<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/cdrom/gdrom.c, branch linux-5.7.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>scsi: compat_ioctl: cdrom: Replace .ioctl with .compat_ioctl in four appropriate places</title>
<updated>2020-02-24T20:06:07+00:00</updated>
<author>
<name>Adam Williamson</name>
<email>awilliam@redhat.com</email>
</author>
<published>2020-02-19T16:50:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=03264ddde2453f6877a7d637d84068079632a3c5'/>
<id>03264ddde2453f6877a7d637d84068079632a3c5</id>
<content type='text'>
Arnd Bergmann inadvertently typoed these in d320a9551e394 and 64cbfa96551a;
they seem to be the cause of
https://bugzilla.redhat.com/show_bug.cgi?id=1801353 , invalid SCSI commands
when udev tries to query a DVD drive.

[arnd] Found another instance of the same bug, also introduced in my
compat_ioctl series.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1801353
Link: https://lore.kernel.org/r/20200219165139.3467320-1-arnd@arndb.de
Fixes: c103d6ee69f9 ("compat_ioctl: ide: floppy: add handler")
Fixes: 64cbfa96551a ("compat_ioctl: move cdrom commands into cdrom.c")
Fixes: d320a9551e39 ("compat_ioctl: scsi: move ioctl handling into drivers")
Bisected-by: Chris Murphy &lt;bugzilla@colorremedies.com&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Adam Williamson &lt;awilliam@redhat.com&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>
Arnd Bergmann inadvertently typoed these in d320a9551e394 and 64cbfa96551a;
they seem to be the cause of
https://bugzilla.redhat.com/show_bug.cgi?id=1801353 , invalid SCSI commands
when udev tries to query a DVD drive.

[arnd] Found another instance of the same bug, also introduced in my
compat_ioctl series.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1801353
Link: https://lore.kernel.org/r/20200219165139.3467320-1-arnd@arndb.de
Fixes: c103d6ee69f9 ("compat_ioctl: ide: floppy: add handler")
Fixes: 64cbfa96551a ("compat_ioctl: move cdrom commands into cdrom.c")
Fixes: d320a9551e39 ("compat_ioctl: scsi: move ioctl handling into drivers")
Bisected-by: Chris Murphy &lt;bugzilla@colorremedies.com&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Adam Williamson &lt;awilliam@redhat.com&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>compat_ioctl: move cdrom commands into cdrom.c</title>
<updated>2020-01-03T08:42:52+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2019-11-28T14:55:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=64cbfa96551a1511b9babef06afa06a1c6c4e8f5'/>
<id>64cbfa96551a1511b9babef06afa06a1c6c4e8f5</id>
<content type='text'>
There is no need for the special cases for the cdrom ioctls any more now,
so make sure that each cdrom driver has a .compat_ioctl() callback and
calls cdrom_compat_ioctl() directly there.

Reviewed-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is no need for the special cases for the cdrom ioctls any more now,
so make sure that each cdrom driver has a .compat_ioctl() callback and
calls cdrom_compat_ioctl() directly there.

Reviewed-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>gdrom: Use pr_warn instead of pr_warning</title>
<updated>2019-10-18T13:00:19+00:00</updated>
<author>
<name>Kefeng Wang</name>
<email>wangkefeng.wang@huawei.com</email>
</author>
<published>2019-10-18T03:18:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f8b489980d9427244555dadd9186a76944c1b7d6'/>
<id>f8b489980d9427244555dadd9186a76944c1b7d6</id>
<content type='text'>
As said in commit f2c2cbcc35d4 ("powerpc: Use pr_warn instead of
pr_warning"), removing pr_warning so all logging messages use a
consistent &lt;prefix&gt;_warn style. Let's do it.

Link: http://lkml.kernel.org/r/20191018031850.48498-10-wangkefeng.wang@huawei.com
To: linux-kernel@vger.kernel.org
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Signed-off-by: Petr Mladek &lt;pmladek@suse.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As said in commit f2c2cbcc35d4 ("powerpc: Use pr_warn instead of
pr_warning"), removing pr_warning so all logging messages use a
consistent &lt;prefix&gt;_warn style. Let's do it.

