<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/infiniband/ulp, branch v5.7</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>IB/ipoib: Fix double free of skb in case of multicast traffic in CM mode</title>
<updated>2020-05-28T00:14:09+00:00</updated>
<author>
<name>Valentine Fatiev</name>
<email>valentinef@mellanox.com</email>
</author>
<published>2020-05-27T13:47:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1acba6a817852d4aa7916d5c4f2c82f702ee9224'/>
<id>1acba6a817852d4aa7916d5c4f2c82f702ee9224</id>
<content type='text'>
When connected mode is set, and we have connected and datagram traffic in
parallel, ipoib might crash with double free of datagram skb.

The current mechanism assumes that the order in the completion queue is
the same as the order of sent packets for all QPs. Order is kept only for
specific QP, in case of mixed UD and CM traffic we have few QPs (one UD and
few CM's) in parallel.

The problem:
----------------------------------------------------------

Transmit queue:
-----------------
UD skb pointer kept in queue itself, CM skb kept in spearate queue and
uses transmit queue as a placeholder to count the number of total
transmitted packets.

0   1   2   3   4  5  6  7  8   9  10  11 12 13 .........127
------------------------------------------------------------
NL ud1 UD2 CM1 ud3 cm2 cm3 ud4 cm4 ud5 NL NL NL ...........
------------------------------------------------------------
    ^                                  ^
   tail                               head

Completion queue (problematic scenario) - the order not the same as in
the transmit queue:

  1  2  3  4  5  6  7  8  9
------------------------------------
 ud1 CM1 UD2 ud3 cm2 cm3 ud4 cm4 ud5
------------------------------------

1. CM1 'wc' processing
   - skb freed in cm separate ring.
   - tx_tail of transmit queue increased although UD2 is not freed.
     Now driver assumes UD2 index is already freed and it could be used for
     new transmitted skb.

0   1   2   3   4  5  6  7  8   9  10  11 12 13 .........127
------------------------------------------------------------
NL NL  UD2 CM1 ud3 cm2 cm3 ud4 cm4 ud5 NL NL NL ...........
------------------------------------------------------------
        ^   ^                       ^
      (Bad)tail                    head
(Bad - Could be used for new SKB)

In this case (due to heavy load) UD2 skb pointer could be replaced by new
transmitted packet UD_NEW, as the driver assumes its free.  At this point
we will have to process two 'wc' with same index but we have only one
pointer to free.

During second attempt to free the same skb we will have NULL pointer
exception.

2. UD2 'wc' processing
   - skb freed according the index we got from 'wc', but it was already
     overwritten by mistake. So actually the skb that was released is the
     skb of the new transmitted packet and not the original one.

3. UD_NEW 'wc' processing
   - attempt to free already freed skb. NUll pointer exception.

The fix:
-----------------------------------------------------------------------

The fix is to stop using the UD ring as a placeholder for CM packets, the
cyclic ring variables tx_head and tx_tail will manage the UD tx_ring, a
new cyclic variables global_tx_head and global_tx_tail are introduced for
managing and counting the overall outstanding sent packets, then the send
queue will be stopped and waken based on these variables only.

Note that no locking is needed since global_tx_head is updated in the xmit
flow and global_tx_tail is updated in the NAPI flow only.  A previous
attempt tried to use one variable to count the outstanding sent packets,
but it did not work since xmit and NAPI flows can run at the same time and
the counter will be updated wrongly. Thus, we use the same simple cyclic
head and tail scheme that we have today for the UD tx_ring.

Fixes: 2c104ea68350 ("IB/ipoib: Get rid of the tx_outstanding variable in all modes")
Link: https://lore.kernel.org/r/20200527134705.480068-1-leon@kernel.org
Signed-off-by: Valentine Fatiev &lt;valentinef@mellanox.com&gt;
Signed-off-by: Alaa Hleihel &lt;alaa@mellanox.com&gt;
Signed-off-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Acked-by: Doug Ledford &lt;dledford@redhat.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When connected mode is set, and we have connected and datagram traffic in
parallel, ipoib might crash with double free of datagram skb.

