s390/cio: fix race condition during online processing
[ Upstream commit 2d8527f2 ] 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 2297791c ("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: 2297791c ("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>
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e43c1245
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