_name{digits} - it can only handle pmu_name_{digits}.

Secondly it cannot handle more complex matching in the case where we
have multiple tokens. In this scenario, the code failed to realise that
we may examine multiple substrings in the PMU name.

Fix in two ways:

- Change perf_pmu__valid_suffix() to accept a PMU name without '_' in the
  suffix

- Only pay attention to perf_pmu__valid_suffix() for the final token

Also add const qualifiers as necessary to avoid casting.

Fixes: c47a5599eda324ba ("perf tools: Fix pattern matching for same substring in different PMU type")
Signed-off-by: John Garry &lt;john.garry@huawei.com&gt;
Tested-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/1626793819-79090-1-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&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 c07d5c9226980ca5ae21c6a2714baa95be2ce164 upstream.

Commit c47a5599eda324ba ("perf tools: Fix pattern matching for same
substring in different PMU type"), may have fixed some alias matching,
but has broken some others.

Firstly it cannot handle the simple scenario of PMU name in form
pmu_name{digits} - it can only handle pmu_name_{digits}.

Secondly it cannot handle more complex matching in the case where we
have multiple tokens. In this scenario, the code failed to realise that
we may examine multiple substrings in the PMU name.

Fix in two ways:

- Change perf_pmu__valid_suffix() to accept a PMU name without '_' in the
  suffix

- Only pay attention to perf_pmu__valid_suffix() for the final token

Also add const qualifiers as necessary to avoid casting.

Fixes: c47a5599eda324ba ("perf tools: Fix pattern matching for same substring in different PMU type")
Signed-off-by: John Garry &lt;john.garry@huawei.com&gt;
Tested-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/1626793819-79090-1-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: j1939: j1939_session_deactivate(): clarify lifetime of session object</title>
<updated>2021-08-04T10:47:57+00:00</updated>
<author>
<name>Oleksij Rempel</name>
<email>o.rempel@pengutronix.de</email>
</author>
<published>2021-07-14T11:16:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=5e1fc537c1be332aef9621ca9146aeb3ba59522f'/>
<id>5e1fc537c1be332aef9621ca9146aeb3ba59522f</id>
<content type='text'>
commit 0c71437dd50dd687c15d8ca80b3b68f10bb21d63 upstream.

The j1939_session_deactivate() is decrementing the session ref-count and
potentially can free() the session. This would cause use-after-free
situation.

However, the code calling j1939_session_deactivate() does always hold
another reference to the session, so that it would not be free()ed in
this code path.

This patch adds a comment to make this clear and a WARN_ON, to ensure
that future changes will not violate this requirement. Further this
patch avoids dereferencing the session pointer as a precaution to avoid
use-after-free if the session is actually free()ed.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Link: https://lore.kernel.org/r/20210714111602.24021-1-o.rempel@pengutronix.de
Reported-by: Xiaochen Zou &lt;xzou017@ucr.edu&gt;
Signed-off-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.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 0c71437dd50dd687c15d8ca80b3b68f10bb21d63 upstream.

The j1939_session_deactivate() is decrementing the session ref-count and
potentially can free() the session. This would cause use-after-free
situation.

However, the code calling j1939_session_deactivate() does always hold
another reference to the session, so that it would not be free()ed in
this code path.

This patch adds a comment to make this clear and a WARN_ON, to ensure
that future changes will not violate this requirement. Further this
patch avoids dereferencing the session pointer as a precaution to avoid
use-after-free if the session is actually free()ed.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Link: https://lore.kernel.org/r/20210714111602.24021-1-o.rempel@pengutronix.de
Reported-by: Xiaochen Zou &lt;xzou017@ucr.edu&gt;
Signed-off-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i40e: Add additional info to PHY type error</title>
<updated>2021-08-04T10:47:57+00:00</updated>
<author>
<name>Lukasz Cieplicki</name>
<email>lukaszx.cieplicki@intel.com</email>
</author>
<published>2021-05-31T16:55:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=f27deb33bbdbc9d990a3ce08c334c7747d3216f2'/>
<id>f27deb33bbdbc9d990a3ce08c334c7747d3216f2</id>
<content type='text'>
commit dc614c46178b0b89bde86ac54fc687a28580d2b7 upstream.

In case of PHY type error occurs, the message was too generic.
Add additional info to PHY type error indicating that it can be
wrong cable connected.

