<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/misc, branch v4.19.94</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>altera-stapl: check for a null key before strcasecmp'ing it</title>
<updated>2019-12-13T07:51:56+00:00</updated>
<author>
<name>Colin Ian King</name>
<email>colin.king@canonical.com</email>
</author>
<published>2018-11-24T12:34:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f6ea3c03ec082abfe2b6519e93f10fe9ec37c5a2'/>
<id>f6ea3c03ec082abfe2b6519e93f10fe9ec37c5a2</id>
<content type='text'>
[ Upstream commit 9ccb645683ef46e3c52c12c088a368baa58447d4 ]

Currently the null check on key is occurring after the strcasecmp on
the key, hence there is a potential null pointer dereference on key.
Fix this by checking if key is null first. Also replace the == 0
check on strcasecmp with just the ! operator.

Detected by CoverityScan, CID#1248787 ("Dereference before null check")

Fixes: fa766c9be58b ("[media] Altera FPGA firmware download module")
Signed-off-by: Colin Ian King &lt;colin.king@canonical.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.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 9ccb645683ef46e3c52c12c088a368baa58447d4 ]

Currently the null check on key is occurring after the strcasecmp on
the key, hence there is a potential null pointer dereference on key.
Fix this by checking if key is null first. Also replace the == 0
check on strcasecmp with just the ! operator.

Detected by CoverityScan, CID#1248787 ("Dereference before null check")

Fixes: fa766c9be58b ("[media] Altera FPGA firmware download module")
Signed-off-by: Colin Ian King &lt;colin.king@canonical.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mei: me: add comet point V device id</title>
<updated>2019-12-05T08:21:27+00:00</updated>
<author>
<name>Alexander Usyskin</name>
<email>alexander.usyskin@intel.com</email>
</author>
<published>2019-11-05T15:05:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=728fd8373780ed9ce1a9af9904c13c5578a55c7f'/>
<id>728fd8373780ed9ce1a9af9904c13c5578a55c7f</id>
<content type='text'>
commit 82b29b9f72afdccb40ea5f3c13c6a3cb65a597bc upstream.

Comet Point (Comet Lake) V device id.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Alexander Usyskin &lt;alexander.usyskin@intel.com&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191105150514.14010-2-tomas.winkler@intel.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 82b29b9f72afdccb40ea5f3c13c6a3cb65a597bc upstream.

Comet Point (Comet Lake) V device id.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Alexander Usyskin &lt;alexander.usyskin@intel.com&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191105150514.14010-2-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>mei: bus: prefix device names on bus with the bus name</title>
<updated>2019-12-05T08:21:26+00:00</updated>
<author>
<name>Alexander Usyskin</name>
<email>alexander.usyskin@intel.com</email>
</author>
<published>2019-11-05T15:05:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e99fe2c49fc57fce9f492b7543979b12c746557c'/>
<id>e99fe2c49fc57fce9f492b7543979b12c746557c</id>
<content type='text'>
commit 7a2b9e6ec84588b0be65cc0ae45a65bac431496b upstream.

Add parent device name to the name of devices on bus to avoid
device names collisions for same client UUID available
from different MEI heads. Namely this prevents sysfs collision under
/sys/bus/mei/device/

In the device part leave just UUID other parameters that are
required for device matching are not required here and are
just bloating the name.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Alexander Usyskin &lt;alexander.usyskin@intel.com&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191105150514.14010-1-tomas.winkler@intel.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 7a2b9e6ec84588b0be65cc0ae45a65bac431496b upstream.

Add parent device name to the name of devices on bus to avoid
device names collisions for same client UUID available
from different MEI heads. Namely this prevents sysfs collision under
/sys/bus/mei/device/

In the device part leave just UUID other parameters that are
required for device matching are not required here and are
just bloating the name.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Alexander Usyskin &lt;alexander.usyskin@intel.com&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191105150514.14010-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>misc: mic: fix a DMA pool free failure</title>
<updated>2019-12-01T08:16:22+00:00</updated>
<author>
<name>Wenwen Wang</name>
<email>wang6495@umn.edu</email>
</author>
<published>2018-10-10T23:38:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d11d985d0a8285cc308a61c2464ad68e8e1f4ff8'/>
<id>d11d985d0a8285cc308a61c2464ad68e8e1f4ff8</id>
<content type='text'>
[ Upstream commit 6b995f4eec34745f6cb20d66d5277611f0b3c3fa ]

