c8a5d5ea3b
This seems to have existed for ever but is now more apparant after
commit 9bff18d13473 ("drm/ttm: use per BO cleanup workers")
My analysis: two threads are running, one in the irq signalling the
fence, in dma_fence_signal_timestamp_locked, it has done the
DMA_FENCE_FLAG_SIGNALLED_BIT setting, but hasn't yet reached the
callbacks.
The second thread in nouveau_cli_work_ready, where it sees the fence is
signalled, so then puts the fence, cleanups the object and frees the
work item, which contains the callback.
Thread one goes again and tries to call the callback and causes the
use-after-free.
Proposed fix: lock the fence signalled check in nouveau_cli_work_ready,
so either the callbacks are done or the memory is freed.
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Fixes: 11e451e74050 ("drm/nouveau: remove fence wait code from deferred client work handler")
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://lore.kernel.org/dri-devel/20230615024008.1600281-1-airlied@gmail.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.