Link: http://lkml.kernel.org/r/20191018031850.48498-10-wangkefeng.wang@huawei.com
To: linux-kernel@vger.kernel.org
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Signed-off-by: Petr Mladek &lt;pmladek@suse.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1</title>
<updated>2019-05-21T09:28:39+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-05-19T13:51:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=16216333235adf51093d0330a934a7e4a03134fe'/>
<id>16216333235adf51093d0330a934a7e4a03134fe</id>
<content type='text'>
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  51 franklin street fifth floor boston ma 02110 1301 usa

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option [no]_[pad]_[ctrl] any later version this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin street fifth floor boston ma
  02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 176 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Jilayne Lovejoy &lt;opensource@jilayne.com&gt;
Reviewed-by: Steve Winslow &lt;swinslow@gmail.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154040.652910950@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  51 franklin street fifth floor boston ma 02110 1301 usa

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option [no]_[pad]_[ctrl] any later version this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin street fifth floor boston ma
  02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 176 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Jilayne Lovejoy &lt;opensource@jilayne.com&gt;
Reviewed-by: Steve Winslow &lt;swinslow@gmail.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154040.652910950@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers"</title>
<updated>2019-04-12T19:35:27+00:00</updated>
<author>
<name>Martin Wilck</name>
<email>mwilck@suse.com</email>
</author>
<published>2019-03-27T13:51:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=773008f6fe0544aa28140ced0504cefba17381aa'/>
<id>773008f6fe0544aa28140ced0504cefba17381aa</id>
<content type='text'>
This reverts commit 9fd097b14918875bd6f125ed699d7bbbba5893ee.

Instead of leaving disk-&gt;events completely empty, we now export the
supported events again, and tell the block layer not to forward events to
user space by not setting DISK_EVENT_FLAG_UEVENT. This allows the block
layer to distinguish between devices that for which events should be
handled in kernel only, and devices which don't support any meda change
events at all.

Cc: Jiri Kosina &lt;jikos@kernel.org&gt;
Cc: Tim Waugh &lt;tim@cyberelk.net&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Martin Wilck &lt;mwilck@suse.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 9fd097b14918875bd6f125ed699d7bbbba5893ee.

Instead of leaving disk-&gt;events completely empty, we now export the
supported events again, and tell the block layer not to forward events to
user space by not setting DISK_EVENT_FLAG_UEVENT. This allows the block
layer to distinguish between devices that for which events should be
handled in kernel only, and devices which don't support any meda change
events at all.

Cc: Jiri Kosina &lt;jikos@kernel.org&gt;
Cc: Tim Waugh &lt;tim@cyberelk.net&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Martin Wilck &lt;mwilck@suse.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>gdrom: fix a memory leak bug</title>
<updated>2018-12-29T15:20:44+00:00</updated>
<author>
<name>Wenwen Wang</name>
<email>wang6495@umn.edu</email>
</author>
<published>2018-12-27T02:15:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=093c48213ee37c3c3ff1cf5ac1aa2a9d8bc66017'/>
<id>093c48213ee37c3c3ff1cf5ac1aa2a9d8bc66017</id>
<content type='text'>
In probe_gdrom(), the buffer pointed by 'gd.cd_info' is allocated through
kzalloc() and is used to hold the information of the gdrom device. To
register and unregister the device, the pointer 'gd.cd_info' is passed to
the functions register_cdrom() and unregister_cdrom(), respectively.
However, this buffer is not freed after it is used, which can cause a
memory leak bug.

This patch simply frees the buffer 'gd.cd_info' in exit_gdrom() to fix the
above issue.

