<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/block, branch v4.4.126</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>blk-throttle: make sure expire time isn't too big</title>
<updated>2018-03-22T08:23:22+00:00</updated>
<author>
<name>Shaohua Li</name>
<email>shli@fb.com</email>
</author>
<published>2017-03-27T17:51:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fc23c57dbf90e2c9d5e1e394def93b4d2f190dbd'/>
<id>fc23c57dbf90e2c9d5e1e394def93b4d2f190dbd</id>
<content type='text'>
[ Upstream commit 06cceedcca67a93ac7f7aa93bbd9980c7496d14e ]

cgroup could be throttled to a limit but when all cgroups cross high
limit, queue enters a higher state and so the group should be throttled
to a higher limit. It's possible the cgroup is sleeping because of
throttle and other cgroups don't dispatch IO any more. In this case,
nobody can trigger current downgrade/upgrade logic. To fix this issue,
we could either set up a timer to wakeup the cgroup if other cgroups are
idle or make sure this cgroup doesn't sleep too long. Setting up a timer
means we must change the timer very frequently. This patch chooses the
latter. Making cgroup sleep time not too big wouldn't change cgroup
bps/iops, but could make it wakeup more frequently, which isn't a big
issue because throtl_slice * 8 is already quite big.

Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@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>
[ Upstream commit 06cceedcca67a93ac7f7aa93bbd9980c7496d14e ]

cgroup could be throttled to a limit but when all cgroups cross high
limit, queue enters a higher state and so the group should be throttled
to a higher limit. It's possible the cgroup is sleeping because of
throttle and other cgroups don't dispatch IO any more. In this case,
nobody can trigger current downgrade/upgrade logic. To fix this issue,
we could either set up a timer to wakeup the cgroup if other cgroups are
idle or make sure this cgroup doesn't sleep too long. Setting up a timer
means we must change the timer very frequently. This patch chooses the
latter. Making cgroup sleep time not too big wouldn't change cgroup
bps/iops, but could make it wakeup more frequently, which isn't a big
issue because throtl_slice * 8 is already quite big.

Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>blkcg: fix double free of new_blkg in blkcg_init_queue</title>
<updated>2018-03-22T08:23:19+00:00</updated>
<author>
<name>Hou Tao</name>
<email>houtao1@huawei.com</email>
</author>
<published>2017-02-03T09:19:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=633a5a5235d697b145171ca1e702d3a4f6778131'/>
<id>633a5a5235d697b145171ca1e702d3a4f6778131</id>
<content type='text'>
commit 9b54d816e00425c3a517514e0d677bb3cec49258 upstream.

If blkg_create fails, new_blkg passed as an argument will
be freed by blkg_create, so there is no need to free it again.

Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Cc: Guenter Roeck &lt;linux@roeck-us.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 9b54d816e00425c3a517514e0d677bb3cec49258 upstream.

If blkg_create fails, new_blkg passed as an argument will
be freed by blkg_create, so there is no need to free it again.

Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Cc: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>more bio_map_user_iov() leak fixes</title>
<updated>2017-12-16T09:33:56+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2017-09-23T19:51:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=047a7bb12d63c41569ce9c9e88f5b231fd1f6cf5'/>
<id>047a7bb12d63c41569ce9c9e88f5b231fd1f6cf5</id>
<content type='text'>
commit 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 upstream.

we need to take care of failure exit as well - pages already
in bio should be dropped by analogue of bio_unmap_pages(),
since their refcounts had been bumped only once per reference
in bio.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Guenter Roeck &lt;linux@roeck-us.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 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 upstream.

we need to take care of failure exit as well - pages already
in bio should be dropped by analogue of bio_unmap_pages(),
since their refcounts had been bumped only once per reference
in bio.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: wake up all tasks blocked in get_request()</title>
<updated>2017-12-16T09:33:55+00:00</updated>
<author>
<name>Ming Lei</name>
<email>ming.lei@redhat.com</email>
</author>
<published>2017-11-16T00:08:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7b99b00cf3f07c26ca862ca7defbe370a1b2575b'/>
<id>7b99b00cf3f07c26ca862ca7defbe370a1b2575b</id>
<content type='text'>
[ Upstream commit 34d9715ac1edd50285168dd8d80c972739a4f6a4 ]

Once blk_set_queue_dying() is done in blk_cleanup_queue(), we call
blk_freeze_queue() and wait for q-&gt;q_usage_counter becoming zero. But
if there are tasks blocked in get_request(), q-&gt;q_usage_counter can
never become zero. So we have to wake up all these tasks in
blk_set_queue_dying() first.

