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IB/usnic: Fix potential deadlock
[ 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>
This commit is contained in:
parent
a13daf038b
commit
6fa75685aa
1 changed files with 7 additions and 4 deletions
|
@ -334,13 +334,16 @@ int usnic_ib_query_port(struct ib_device *ibdev, u8 port,
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usnic_dbg("\n");
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mutex_lock(&us_ibdev->usdev_lock);
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if (ib_get_eth_speed(ibdev, port, &props->active_speed,
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&props->active_width)) {
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mutex_unlock(&us_ibdev->usdev_lock);
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&props->active_width))
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return -EINVAL;
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}
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/*
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* usdev_lock is acquired after (and not before) ib_get_eth_speed call
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* because acquiring rtnl_lock in ib_get_eth_speed, while holding
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* usdev_lock could lead to a deadlock.
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*/
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mutex_lock(&us_ibdev->usdev_lock);
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/* props being zeroed by the caller, avoid zeroing it here */
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props->lid = 0;
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