In _scif_prog_signal(), the boolean variable 'x100' is used to indicate
whether the MIC Coprocessor is X100. If 'x100' is true, the status
descriptor will be used to write the value to the destination. Otherwise, a
DMA pool will be allocated for this purpose. Specifically, if the DMA pool
is allocated successfully, two memory addresses will be returned. One is
for the CPU and the other is for the device to access the DMA pool. The
former is stored to the variable 'status' and the latter is stored to the
variable 'src'. After the allocation, the address in 'src' is saved to
'status-&gt;src_dma_addr', which is actually in the DMA pool, and 'src' is
then modified.

Later on, if an error occurs, the execution flow will transfer to the label
'dma_fail', which will check 'x100' and free up the allocated DMA pool if
'x100' is false. The point here is that 'status-&gt;src_dma_addr' is used for
freeing up the DMA pool. As mentioned before, 'status-&gt;src_dma_addr' is in
the DMA pool. And thus, the device is able to modify this data. This can
potentially cause failures when freeing up the DMA pool because of the
modified device address.

This patch avoids the above issue by using the variable 'src' (with
necessary calculation) to free up the DMA pool.

Signed-off-by: Wenwen Wang &lt;wang6495@umn.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.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 6b995f4eec34745f6cb20d66d5277611f0b3c3fa ]

In _scif_prog_signal(), the boolean variable 'x100' is used to indicate
whether the MIC Coprocessor is X100. If 'x100' is true, the status
descriptor will be used to write the value to the destination. Otherwise, a
DMA pool will be allocated for this purpose. Specifically, if the DMA pool
is allocated successfully, two memory addresses will be returned. One is
for the CPU and the other is for the device to access the DMA pool. The
former is stored to the variable 'status' and the latter is stored to the
variable 'src'. After the allocation, the address in 'src' is saved to
'status-&gt;src_dma_addr', which is actually in the DMA pool, and 'src' is
then modified.

Later on, if an error occurs, the execution flow will transfer to the label
'dma_fail', which will check 'x100' and free up the allocated DMA pool if
'x100' is false. The point here is that 'status-&gt;src_dma_addr' is used for
freeing up the DMA pool. As mentioned before, 'status-&gt;src_dma_addr' is in
the DMA pool. And thus, the device is able to modify this data. This can
potentially cause failures when freeing up the DMA pool because of the
modified device address.

This patch avoids the above issue by using the variable 'src' (with
necessary calculation) to free up the DMA pool.

Signed-off-by: Wenwen Wang &lt;wang6495@umn.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>misc: cxl: Fix possible null pointer dereference</title>
<updated>2019-11-24T07:21:03+00:00</updated>
<author>
<name>zhong jiang</name>
<email>zhongjiang@huawei.com</email>
</author>
<published>2018-10-04T05:02:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5d017065cec9b946e709ec18ae2a59594ee94736'/>
<id>5d017065cec9b946e709ec18ae2a59594ee94736</id>
<content type='text'>
[ Upstream commit 3dac3583bf1a61db6aaf31dfd752c677a4400afd ]

It is not safe to dereference an object before a null test. It is
not needed and just remove them. Ftrace can be used instead.

Signed-off-by: zhong jiang &lt;zhongjiang@huawei.com&gt;
Acked-by: Andrew Donnellan &lt;andrew.donnellan@au1.ibm.com&gt;
Acked-by: Frederic Barrat &lt;fbarrat@linux.ibm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.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 3dac3583bf1a61db6aaf31dfd752c677a4400afd ]

It is not safe to dereference an object before a null test. It is
not needed and just remove them. Ftrace can be used instead.

Signed-off-by: zhong jiang &lt;zhongjiang@huawei.com&gt;
Acked-by: Andrew Donnellan &lt;andrew.donnellan@au1.ibm.com&gt;
Acked-by: Frederic Barrat &lt;fbarrat@linux.ibm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>misc: genwqe: should return proper error value.</title>
<updated>2019-11-20T17:47:31+00:00</updated>
<author>
<name>zhong jiang</name>
<email>zhongjiang@huawei.com</email>
</author>
<published>2018-09-20T02:29:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=728a7552dc498b06c517a11f4053802c2f5a5b7e'/>
<id>728a7552dc498b06c517a11f4053802c2f5a5b7e</id>
<content type='text'>
[ Upstream commit 02241995b004faa7d9ff628e97f24056190853f8 ]

The function should return -EFAULT when copy_from_user fails. Even
though the caller does not distinguish them. but we should keep backward
compatibility.