Fixes: 3ef28e83ab157997 ("block: generic request_queue reference counting")
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.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>
[ Upstream commit 34d9715ac1edd50285168dd8d80c972739a4f6a4 ]

Once blk_set_queue_dying() is done in blk_cleanup_queue(), we call
blk_freeze_queue() and wait for q-&gt;q_usage_counter becoming zero. But
if there are tasks blocked in get_request(), q-&gt;q_usage_counter can
never become zero. So we have to wake up all these tasks in
blk_set_queue_dying() first.

Fixes: 3ef28e83ab157997 ("block: generic request_queue reference counting")
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "bsg-lib: don't free job in bsg_prepare_job"</title>
<updated>2017-10-21T15:09:03+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-10-19T12:55:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d44e463c9460003f9606cc8ddbee76e49cd46783'/>
<id>d44e463c9460003f9606cc8ddbee76e49cd46783</id>
<content type='text'>
This reverts commit 668cee82cd28d2c38a99f7cbddf3b3fd58f257b9 which was
commit f507b54dccfd8000c517d740bc45f20c74532d18 upstream.

Ben reports:
	That function doesn't exist here (it was introduced in 4.13).
	Instead, this backport has modified bsg_create_job(), creating a
	leak.  Please revert this on the 3.18, 4.4 and 4.9 stable
	branches.

So I'm dropping it from here.

Reported-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Ming Lei &lt;ming.lei@redhat.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 668cee82cd28d2c38a99f7cbddf3b3fd58f257b9 which was
commit f507b54dccfd8000c517d740bc45f20c74532d18 upstream.

Ben reports:
	That function doesn't exist here (it was introduced in 4.13).
	Instead, this backport has modified bsg_create_job(), creating a
	leak.  Please revert this on the 3.18, 4.4 and 4.9 stable
	branches.

So I'm dropping it from here.

Reported-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Ming Lei &lt;ming.lei@redhat.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
</pre>
</div>
</content>
</entry>
<entry>
<title>fix unbalanced page refcounting in bio_map_user_iov</title>
<updated>2017-10-18T07:20:42+00:00</updated>
<author>
<name>Vitaly Mayatskikh</name>
<email>v.mayatskih@gmail.com</email>
</author>
<published>2017-09-22T05:18:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=399c46095eb5d41934c8a99732028a9f1cf0ac50'/>
<id>399c46095eb5d41934c8a99732028a9f1cf0ac50</id>
<content type='text'>
commit 95d78c28b5a85bacbc29b8dba7c04babb9b0d467 upstream.

bio_map_user_iov and bio_unmap_user do unbalanced pages refcounting if
IO vector has small consecutive buffers belonging to the same page.
bio_add_pc_page merges them into one, but the page reference is never
dropped.

Signed-off-by: Vitaly Mayatskikh &lt;v.mayatskih@gmail.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&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 95d78c28b5a85bacbc29b8dba7c04babb9b0d467 upstream.

bio_map_user_iov and bio_unmap_user do unbalanced pages refcounting if
IO vector has small consecutive buffers belonging to the same page.
bio_add_pc_page merges them into one, but the page reference is never
dropped.

Signed-off-by: Vitaly Mayatskikh &lt;v.mayatskih@gmail.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>partitions/efi: Fix integer overflow in GPT size calculation</title>
<updated>2017-10-08T08:14:18+00:00</updated>
<author>
<name>Alden Tondettar</name>
<email>alden.tondettar@gmail.com</email>
</author>
<published>2017-01-15T22:31:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8e8c3d4bb62950c37f086be7d3d775b4879c30df'/>
<id>8e8c3d4bb62950c37f086be7d3d775b4879c30df</id>
<content type='text'>
[ Upstream commit c5082b70adfe8e1ea1cf4a8eff92c9f260e364d2 ]

If a GUID Partition Table claims to have more than 2**25 entries, the
calculation of the partition table size in alloc_read_gpt_entries() will
overflow a 32-bit integer and not enough space will be allocated for the
table.