The current mechanism assumes that the order in the completion queue is
the same as the order of sent packets for all QPs. Order is kept only for
specific QP, in case of mixed UD and CM traffic we have few QPs (one UD and
few CM's) in parallel.

The problem:
----------------------------------------------------------

Transmit queue:
-----------------
UD skb pointer kept in queue itself, CM skb kept in spearate queue and
uses transmit queue as a placeholder to count the number of total
transmitted packets.

0   1   2   3   4  5  6  7  8   9  10  11 12 13 .........127
------------------------------------------------------------
NL ud1 UD2 CM1 ud3 cm2 cm3 ud4 cm4 ud5 NL NL NL ...........
------------------------------------------------------------
    ^                                  ^
   tail                               head

Completion queue (problematic scenario) - the order not the same as in
the transmit queue:

  1  2  3  4  5  6  7  8  9
------------------------------------
 ud1 CM1 UD2 ud3 cm2 cm3 ud4 cm4 ud5
------------------------------------

1. CM1 'wc' processing
   - skb freed in cm separate ring.
   - tx_tail of transmit queue increased although UD2 is not freed.
     Now driver assumes UD2 index is already freed and it could be used for
     new transmitted skb.

0   1   2   3   4  5  6  7  8   9  10  11 12 13 .........127
------------------------------------------------------------
NL NL  UD2 CM1 ud3 cm2 cm3 ud4 cm4 ud5 NL NL NL ...........
------------------------------------------------------------
        ^   ^                       ^
      (Bad)tail                    head
(Bad - Could be used for new SKB)

In this case (due to heavy load) UD2 skb pointer could be replaced by new
transmitted packet UD_NEW, as the driver assumes its free.  At this point
we will have to process two 'wc' with same index but we have only one
pointer to free.

During second attempt to free the same skb we will have NULL pointer
exception.

2. UD2 'wc' processing
   - skb freed according the index we got from 'wc', but it was already
     overwritten by mistake. So actually the skb that was released is the
     skb of the new transmitted packet and not the original one.

3. UD_NEW 'wc' processing
   - attempt to free already freed skb. NUll pointer exception.

The fix:
-----------------------------------------------------------------------

The fix is to stop using the UD ring as a placeholder for CM packets, the
cyclic ring variables tx_head and tx_tail will manage the UD tx_ring, a
new cyclic variables global_tx_head and global_tx_tail are introduced for
managing and counting the overall outstanding sent packets, then the send
queue will be stopped and waken based on these variables only.

Note that no locking is needed since global_tx_head is updated in the xmit
flow and global_tx_tail is updated in the NAPI flow only.  A previous
attempt tried to use one variable to count the outstanding sent packets,
but it did not work since xmit and NAPI flows can run at the same time and
the counter will be updated wrongly. Thus, we use the same simple cyclic
head and tail scheme that we have today for the UD tx_ring.

Fixes: 2c104ea68350 ("IB/ipoib: Get rid of the tx_outstanding variable in all modes")
Link: https://lore.kernel.org/r/20200527134705.480068-1-leon@kernel.org
Signed-off-by: Valentine Fatiev &lt;valentinef@mellanox.com&gt;
Signed-off-by: Alaa Hleihel &lt;alaa@mellanox.com&gt;
Signed-off-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Acked-by: Doug Ledford &lt;dledford@redhat.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma</title>
<updated>2020-04-02T01:18:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-04-02T01:18:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=919dce24701f7b34681a6a1d3ef95c9f6c4fb1cc'/>
<id>919dce24701f7b34681a6a1d3ef95c9f6c4fb1cc</id>
<content type='text'>
Pull rdma updates from Jason Gunthorpe:
 "The majority of the patches are cleanups, refactorings and clarity
  improvements.

  This cycle saw some more activity from Syzkaller, I think we are now
  clean on all but one of those bugs, including the long standing and
  obnoxious rdma_cm locking design defect. Continue to see many drivers
  getting cleanups, with a few new user visible features.

