9d76d46751
When a target swap happens, under certain conditions the node sends a LOGO. The unsolicited ELS logic responds with a reject. The logic may allocate a new node to handle this. Afterward, the new nodes are dropped incorrectly leaving them in a mis-matched state and refcounting causes a use-after-free situation leading to a crash. It is also possible that the unsolicited els handling finds a node which is in an UNUSED state. The handling moves these nodes to NPR state with a refcount of 1. Although the end of the discovery logic assumes a final put will free such a node, there are codes paths which could increment the reference count, thus the node is in NPR state and not released. Eventually this mismatch in state and refcount leads to premature release of the node causing a crash. Fix by always using the discovery engine DEVICE RM event to decrement and release the nodes (rather than explicit code that tried to do it before). This will take care of moving the node to the UNUSED state and then removes the final ref count. If there is a trigger to reuse this node, the transition from the UNUSED state clearly indicates that the initial reference is then incremented and use can continue. Link: https://lore.kernel.org/r/20201115192646.12977-8-james.smart@broadcom.com Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com> Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com> Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.
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.