9c6f42e925
A possible ABBA lock can happen with RTNL and vlan_rwsem.
For example:
Flow A: Device Flush
__ipoib_ib_dev_flush
down_read(vlan_rwsem) // Lock A
ipoib_flush_ah
flush_workqueue(priv->wq) // Wait for completion
A work on shared WQ (Mcast carrier)
ipoib_mcast_carrier_on_task
while (!rtnl_trylock()) // Wait for lock B
Flow B: Sysfs PKEY delete
ipoib_vlan_delete
lock(RTNL) // Lock B
down_write(vlan_rwsem) // Wait for lock A
This can happen with PKEY creates as well. The solution is to release
the RTNL lock in sysfs functions in case it is not possible to lock
VLAN RW semaphore and reset the SYS call.
Fixes: 69956d83267e ("IB/ipoib: Sync between remove_one to sysfs calls that use rtnl_lock")
Signed-off-by: Shalom Lagziel <shaloml@mellanox.com>
Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
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.