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65b5c326ce
To avoid race condition and avoid UAF cases, implement kref
based queues and protect the below operations using xa lock
a. Getting a queue from xarray
b. Increment/Decrement it's refcount
Every time some one want to access a queue, always get via
amdgpu_userq_get to make sure we have locks in place and get
the object if active.
A userqueue is destroyed on the last refcount is dropped which
typically would be via IOCTL or during fini.
v2: Add the missing drop in one the condition in the signal ioclt [Alex]
v3: remove the queue from the xarray first in the free queue ioctl path
[Christian]
- Pass queue to the amdgpu_userq_put directly.
- make amdgpu_userq_put xa_lock free since we are doing put for each get
only and final put is done via destroy and we remove the queue from xa
with lock.
- use userq_put in fini too so cleanup is done fully.
v4: Use xa_erase directly rather than doing load and erase in free
ioctl. Also remove some of the error logs which could be exploited
by the user to flood the logs [Christian]
Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 4952189b28)
Cc: <stable@vger.kernel.org> # 048c1c4e51: drm/amdgpu/userq: Consolidate wait ioctl exit path
Cc: <stable@vger.kernel.org>