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Mahesh Bandewar
de77ecd4ef
The primary issue is that mii-inspect phase updates link-state and
expects changes to be committed during the mii-commit phase. After
the inspect phase if it fails to acquire rtnl-mutex, the commit
phase (bond_mii_commit) doesn't get to run. This partially updated
state stays and makes the internal-state inconsistent.
e.g. setup bond0 => slaves: eth1, eth2
eth1 goes DOWN -> UP
mii_monitor()
mii-inspect()
bond_set_slave_link_state(eth1, UP, DontNotify)
rtnl_trylock() <- fails!
Next mii-monitor round
eth1: No change
mii_monitor()
mii-inspect()
eth1->link == current-status (ethtool_ops->get_link)
no-change-detected
End result:
eth1:
Link = BOND_LINK_UP
Speed = 0xfffff [SpeedUnknown]
Duplex = 0xff [DuplexUnknown]
This doesn't always happen but for some unlucky machines in a large set
of machines it creates problems.
The fix for this is to avoid making changes during inspect phase and
postpone them until acquiring the rtnl-mutex / invoking commit phase.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.