Nothing seems to get written out of bounds, but later efi_partition() will
read up to 32768 bytes from a 128 byte buffer, possibly OOPSing or exposing
information to /proc/partitions and uevents.

The problem exists on both 64-bit and 32-bit platforms.

Fix the overflow and also print a meaningful debug message if the table
size is too large.

Signed-off-by: Alden Tondettar &lt;alden.tondettar@gmail.com&gt;
Acked-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.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>
[ Upstream commit c5082b70adfe8e1ea1cf4a8eff92c9f260e364d2 ]

If a GUID Partition Table claims to have more than 2**25 entries, the
calculation of the partition table size in alloc_read_gpt_entries() will
overflow a 32-bit integer and not enough space will be allocated for the
table.

Nothing seems to get written out of bounds, but later efi_partition() will
read up to 32768 bytes from a 128 byte buffer, possibly OOPSing or exposing
information to /proc/partitions and uevents.

The problem exists on both 64-bit and 32-bit platforms.

Fix the overflow and also print a meaningful debug message if the table
size is too large.

Signed-off-by: Alden Tondettar &lt;alden.tondettar@gmail.com&gt;
Acked-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bsg-lib: don't free job in bsg_prepare_job</title>
<updated>2017-10-05T07:41:46+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2017-09-07T11:54:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=668cee82cd28d2c38a99f7cbddf3b3fd58f257b9'/>
<id>668cee82cd28d2c38a99f7cbddf3b3fd58f257b9</id>
<content type='text'>
commit f507b54dccfd8000c517d740bc45f20c74532d18 upstream.

The job structure is allocated as part of the request, so we should not
free it in the error path of bsg_prepare_job.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&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 f507b54dccfd8000c517d740bc45f20c74532d18 upstream.

The job structure is allocated as part of the request, so we should not
free it in the error path of bsg_prepare_job.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&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>block: Relax a check in blk_start_queue()</title>
<updated>2017-09-27T09:00:14+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bart.vanassche@wdc.com</email>
</author>
<published>2017-08-17T20:12:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=30e81e7fe197dd14d5b7653c75140ea75fe5c3d4'/>
<id>30e81e7fe197dd14d5b7653c75140ea75fe5c3d4</id>
<content type='text'>
commit 4ddd56b003f251091a67c15ae3fe4a5c5c5e390a upstream.

Calling blk_start_queue() from interrupt context with the queue
lock held and without disabling IRQs, as the skd driver does, is
safe. This patch avoids that loading the skd driver triggers the
following warning:

WARNING: CPU: 11 PID: 1348 at block/blk-core.c:283 blk_start_queue+0x84/0xa0
RIP: 0010:blk_start_queue+0x84/0xa0
Call Trace:
 skd_unquiesce_dev+0x12a/0x1d0 [skd]
 skd_complete_internal+0x1e7/0x5a0 [skd]
 skd_complete_other+0xc2/0xd0 [skd]
 skd_isr_completion_posted.isra.30+0x2a5/0x470 [skd]
 skd_isr+0x14f/0x180 [skd]
 irq_forced_thread_fn+0x2a/0x70
 irq_thread+0x144/0x1a0
 kthread+0x125/0x140
 ret_from_fork+0x2a/0x40

Fixes: commit a038e2536472 ("[PATCH] blk_start_queue() must be called with irq disabled - add warning")
Signed-off-by: Bart Van Assche &lt;bart.vanassche@wdc.com&gt;
Cc: Paolo 'Blaisorblade' Giarrusso &lt;blaisorblade@yahoo.it&gt;
Cc: Andrew Morton &lt;akpm@osdl.org&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Johannes Thumshirn &lt;jthumshirn@suse.de&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 4ddd56b003f251091a67c15ae3fe4a5c5c5e390a upstream.

