On 12/12/2024 12:19 PM, Felix Kuehling wrote: > > On 2024-12-11 22:06, Zhu Lingshan wrote: >> kfd_process_wq_release() signals eviction fence by >> dma_fence_signal() which wanrs if dma_fence >> is NULL. > That's news to me. Looking at the dma_fence_signal implementation on amd-staging-drm-next, it just silently returns -EINVAL if the fence pointer is NULL. I see the same in Linux 6.12.4: https://elixir.bootlin.com/linux/v6.12.4/source/drivers/dma-buf/dma-fence.c#L467 > > Which branch are you on? Linus tree, latest master branch, tag v6.13-rc2 https://github.com/torvalds/linux/blob/master/drivers/dma-buf/dma-fence.c#L467 which is introduced by https://github.com/torvalds/linux/commit/967d226eaae8e40636d257bf8ae55d2c5a912f58 Thanks Lingshan > > Regards, > Felix > >> 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] <TASK> >> [ 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] </TASK> >> [ 503.960328] ---[ end trace 0000000000000000 ]--- >> >> Signed-off-by: Zhu Lingshan <lingshan.zhu@xxxxxxx> >> --- >> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c >> index 87cd52cf4ee9..47d36f43ee8c 100644 >> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c >> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c >> @@ -1159,7 +1159,8 @@ static void kfd_process_wq_release(struct work_struct *work) >> */ >> synchronize_rcu(); >> ef = rcu_access_pointer(p->ef); >> - dma_fence_signal(ef); >> + if (ef) >> + dma_fence_signal(ef); >> >> kfd_process_remove_sysfs(p); >>