Fixes: 124ed15bf126 ("i40e: Add dual speed module support")
Signed-off-by: Lukasz Cieplicki &lt;lukaszx.cieplicki@intel.com&gt;
Signed-off-by: Michal Maloszewski &lt;michal.maloszewski@intel.com&gt;
Tested-by: Tony Brelinski &lt;tonyx.brelinski@intel.com&gt;
Signed-off-by: Tony Nguyen &lt;anthony.l.nguyen@intel.com&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 dc614c46178b0b89bde86ac54fc687a28580d2b7 upstream.

In case of PHY type error occurs, the message was too generic.
Add additional info to PHY type error indicating that it can be
wrong cable connected.

Fixes: 124ed15bf126 ("i40e: Add dual speed module support")
Signed-off-by: Lukasz Cieplicki &lt;lukaszx.cieplicki@intel.com&gt;
Signed-off-by: Michal Maloszewski &lt;michal.maloszewski@intel.com&gt;
Tested-by: Tony Brelinski &lt;tonyx.brelinski@intel.com&gt;
Signed-off-by: Tony Nguyen &lt;anthony.l.nguyen@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>io_uring: fix race in unified task_work running</title>
<updated>2021-08-04T10:47:57+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2021-07-26T16:42:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=e95d994d2f8fcff9549433fdcd569300fa3dd123'/>
<id>e95d994d2f8fcff9549433fdcd569300fa3dd123</id>
<content type='text'>
commit 110aa25c3ce417a44e35990cf8ed22383277933a upstream.

We use a bit to manage if we need to add the shared task_work, but
a list + lock for the pending work. Before aborting a current run
of the task_work we check if the list is empty, but we do so without
grabbing the lock that protects it. This can lead to races where
we think we have nothing left to run, where in practice we could be
racing with a task adding new work to the list. If we do hit that
race condition, we could be left with work items that need processing,
but the shared task_work is not active.

Ensure that we grab the lock before checking if the list is empty,
so we know if it's safe to exit the run or not.

Link: https://lore.kernel.org/io-uring/c6bd5987-e9ae-cd02-49d0-1b3ac1ef65b1@tnonline.net/
Cc: stable@vger.kernel.org # 5.11+
Reported-by: Forza &lt;forza@tnonline.net&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&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 110aa25c3ce417a44e35990cf8ed22383277933a upstream.

We use a bit to manage if we need to add the shared task_work, but
a list + lock for the pending work. Before aborting a current run
of the task_work we check if the list is empty, but we do so without
grabbing the lock that protects it. This can lead to races where
we think we have nothing left to run, where in practice we could be
racing with a task adding new work to the list. If we do hit that
race condition, we could be left with work items that need processing,
but the shared task_work is not active.

Ensure that we grab the lock before checking if the list is empty,
so we know if it's safe to exit the run or not.

Link: https://lore.kernel.org/io-uring/c6bd5987-e9ae-cd02-49d0-1b3ac1ef65b1@tnonline.net/
Cc: stable@vger.kernel.org # 5.11+
Reported-by: Forza &lt;forza@tnonline.net&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "perf map: Fix dso-&gt;nsinfo refcounting"</title>
<updated>2021-08-04T10:47:56+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-07-30T21:26:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ee6d50cb1c239e15b6b6ac486fc6ed844955d441'/>
<id>ee6d50cb1c239e15b6b6ac486fc6ed844955d441</id>
<content type='text'>
commit 9bac1bd6e6d36459087a728a968e79e37ebcea1a upstream.

This makes 'perf top' abort in some cases, and the right fix will
involve surgery that is too much to do at this stage, so revert for now
and fix it in the next merge window.

This reverts commit 2d6b74baa7147251c30a46c4996e8cc224aa2dc5.

Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Krister Johansen &lt;kjlx@templeofstupid.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&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 9bac1bd6e6d36459087a728a968e79e37ebcea1a upstream.

This makes 'perf top' abort in some cases, and the right fix will
involve surgery that is too much to do at this stage, so revert for now
and fix it in the next merge window.

This reverts commit 2d6b74baa7147251c30a46c4996e8cc224aa2dc5.

Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Krister Johansen &lt;kjlx@templeofstupid.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/pseries: Fix regression while building external modules</title>
<updated>2021-08-04T10:47:56+00:00</updated>
<author>
<name>Srikar Dronamraju</name>
<email>srikar@linux.vnet.ibm.com</email>
</author>
<published>2021-07-29T06:04:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=9755a447ec42dacef80c201039935dbcb57e88b0'/>
<id>9755a447ec42dacef80c201039935dbcb57e88b0</id>
<content type='text'>
commit 333cf507465fbebb3727f5b53e77538467df312a upstream.