Calling blk_start_queue() from interrupt context with the queue
lock held and without disabling IRQs, as the skd driver does, is
safe. This patch avoids that loading the skd driver triggers the
following warning:

WARNING: CPU: 11 PID: 1348 at block/blk-core.c:283 blk_start_queue+0x84/0xa0
RIP: 0010:blk_start_queue+0x84/0xa0
Call Trace:
 skd_unquiesce_dev+0x12a/0x1d0 [skd]
 skd_complete_internal+0x1e7/0x5a0 [skd]
 skd_complete_other+0xc2/0xd0 [skd]
 skd_isr_completion_posted.isra.30+0x2a5/0x470 [skd]
 skd_isr+0x14f/0x180 [skd]
 irq_forced_thread_fn+0x2a/0x70
 irq_thread+0x144/0x1a0
 kthread+0x125/0x140
 ret_from_fork+0x2a/0x40

Fixes: commit a038e2536472 ("[PATCH] blk_start_queue() must be called with irq disabled - add warning")
Signed-off-by: Bart Van Assche &lt;bart.vanassche@wdc.com&gt;
Cc: Paolo 'Blaisorblade' Giarrusso &lt;blaisorblade@yahoo.it&gt;
Cc: Andrew Morton &lt;akpm@osdl.org&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Johannes Thumshirn &lt;jthumshirn@suse.de&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>block: fix module reference leak on put_disk() call for cgroups throttle</title>
<updated>2017-07-05T12:37:16+00:00</updated>
<author>
<name>Roman Pen</name>
<email>roman.penyaev@profitbricks.com</email>
</author>
<published>2016-02-09T19:33:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=21d7c733251a5afd87374d3928738026c93e6261'/>
<id>21d7c733251a5afd87374d3928738026c93e6261</id>
<content type='text'>
commit 39a169b62b415390398291080dafe63aec751e0a upstream.

get_disk(),get_gendisk() calls have non explicit side effect: they
increase the reference on the disk owner module.

The following is the correct sequence how to get a disk reference and
to put it:

    disk = get_gendisk(...);

    /* use disk */

    owner = disk-&gt;fops-&gt;owner;
    put_disk(disk);
    module_put(owner);

fs/block_dev.c is aware of this required module_put() call, but f.e.
blkg_conf_finish(), which is located in block/blk-cgroup.c, does not put
a module reference.  To see a leakage in action cgroups throttle config
can be used.  In the following script I'm removing throttle for /dev/ram0
(actually this is NOP, because throttle was never set for this device):

    # lsmod | grep brd
    brd                     5175  0
    # i=100; while [ $i -gt 0 ]; do echo "1:0 0" &gt; \
        /sys/fs/cgroup/blkio/blkio.throttle.read_bps_device; i=$(($i - 1)); \
    done
    # lsmod | grep brd
    brd                     5175  100

Now brd module has 100 references.

The issue is fixed by calling module_put() just right away put_disk().

Signed-off-by: Roman Pen &lt;roman.penyaev@profitbricks.com&gt;
Cc: Gi-Oh Kim &lt;gi-oh.kim@profitbricks.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Cc: Sumit Semwal &lt;sumit.semwal@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit 39a169b62b415390398291080dafe63aec751e0a upstream.

get_disk(),get_gendisk() calls have non explicit side effect: they
increase the reference on the disk owner module.

The following is the correct sequence how to get a disk reference and
to put it:

    disk = get_gendisk(...);

    /* use disk */

    owner = disk-&gt;fops-&gt;owner;
    put_disk(disk);
    module_put(owner);

fs/block_dev.c is aware of this required module_put() call, but f.e.
blkg_conf_finish(), which is located in block/blk-cgroup.c, does not put
a module reference.  To see a leakage in action cgroups throttle config
can be used.  In the following script I'm removing throttle for /dev/ram0
(actually this is NOP, because throttle was never set for this device):

    # lsmod | grep brd
    brd                     5175  0
    # i=100; while [ $i -gt 0 ]; do echo "1:0 0" &gt; \
        /sys/fs/cgroup/blkio/blkio.throttle.read_bps_device; i=$(($i - 1)); \
    done
    # lsmod | grep brd
    brd                     5175  100

Now brd module has 100 references.

The issue is fixed by calling module_put() just right away put_disk().

Signed-off-by: Roman Pen &lt;roman.penyaev@profitbricks.com&gt;
Cc: Gi-Oh Kim &lt;gi-oh.kim@profitbricks.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Cc: Sumit Semwal &lt;sumit.semwal@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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