Signed-off-by: zhong jiang &lt;zhongjiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.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 02241995b004faa7d9ff628e97f24056190853f8 ]

The function should return -EFAULT when copy_from_user fails. Even
though the caller does not distinguish them. but we should keep backward
compatibility.

Signed-off-by: zhong jiang &lt;zhongjiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>misc: kgdbts: Fix restrict error</title>
<updated>2019-11-20T17:47:31+00:00</updated>
<author>
<name>Laura Abbott</name>
<email>labbott@redhat.com</email>
</author>
<published>2018-09-11T17:44:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6707b1ba53be158b5526e53c909d5a1ad61e8d8a'/>
<id>6707b1ba53be158b5526e53c909d5a1ad61e8d8a</id>
<content type='text'>
[ Upstream commit fa0218ef733e6f247a1a3986e3eb12460064ac77 ]

kgdbts current fails when compiled with restrict:

drivers/misc/kgdbts.c: In function ‘configure_kgdbts’:
drivers/misc/kgdbts.c:1070:2: error: ‘strcpy’ source argument is the same as destination [-Werror=restrict]
  strcpy(config, opt);
  ^~~~~~~~~~~~~~~~~~~

As the error says, config is being used in both the source and destination.
Refactor the code to avoid the extra copy and put the parsing closer to
the actual location.

Signed-off-by: Laura Abbott &lt;labbott@redhat.com&gt;
Acked-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.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 fa0218ef733e6f247a1a3986e3eb12460064ac77 ]

kgdbts current fails when compiled with restrict:

drivers/misc/kgdbts.c: In function ‘configure_kgdbts’:
drivers/misc/kgdbts.c:1070:2: error: ‘strcpy’ source argument is the same as destination [-Werror=restrict]
  strcpy(config, opt);
  ^~~~~~~~~~~~~~~~~~~

As the error says, config is being used in both the source and destination.
Refactor the code to avoid the extra copy and put the parsing closer to
the actual location.

Signed-off-by: Laura Abbott &lt;labbott@redhat.com&gt;
Acked-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mei: avoid FW version request on Ibex Peak and earlier</title>
<updated>2019-10-17T20:45:10+00:00</updated>
<author>
<name>Alexander Usyskin</name>
<email>alexander.usyskin@intel.com</email>
</author>
<published>2019-10-04T18:17:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce20fd3e1530b4158008cef147576e1e6ec5175e'/>
<id>ce20fd3e1530b4158008cef147576e1e6ec5175e</id>
<content type='text'>
commit f8204f0ddd62966a0e79c2804963a21e3540dd82 upstream.

The fixed MKHI client on PCH 6 gen platforms
does not support fw version retrieval.
The error is not fatal, but it fills up the kernel logs and
slows down the driver start.
This patch disables requesting FW version on GEN6 and earlier platforms.

Fixes warning:
[   15.964298] mei mei::55213584-9a29-4916-badf-0fb7ed682aeb:01: Could not read FW version
[   15.964301] mei mei::55213584-9a29-4916-badf-0fb7ed682aeb:01: version command failed -5

Cc: &lt;stable@vger.kernel.org&gt; +v4.18
Cc: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Signed-off-by: Alexander Usyskin &lt;alexander.usyskin@intel.com&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191004181722.31374-1-tomas.winkler@intel.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 f8204f0ddd62966a0e79c2804963a21e3540dd82 upstream.

The fixed MKHI client on PCH 6 gen platforms
does not support fw version retrieval.
The error is not fatal, but it fills up the kernel logs and
slows down the driver start.
This patch disables requesting FW version on GEN6 and earlier platforms.

