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6fa75685aa
[ Upstream commit 8036e90f92 ]
Acquiring the rtnl lock while holding usdev_lock could result in a
deadlock.
For example:
usnic_ib_query_port()
| mutex_lock(&us_ibdev->usdev_lock)
| ib_get_eth_speed()
| rtnl_lock()
rtnl_lock()
| usnic_ib_netdevice_event()
| mutex_lock(&us_ibdev->usdev_lock)
This commit moves the usdev_lock acquisition after the rtnl lock has been
released.
This is safe to do because usdev_lock is not protecting anything being
accessed in ib_get_eth_speed(). Hence, the correct order of holding locks
(rtnl -> usdev_lock) is not violated.
Signed-off-by: Parvi Kaustubhi <pkaustub@cisco.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.