With commit c9f3401313a5 ("powerpc: Always enable queued spinlocks for
64s, disable for others") CONFIG_PPC_QUEUED_SPINLOCKS is always
enabled on ppc64le, external modules that use spinlock APIs are
failing.

  ERROR: modpost: GPL-incompatible module XXX.ko uses GPL-only symbol 'shared_processor'

Before the above commit, modules were able to build without any
issues. Also this problem is not seen on other architectures. This
problem can be workaround if CONFIG_UNINLINE_SPIN_UNLOCK is enabled in
the config. However CONFIG_UNINLINE_SPIN_UNLOCK is not enabled by
default and only enabled in certain conditions like
CONFIG_DEBUG_SPINLOCKS is set in the kernel config.

  #include &lt;linux/module.h&gt;
  spinlock_t spLock;

  static int __init spinlock_test_init(void)
  {
          spin_lock_init(&amp;spLock);
          spin_lock(&amp;spLock);
          spin_unlock(&amp;spLock);
          return 0;
  }

  static void __exit spinlock_test_exit(void)
  {
  	printk("spinlock_test unloaded\n");
  }
  module_init(spinlock_test_init);
  module_exit(spinlock_test_exit);

  MODULE_DESCRIPTION ("spinlock_test");
  MODULE_LICENSE ("non-GPL");
  MODULE_AUTHOR ("Srikar Dronamraju");

Given that spin locks are one of the basic facilities for module code,
this effectively makes it impossible to build/load almost any non GPL
modules on ppc64le.

This was first reported at https://github.com/openzfs/zfs/issues/11172

Currently shared_processor is exported as GPL only symbol.
Fix this for parity with other architectures by exposing
shared_processor to non-GPL modules too.

Fixes: 14c73bd344da ("powerpc/vcpu: Assume dedicated processors as non-preempt")
Cc: stable@vger.kernel.org # v5.5+
Reported-by: marc.c.dionne@gmail.com
Signed-off-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20210729060449.292780-1-srikar@linux.vnet.ibm.com
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 333cf507465fbebb3727f5b53e77538467df312a upstream.

With commit c9f3401313a5 ("powerpc: Always enable queued spinlocks for
64s, disable for others") CONFIG_PPC_QUEUED_SPINLOCKS is always
enabled on ppc64le, external modules that use spinlock APIs are
failing.

  ERROR: modpost: GPL-incompatible module XXX.ko uses GPL-only symbol 'shared_processor'

Before the above commit, modules were able to build without any
issues. Also this problem is not seen on other architectures. This
problem can be workaround if CONFIG_UNINLINE_SPIN_UNLOCK is enabled in
the config. However CONFIG_UNINLINE_SPIN_UNLOCK is not enabled by
default and only enabled in certain conditions like
CONFIG_DEBUG_SPINLOCKS is set in the kernel config.

  #include &lt;linux/module.h&gt;
  spinlock_t spLock;

  static int __init spinlock_test_init(void)
  {
          spin_lock_init(&amp;spLock);
          spin_lock(&amp;spLock);
          spin_unlock(&amp;spLock);
          return 0;
  }

  static void __exit spinlock_test_exit(void)
  {
  	printk("spinlock_test unloaded\n");
  }
  module_init(spinlock_test_init);
  module_exit(spinlock_test_exit);

  MODULE_DESCRIPTION ("spinlock_test");
  MODULE_LICENSE ("non-GPL");
  MODULE_AUTHOR ("Srikar Dronamraju");

Given that spin locks are one of the basic facilities for module code,
this effectively makes it impossible to build/load almost any non GPL
modules on ppc64le.

This was first reported at https://github.com/openzfs/zfs/issues/11172

Currently shared_processor is exported as GPL only symbol.
Fix this for parity with other architectures by exposing
shared_processor to non-GPL modules too.

Fixes: 14c73bd344da ("powerpc/vcpu: Assume dedicated processors as non-preempt")
Cc: stable@vger.kernel.org # v5.5+
Reported-by: marc.c.dionne@gmail.com
Signed-off-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20210729060449.292780-1-srikar@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/vdso: Don't use r30 to avoid breaking Go lang</title>
<updated>2021-08-04T10:47:56+00:00</updated>
<author>
<name>Michael Ellerman</name>
<email>mpe@ellerman.id.au</email>
</author>
<published>2021-07-29T12:56:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c73256979654a8dfd707e26a7abee840f66c4b1d'/>
<id>c73256979654a8dfd707e26a7abee840f66c4b1d</id>
<content type='text'>
commit a88603f4b92ecef9e2359e40bcb99ad399d85dd7 upstream.