Fixes warning:
[   15.964298] mei mei::55213584-9a29-4916-badf-0fb7ed682aeb:01: Could not read FW version
[   15.964301] mei mei::55213584-9a29-4916-badf-0fb7ed682aeb:01: version command failed -5

Cc: &lt;stable@vger.kernel.org&gt; +v4.18
Cc: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Signed-off-by: Alexander Usyskin &lt;alexander.usyskin@intel.com&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191004181722.31374-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>mei: me: add comet point (lake) LP device ids</title>
<updated>2019-10-17T20:45:09+00:00</updated>
<author>
<name>Tomas Winkler</name>
<email>tomas.winkler@intel.com</email>
</author>
<published>2019-10-01T23:59:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d7e57796b6c0d408bc067db084c66a0085ed49ca'/>
<id>d7e57796b6c0d408bc067db084c66a0085ed49ca</id>
<content type='text'>
commit 4d86dfd38285c83a6df01093b8547f742e3b2470 upstream.

Add Comet Point devices IDs for Comet Lake U platforms.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191001235958.19979-1-tomas.winkler@intel.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 4d86dfd38285c83a6df01093b8547f742e3b2470 upstream.

Add Comet Point devices IDs for Comet Lake U platforms.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Tomas Winkler &lt;tomas.winkler@intel.com&gt;
Link: https://lore.kernel.org/r/20191001235958.19979-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>VMCI: Release resource if the work is already queued</title>
<updated>2019-09-06T08:22:20+00:00</updated>
<author>
<name>Nadav Amit</name>
<email>namit@vmware.com</email>
</author>
<published>2019-08-20T20:26:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4e77b2ea941b3a3d5aea682528f56e94c9b2da4e'/>
<id>4e77b2ea941b3a3d5aea682528f56e94c9b2da4e</id>
<content type='text'>
commit ba03a9bbd17b149c373c0ea44017f35fc2cd0f28 upstream.

Francois reported that VMware balloon gets stuck after a balloon reset,
when the VMCI doorbell is removed. A similar error can occur when the
balloon driver is removed with the following splat:

[ 1088.622000] INFO: task modprobe:3565 blocked for more than 120 seconds.
[ 1088.622035]       Tainted: G        W         5.2.0 #4
[ 1088.622087] "echo 0 &gt; /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1088.622205] modprobe        D    0  3565   1450 0x00000000
[ 1088.622210] Call Trace:
[ 1088.622246]  __schedule+0x2a8/0x690
[ 1088.622248]  schedule+0x2d/0x90
[ 1088.622250]  schedule_timeout+0x1d3/0x2f0
[ 1088.622252]  wait_for_completion+0xba/0x140
[ 1088.622320]  ? wake_up_q+0x80/0x80
[ 1088.622370]  vmci_resource_remove+0xb9/0xc0 [vmw_vmci]
[ 1088.622373]  vmci_doorbell_destroy+0x9e/0xd0 [vmw_vmci]
[ 1088.622379]  vmballoon_vmci_cleanup+0x6e/0xf0 [vmw_balloon]
[ 1088.622381]  vmballoon_exit+0x18/0xcc8 [vmw_balloon]
[ 1088.622394]  __x64_sys_delete_module+0x146/0x280
[ 1088.622408]  do_syscall_64+0x5a/0x130
[ 1088.622410]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1088.622415] RIP: 0033:0x7f54f62791b7
[ 1088.622421] Code: Bad RIP value.
[ 1088.622421] RSP: 002b:00007fff2a949008 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[ 1088.622426] RAX: ffffffffffffffda RBX: 000055dff8b55d00 RCX: 00007f54f62791b7
[ 1088.622426] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055dff8b55d68
[ 1088.622427] RBP: 000055dff8b55d00 R08: 00007fff2a947fb1 R09: 0000000000000000
[ 1088.622427] R10: 00007f54f62f5cc0 R11: 0000000000000206 R12: 000055dff8b55d68
[ 1088.622428] R13: 0000000000000001 R14: 000055dff8b55d68 R15: 00007fff2a94a3f0

The cause for the bug is that when the "delayed" doorbell is invoked, it
takes a reference on the doorbell entry and schedules work that is
supposed to run the appropriate code and drop the doorbell entry
reference. The code ignores the fact that if the work is already queued,
it will not be scheduled to run one more time. As a result one of the
references would not be dropped. When the code waits for the reference
to get to zero, during balloon reset or module removal, it gets stuck.

Fix it. Drop the reference if schedule_work() indicates that the work is
already queued.

