d3c6dd1fb3
During release of the syncpt, we remove it from the list of syncpt and
the tree, but only if it is not already been removed. However, during
signaling, we first remove the syncpt from the list. So, if we
concurrently free and signal the syncpt, the free may decide that it is
not part of the tree and immediately free itself -- meanwhile the
signaler goes on to use the now freed datastructure.
In particular, we get struck by commit 0e2f733addbf ("dma-buf: make
dma_fence structure a bit smaller v2") as the cb_list is immediately
clobbered by the kfree_rcu.
v2: Avoid calling into timeline_fence_release() from under the spinlock
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111381
Fixes: d3862e44daa7 ("dma-buf/sw-sync: Fix locking around sync_timeline lists")
References: 0e2f733addbf ("dma-buf: make dma_fence structure a bit smaller v2")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: <stable@vger.kernel.org> # v4.14+
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190812154247.20508-1-chris@chris-wilson.co.uk
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.