The Go runtime uses r30 for some special value called 'g'. It assumes
that value will remain unchanged even when calling VDSO functions.
Although r30 is non-volatile across function calls, the callee is free
to use it, as long as the callee saves the value and restores it before
returning.

It used to be true by accident that the VDSO didn't use r30, because the
VDSO was hand-written asm. When we switched to building the VDSO from C
the compiler started using r30, at least in some builds, leading to
crashes in Go. eg:

  ~/go/src$ ./all.bash
  Building Go cmd/dist using /usr/lib/go-1.16. (go1.16.2 linux/ppc64le)
  Building Go toolchain1 using /usr/lib/go-1.16.
  go build os/exec: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault
  go build reflect: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault
  go tool dist: FAILED: /usr/lib/go-1.16/bin/go install -gcflags=-l -tags=math_big_pure_go compiler_bootstrap bootstrap/cmd/...: exit status 1

There are patches in flight to fix Go[1], but until they are released
and widely deployed we can workaround it in the VDSO by avoiding use of
r30.

Note this only works with GCC, clang does not support -ffixed-rN.

1: https://go-review.googlesource.com/c/go/+/328110

Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.")
Cc: stable@vger.kernel.org # v5.11+
Reported-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Tested-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20210729131244.2595519-1-mpe@ellerman.id.au
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 a88603f4b92ecef9e2359e40bcb99ad399d85dd7 upstream.

The Go runtime uses r30 for some special value called 'g'. It assumes
that value will remain unchanged even when calling VDSO functions.
Although r30 is non-volatile across function calls, the callee is free
to use it, as long as the callee saves the value and restores it before
returning.

It used to be true by accident that the VDSO didn't use r30, because the
VDSO was hand-written asm. When we switched to building the VDSO from C
the compiler started using r30, at least in some builds, leading to
crashes in Go. eg:

  ~/go/src$ ./all.bash
  Building Go cmd/dist using /usr/lib/go-1.16. (go1.16.2 linux/ppc64le)
  Building Go toolchain1 using /usr/lib/go-1.16.
  go build os/exec: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault
  go build reflect: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault
  go tool dist: FAILED: /usr/lib/go-1.16/bin/go install -gcflags=-l -tags=math_big_pure_go compiler_bootstrap bootstrap/cmd/...: exit status 1

There are patches in flight to fix Go[1], but until they are released
and widely deployed we can workaround it in the VDSO by avoiding use of
r30.

Note this only works with GCC, clang does not support -ffixed-rN.

1: https://go-review.googlesource.com/c/go/+/328110

Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.")
Cc: stable@vger.kernel.org # v5.11+
Reported-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Tested-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20210729131244.2595519-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>SMB3: fix readpage for large swap cache</title>
<updated>2021-08-04T10:47:56+00:00</updated>
<author>
<name>Steve French</name>
<email>stfrench@microsoft.com</email>
</author>
<published>2021-07-23T23:35:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=52e9158959d287b68e8fed9fd2f03d6c850263d4'/>
<id>52e9158959d287b68e8fed9fd2f03d6c850263d4</id>
<content type='text'>
commit f2a26a3cff27dfa456fef386fe5df56dcb4b47b6 upstream.

readpage was calculating the offset of the page incorrectly
for the case of large swapcaches.

    loff_t offset = (loff_t)page-&gt;index &lt;&lt; PAGE_SHIFT;

As pointed out by Matthew Wilcox, this needs to use
page_file_offset() to calculate the offset instead.
Pages coming from the swap cache have page-&gt;index set
to their index within the swapcache, not within the backing
file.  For a sufficiently large swapcache, we could have
overlapping values of page-&gt;index within the same backing file.

Suggested by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Cc: &lt;stable@vger.kernel.org&gt; # v5.7+
Reviewed-by: Ronnie Sahlberg &lt;lsahlber@redhat.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&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 f2a26a3cff27dfa456fef386fe5df56dcb4b47b6 upstream.

readpage was calculating the offset of the page incorrectly
for the case of large swapcaches.

    loff_t offset = (loff_t)page-&gt;index &lt;&lt; PAGE_SHIFT;

As pointed out by Matthew Wilcox, this needs to use
page_file_offset() to calculate the offset instead.
Pages coming from the swap cache have page-&gt;index set
to their index within the swapcache, not within the backing
file.  For a sufficiently large swapcache, we could have
overlapping values of page-&gt;index within the same backing file.

Suggested by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Cc: &lt;stable@vger.kernel.org&gt; # v5.7+
Reviewed-by: Ronnie Sahlberg &lt;lsahlber@redhat.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
