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32685b32d8
[Why]
The issue only occurs during the GPU reset code path.
We first backup the current state prior to commiting 0 streams
internally from DM to DC. This state backup contains valid link
encoder assignments.
DC will clear the link encoder assignments as part of current state
(but not the backup, since it was a copied before the commit) and
free the extra stream reference it held.
DC requires that the link encoder assignments remain cleared/invalid
prior to commiting. Since the backup still has valid assignments we
call the interface post reset to clear them. This routine also
releases the extra reference that the link encoder interface held -
resulting in a double free (and eventually a NULL pointer dereference).
[How]
We'll have to do a full DC commit anyway after GPU reset because
the stream count previously went to 0.
We don't need to retain the assignment that we had backed up, so
just copy off of the now clean current state assignment after the
reset has occcurred with the new link_enc_cfg_copy() interface.
Fixes: 6d63fcc2a3 ("drm/amd/display: Reset link encoder assignments for GPU reset")
Reviewed-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.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.