  Summary:

   - Various driver updates for siw, bnxt_re, rxe, efa, mlx5, hfi1

   - Lots of cleanup patches for hns

   - Convert more places to use refcount

   - Aggressively lock the RDMA CM code that syzkaller says isn't
     working

   - Work to clarify ib_cm

   - Use the new ib_device lifecycle model in bnxt_re

   - Fix mlx5's MR cache which seems to be failing more often with the
     new ODP code

   - mlx5 'dynamic uar' and 'tx steering' user interfaces"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (144 commits)
  RDMA/bnxt_re: make bnxt_re_ib_init static
  IB/qib: Delete struct qib_ivdev.qp_rnd
  RDMA/hns: Fix uninitialized variable bug
  RDMA/hns: Modify the mask of QP number for CQE of hip08
  RDMA/hns: Reduce the maximum number of extend SGE per WQE
  RDMA/hns: Reduce PFC frames in congestion scenarios
  RDMA/mlx5: Add support for RDMA TX flow table
  net/mlx5: Add support for RDMA TX steering
  IB/hfi1: Call kobject_put() when kobject_init_and_add() fails
  IB/hfi1: Fix memory leaks in sysfs registration and unregistration
  IB/mlx5: Move to fully dynamic UAR mode once user space supports it
  IB/mlx5: Limit the scope of struct mlx5_bfreg_info to mlx5_ib
  IB/mlx5: Extend QP creation to get uar page index from user space
  IB/mlx5: Extend CQ creation to get uar page index from user space
  IB/mlx5: Expose UAR object and its alloc/destroy commands
  IB/hfi1: Get rid of a warning
  RDMA/hns: Remove redundant judgment of qp_type
  RDMA/hns: Remove redundant assignment of wc-&gt;smac when polling cq
  RDMA/hns: Remove redundant qpc setup operations
  RDMA/hns: Remove meaningless prints
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull rdma updates from Jason Gunthorpe:
 "The majority of the patches are cleanups, refactorings and clarity
  improvements.

  This cycle saw some more activity from Syzkaller, I think we are now
  clean on all but one of those bugs, including the long standing and
  obnoxious rdma_cm locking design defect. Continue to see many drivers
  getting cleanups, with a few new user visible features.

  Summary:

   - Various driver updates for siw, bnxt_re, rxe, efa, mlx5, hfi1

   - Lots of cleanup patches for hns

   - Convert more places to use refcount

   - Aggressively lock the RDMA CM code that syzkaller says isn't
     working

   - Work to clarify ib_cm

   - Use the new ib_device lifecycle model in bnxt_re

   - Fix mlx5's MR cache which seems to be failing more often with the
     new ODP code

   - mlx5 'dynamic uar' and 'tx steering' user interfaces"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (144 commits)
  RDMA/bnxt_re: make bnxt_re_ib_init static
  IB/qib: Delete struct qib_ivdev.qp_rnd
  RDMA/hns: Fix uninitialized variable bug
  RDMA/hns: Modify the mask of QP number for CQE of hip08
  RDMA/hns: Reduce the maximum number of extend SGE per WQE
  RDMA/hns: Reduce PFC frames in congestion scenarios
  RDMA/mlx5: Add support for RDMA TX flow table
  net/mlx5: Add support for RDMA TX steering
  IB/hfi1: Call kobject_put() when kobject_init_and_add() fails
  IB/hfi1: Fix memory leaks in sysfs registration and unregistration
  IB/mlx5: Move to fully dynamic UAR mode once user space supports it
  IB/mlx5: Limit the scope of struct mlx5_bfreg_info to mlx5_ib
  IB/mlx5: Extend QP creation to get uar page index from user space
  IB/mlx5: Extend CQ creation to get uar page index from user space
  IB/mlx5: Expose UAR object and its alloc/destroy commands
  IB/hfi1: Get rid of a warning
  RDMA/hns: Remove redundant judgment of qp_type
  RDMA/hns: Remove redundant assignment of wc-&gt;smac when polling cq
  RDMA/hns: Remove redundant qpc setup operations
  RDMA/hns: Remove meaningless prints
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/hfi1: Get rid of a warning</title>
<updated>2020-03-27T15:51:04+00:00</updated>
<author>
<name>Mauro Carvalho Chehab</name>
<email>mchehab+huawei@kernel.org</email>
</author>
<published>2020-03-17T14:54:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a4da83c215ac4e69ef7ae9ec3ee9ef63a3edafdf'/>
<id>a4da83c215ac4e69ef7ae9ec3ee9ef63a3edafdf</id>
<content type='text'>
The right markup for a variable is @foo, and not @foo[].

