CVE-2024-57920

In the Linux kernel, the following vulnerability has been resolved:

drm/amdkfd: wq_release signals dma_fence only when available

kfd_process_wq_release() signals eviction fence by
dma_fence_signal() which wanrs if dma_fence
is NULL.

kfd_process->ef is initialized by kfd_process_device_init_vm()
through ioctl. That means the fence is NULL for a new
created kfd_process, and close a kfd_process right
after open it will trigger the warning.

This commit conditionally signals the eviction fence
in kfd_process_wq_release() only when it is available.

[ 503.660882] WARNING: CPU: 0 PID: 9 at drivers/dma-buf/dma-fence.c:467 dma_fence_signal+0x74/0xa0
[ 503.782940] Workqueue: kfd_process_wq kfd_process_wq_release [amdgpu]
[ 503.789640] RIP: 0010:dma_fence_signal+0x74/0xa0
[ 503.877620] Call Trace:
[ 503.880066]
[ 503.882168] ? __warn+0xcd/0x260
[ 503.885407] ? dma_fence_signal+0x74/0xa0
[ 503.889416] ? report_bug+0x288/0x2d0
[ 503.893089] ? handle_bug+0x53/0xa0
[ 503.896587] ? exc_invalid_op+0x14/0x50
[ 503.900424] ? asm_exc_invalid_op+0x16/0x20
[ 503.904616] ? dma_fence_signal+0x74/0xa0
[ 503.908626] kfd_process_wq_release+0x6b/0x370 [amdgpu]
[ 503.914081] process_one_work+0x654/0x10a0
[ 503.918186] worker_thread+0x6c3/0xe70
[ 503.921943] ? srso_alias_return_thunk+0x5/0xfbef5
[ 503.926735] ? srso_alias_return_thunk+0x5/0xfbef5
[ 503.931527] ? __kthread_parkme+0x82/0x140
[ 503.935631] ? __pfx_worker_thread+0x10/0x10
[ 503.939904] kthread+0x2a8/0x380
[ 503.943132] ? __pfx_kthread+0x10/0x10
[ 503.946882] ret_from_fork+0x2d/0x70
[ 503.950458] ? __pfx_kthread+0x10/0x10
[ 503.954210] ret_from_fork_asm+0x1a/0x30
[ 503.958142]
[ 503.960328] —[ end trace 0000000000000000 ]—

(cherry picked from commit 2774ef7625adb5fb9e9265c26a59dca7b8fd171e)