Signed-off-by: Wenwen Wang &lt;wang6495@umn.edu&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In probe_gdrom(), the buffer pointed by 'gd.cd_info' is allocated through
kzalloc() and is used to hold the information of the gdrom device. To
register and unregister the device, the pointer 'gd.cd_info' is passed to
the functions register_cdrom() and unregister_cdrom(), respectively.
However, this buffer is not freed after it is used, which can cause a
memory leak bug.

This patch simply frees the buffer 'gd.cd_info' in exit_gdrom() to fix the
above issue.

Signed-off-by: Wenwen Wang &lt;wang6495@umn.edu&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>gdrom: fix mistake in assignment of error</title>
<updated>2018-10-25T17:17:40+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2018-10-25T14:15:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0a40a93524736c2ce01d82effe2f2bc34d5cf159'/>
<id>0a40a93524736c2ce01d82effe2f2bc34d5cf159</id>
<content type='text'>
Apparently the kbuild bots missed this one originally, but at least
it caught it now. Fix compilation error:

All errors (new ones prefixed by &gt;&gt;):

   drivers/cdrom/gdrom.c: In function 'probe_gdrom':
&gt;&gt; drivers/cdrom/gdrom.c:797:3: error: 'rc' undeclared (first use in this function)
      rc = PTR_ERR(gd.gdrom_rq);
      ^~
   drivers/cdrom/gdrom.c:797:3: note: each undeclared identifier is reported only once for each function it appears in

Fixes: ad5fc6bb7221 ("gdrom: convert to blk-mq")
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Apparently the kbuild bots missed this one originally, but at least
it caught it now. Fix compilation error:

All errors (new ones prefixed by &gt;&gt;):

   drivers/cdrom/gdrom.c: In function 'probe_gdrom':
&gt;&gt; drivers/cdrom/gdrom.c:797:3: error: 'rc' undeclared (first use in this function)
      rc = PTR_ERR(gd.gdrom_rq);
      ^~
   drivers/cdrom/gdrom.c:797:3: note: each undeclared identifier is reported only once for each function it appears in

Fixes: ad5fc6bb7221 ("gdrom: convert to blk-mq")
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cdrom: remove set but not used variable 'tocuse'</title>
<updated>2018-10-25T17:17:39+00:00</updated>
<author>
<name>zhong jiang</name>
<email>zhongjiang@huawei.com</email>
</author>
<published>2018-10-23T12:06:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cdffab7a86b05b207907c391c093023daed5d4a4'/>
<id>cdffab7a86b05b207907c391c093023daed5d4a4</id>
<content type='text'>
tocuse is not used after setting its value. It is safe to remove
the unused variable.

Signed-off-by: zhong jiang &lt;zhongjiang@huawei.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
tocuse is not used after setting its value. It is safe to remove
the unused variable.

Signed-off-by: zhong jiang &lt;zhongjiang@huawei.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>gdrom: convert to blk-mq</title>
<updated>2018-10-16T15:50:39+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2018-10-15T15:01:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ad5fc6bb72214615f300af1f4ed57f71bc3be510'/>
<id>ad5fc6bb72214615f300af1f4ed57f71bc3be510</id>
<content type='text'>
Ditch the deffered list, lock, and workqueue handling. Just mark the
set as being blocking, so we are invoked from a workqueue already.

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Ditch the deffered list, lock, and workqueue handling. Just mark the
set as being blocking, so we are invoked from a workqueue already.

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cdrom: do not call check_disk_change() inside cdrom_open()</title>
<updated>2018-03-09T15:06:35+00:00</updated>
<author>
<name>Maurizio Lombardi</name>
<email>mlombard@redhat.com</email>
</author>
<published>2018-03-09T12:59:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2bbea6e117357d17842114c65e9a9cf2d13ae8a3'/>
<id>2bbea6e117357d17842114c65e9a9cf2d13ae8a3</id>
<content type='text'>
when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block-&gt;s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block-&gt;s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi &lt;mlombard@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block-&gt;s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block-&gt;s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi &lt;mlombard@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
</feed>