Note that this bug got more apparent (or apparent at all) due to
commit ce664331b248 ("vmw_balloon: VMCI_DOORBELL_SET does not check status").

Fixes: 83e2ec765be03 ("VMCI: doorbell implementation.")
Reported-by: Francois Rigault &lt;rigault.francois@gmail.com&gt;
Cc: Jorgen Hansen &lt;jhansen@vmware.com&gt;
Cc: Adit Ranadive &lt;aditr@vmware.com&gt;
Cc: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Cc: Vishnu DASA &lt;vdasa@vmware.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Nadav Amit &lt;namit@vmware.com&gt;
Reviewed-by: Vishnu Dasa &lt;vdasa@vmware.com&gt;
Link: https://lore.kernel.org/r/20190820202638.49003-1-namit@vmware.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit ba03a9bbd17b149c373c0ea44017f35fc2cd0f28 upstream.

Francois reported that VMware balloon gets stuck after a balloon reset,
when the VMCI doorbell is removed. A similar error can occur when the
balloon driver is removed with the following splat:

[ 1088.622000] INFO: task modprobe:3565 blocked for more than 120 seconds.
[ 1088.622035]       Tainted: G        W         5.2.0 #4
[ 1088.622087] "echo 0 &gt; /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1088.622205] modprobe        D    0  3565   1450 0x00000000
[ 1088.622210] Call Trace:
[ 1088.622246]  __schedule+0x2a8/0x690
[ 1088.622248]  schedule+0x2d/0x90
[ 1088.622250]  schedule_timeout+0x1d3/0x2f0
[ 1088.622252]  wait_for_completion+0xba/0x140
[ 1088.622320]  ? wake_up_q+0x80/0x80
[ 1088.622370]  vmci_resource_remove+0xb9/0xc0 [vmw_vmci]
[ 1088.622373]  vmci_doorbell_destroy+0x9e/0xd0 [vmw_vmci]
[ 1088.622379]  vmballoon_vmci_cleanup+0x6e/0xf0 [vmw_balloon]
[ 1088.622381]  vmballoon_exit+0x18/0xcc8 [vmw_balloon]
[ 1088.622394]  __x64_sys_delete_module+0x146/0x280
[ 1088.622408]  do_syscall_64+0x5a/0x130
[ 1088.622410]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1088.622415] RIP: 0033:0x7f54f62791b7
[ 1088.622421] Code: Bad RIP value.
[ 1088.622421] RSP: 002b:00007fff2a949008 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[ 1088.622426] RAX: ffffffffffffffda RBX: 000055dff8b55d00 RCX: 00007f54f62791b7
[ 1088.622426] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055dff8b55d68
[ 1088.622427] RBP: 000055dff8b55d00 R08: 00007fff2a947fb1 R09: 0000000000000000
[ 1088.622427] R10: 00007f54f62f5cc0 R11: 0000000000000206 R12: 000055dff8b55d68
[ 1088.622428] R13: 0000000000000001 R14: 000055dff8b55d68 R15: 00007fff2a94a3f0

The cause for the bug is that when the "delayed" doorbell is invoked, it
takes a reference on the doorbell entry and schedules work that is
supposed to run the appropriate code and drop the doorbell entry
reference. The code ignores the fact that if the work is already queued,
it will not be scheduled to run one more time. As a result one of the
references would not be dropped. When the code waits for the reference
to get to zero, during balloon reset or module removal, it gets stuck.

Fix it. Drop the reference if schedule_work() indicates that the work is
already queued.

Note that this bug got more apparent (or apparent at all) due to
commit ce664331b248 ("vmw_balloon: VMCI_DOORBELL_SET does not check status").

Fixes: 83e2ec765be03 ("VMCI: doorbell implementation.")
Reported-by: Francois Rigault &lt;rigault.francois@gmail.com&gt;
Cc: Jorgen Hansen &lt;jhansen@vmware.com&gt;
Cc: Adit Ranadive &lt;aditr@vmware.com&gt;
Cc: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Cc: Vishnu DASA &lt;vdasa@vmware.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Nadav Amit &lt;namit@vmware.com&gt;
Reviewed-by: Vishnu Dasa &lt;vdasa@vmware.com&gt;
Link: https://lore.kernel.org/r/20190820202638.49003-1-namit@vmware.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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