3076b3c38a
[ Upstream commit 2d8527f2f911fab84aec04df4788c0c23af3df48 ]
A race condition exists in ccw_device_set_online() that can cause the
online process to fail, leaving the affected device in an inconsistent
state. As a result, subsequent attempts to set that device online fail
with return code ENODEV.
The problem occurs when a path verification request arrives after
a wait for final device state completed, but before the result state
is evaluated.
Fix this by ensuring that the CCW-device lock is held between
determining final state and checking result state.
Note that since:
commit 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")
path verification requests are much more likely to occur during boot,
resulting in an increased chance of this race condition occurring.
Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.