Using a wrong markup caused this warning:

	./drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h:243: WARNING: Inline strong start-string without end-string.

Link: https://lore.kernel.org/r/9dce702510505556d75a13d9641e09218a4b4a65.1584456635.git.mchehab+huawei@kernel.org
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The right markup for a variable is @foo, and not @foo[].

Using a wrong markup caused this warning:

	./drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h:243: WARNING: Inline strong start-string without end-string.

Link: https://lore.kernel.org/r/9dce702510505556d75a13d9641e09218a4b4a65.1584456635.git.mchehab+huawei@kernel.org
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/iser: Always check sig MR before putting it to the free pool</title>
<updated>2020-03-26T19:46:54+00:00</updated>
<author>
<name>Sergey Gorenko</name>
<email>sergeygo@mellanox.com</email>
</author>
<published>2020-03-25T15:12:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=26e28deb813eed908cf31a6052870b6493ec0e86'/>
<id>26e28deb813eed908cf31a6052870b6493ec0e86</id>
<content type='text'>
libiscsi calls the check_protection transport handler only if SCSI-Respose
is received. So, the handler is never called if iSCSI task is completed
for some other reason like a timeout or error handling. And this behavior
looks correct. But the iSER does not handle this case properly because it
puts a non-checked signature MR to the free pool. Then the error occurs at
reusing the MR because it is not allowed to invalidate a signature MR
without checking.

This commit adds an extra check to iser_unreg_mem_fastreg(), which is a
part of the task cleanup flow. Now the signature MR is checked there if it
is needed.

Link: https://lore.kernel.org/r/20200325151210.1548-1-sergeygo@mellanox.com
Signed-off-by: Sergey Gorenko &lt;sergeygo@mellanox.com&gt;
Reviewed-by: Max Gurtovoy &lt;maxg@mellanox.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
libiscsi calls the check_protection transport handler only if SCSI-Respose
is received. So, the handler is never called if iSCSI task is completed
for some other reason like a timeout or error handling. And this behavior
looks correct. But the iSER does not handle this case properly because it
puts a non-checked signature MR to the free pool. Then the error occurs at
reusing the MR because it is not allowed to invalidate a signature MR
without checking.

This commit adds an extra check to iser_unreg_mem_fastreg(), which is a
part of the task cleanup flow. Now the signature MR is checked there if it
is needed.

Link: https://lore.kernel.org/r/20200325151210.1548-1-sergeygo@mellanox.com
Signed-off-by: Sergey Gorenko &lt;sergeygo@mellanox.com&gt;
Reviewed-by: Max Gurtovoy &lt;maxg@mellanox.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>RDMA/ipoib: reject unsupported coalescing params</title>
<updated>2020-03-07T06:45:55+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2020-03-06T01:05:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=524250a324da0ec5e942b11a8f8536f3bc4872f5'/>
<id>524250a324da0ec5e942b11a8f8536f3bc4872f5</id>
<content type='text'>
Set ethtool_ops-&gt;supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver did not previously reject unsupported parameters.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Reviewed-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Set ethtool_ops-&gt;supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver did not previously reject unsupported parameters.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Reviewed-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'v5.6-rc4' into rdma.git for-next</title>
<updated>2020-03-04T17:11:06+00:00</updated>
<author>
<name>Jason Gunthorpe</name>
<email>jgg@mellanox.com</email>
</author>
<published>2020-03-04T17:11:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c13cac2a21b44c6d18a2cf5485f26eee0fb686f6'/>
<id>c13cac2a21b44c6d18a2cf5485f26eee0fb686f6</id>
<content type='text'>
Required due to dependencies in following patches.

Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Required due to dependencies in following patches.

Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>RDMA/opa_vnic: Delete driver version</title>
<updated>2020-02-27T20:40:40+00:00</updated>
<author>
<name>Leon Romanovsky</name>
<email>leonro@mellanox.com</email>
</author>
<published>2020-02-20T07:12:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=699d9e7542825464acb4e08212bca1b6d5a82593'/>
<id>699d9e7542825464acb4e08212bca1b6d5a82593</id>
<content type='text'>
The default version provided by "ethtool -i" it the correct way
to identify Driver version. There is no need to overwrite it.

Link: https://lore.kernel.org/r/20200220071239.231800-3-leon@kernel.org
Signed-off-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Reviewed-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The default version provided by "ethtool -i" it the correct way
to identify Driver version. There is no need to overwrite it.

Link: https://lore.kernel.org/r/20200220071239.231800-3-leon@kernel.org
Signed-off-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Reviewed-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>RDMA/ipoib: Don't set constant driver version</title>
<updated>2020-02-27T20:40:40+00:00</updated>
<author>
<name>Leon Romanovsky</name>
<email>leonro@mellanox.com</email>
</author>
<published>2020-02-20T07:12:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=968707207141aba5b32871b300dcc601da3afe5c'/>
<id>968707207141aba5b32871b300dcc601da3afe5c</id>
<content type='text'>
There is no need to set driver version in in-tree kernel code.

Link: https://lore.kernel.org/r/20200220071239.231800-2-leon@kernel.org
Signed-off-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Reviewed-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is no need to set driver version in in-tree kernel code.

Link: https://lore.kernel.org/r/20200220071239.231800-2-leon@kernel.org
Signed-off-by: Leon Romanovsky &lt;leonro@mellanox.com&gt;
Reviewed-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>RDMA: Replace zero-length array with flexible-array member</title>
<updated>2020-02-20T17:33:51+00:00</updated>
<author>
<name>Gustavo A. R. Silva</name>
<email>gustavo@embeddedor.com</email>
</author>
<published>2020-02-13T01:04:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5b361328ca649534d721e4eae20c96ccbe702ce7'/>
<id>5b361328ca649534d721e4eae20c96ccbe702ce7</id>
<content type='text'>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com
Signed-off-by: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt; # added a few more
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com
Signed-off-by: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt; # added a few more
</pre>
</div>
</content>
</entry>
<entry>
<title>scsi: Revert "RDMA/isert: Fix a recently introduced regression related to logout"</title>
<updated>2020-02-14T22:13:53+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bvanassche@acm.org</email>
</author>
<published>2020-02-13T05:08:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=76261ada16dcc3be610396a46d35acc3efbda682'/>
<id>76261ada16dcc3be610396a46d35acc3efbda682</id>
<content type='text'>
Since commit 04060db41178 introduces soft lockups when toggling network
interfaces, revert it.

Link: https://marc.info/?l=target-devel&amp;m=158157054906196
Cc: Rahul Kundu &lt;rahul.kundu@chelsio.com&gt;
Cc: Mike Marciniszyn &lt;mike.marciniszyn@intel.com&gt;
Cc: Sagi Grimberg &lt;sagi@grimberg.me&gt;
Reported-by: Dakshaja Uppalapati &lt;dakshaja@chelsio.com&gt;
Fixes: 04060db41178 ("scsi: RDMA/isert: Fix a recently introduced regression related to logout")
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since commit 04060db41178 introduces soft lockups when toggling network
interfaces, revert it.

Link: https://marc.info/?l=target-devel&amp;m=158157054906196
Cc: Rahul Kundu &lt;rahul.kundu@chelsio.com&gt;
Cc: Mike Marciniszyn &lt;mike.marciniszyn@intel.com&gt;
Cc: Sagi Grimberg &lt;sagi@grimberg.me&gt;
Reported-by: Dakshaja Uppalapati &lt;dakshaja@chelsio.com&gt;
Fixes: 04060db41178 ("scsi: RDMA/isert: Fix a recently introduced regression related to logout")
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
