6db541ae27
If a login request fails, the recovery process should be protected
against parallel resets. It is a known issue that freeing and
registering CRQ's in quick succession can result in a failover CRQ from
the VIOS. Processing a failover during login recovery is dangerous for
two reasons:
1. This will result in two parallel initialization processes, this can
cause serious issues during login.
2. It is possible that the failover CRQ is received but never executed.
We get notified of a pending failover through a transport event CRQ.
The reset is not performed until a INIT CRQ request is received.
Previously, if CRQ init fails during login recovery, then the ibmvnic
irq is freed and the login process returned error. If failover_pending
is true (a transport event was received), then the ibmvnic device
would never be able to process the reset since it cannot receive the
CRQ_INIT request due to the irq being freed. This leaved the device
in a inoperable state.
Therefore, the login failure recovery process must be hardened against
these possible issues. Possible failovers (due to quick CRQ free and
init) must be avoided and any issues during re-initialization should be
dealt with instead of being propagated up the stack. This logic is
similar to that of ibmvnic_probe().
Fixes: dff515a3e7 ("ibmvnic: Harden device login requests")
Signed-off-by: Nick Child <nnac123@linux.ibm.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230809221038.51296-5-nnac123@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@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.
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.