On 10/20/2025 11:24 AM, Kim, Jonathan wrote:
>
> [Public]
>
>
> You can see this error message on CTRL-C or gpu reset conditions.
>
> Those don’t seem like application race conditions to me i.e. the app 
> can’t do anything about terminations it can’t see coming.
>
> It appears any bad actor could spam dmesgs with these error messages 
> if they wanted to with the way the driver currently is.
>
If this warning message comes out due to some unexpected things 
happened(like ctrl-c) I think user would not be surprised to see some 
warnings.

Regards

Xiaogang

> Jon
>
> *From:*amd-gfx <amd-gfx-bounces@lists.freedesktop.org> *On Behalf Of 
> *Chen, Xiaogang
> *Sent:* Monday, October 20, 2025 12:00 PM
> *To:* Yang, Philip <Philip.Yang@amd.com>; amd-gfx@lists.freedesktop.org
> *Cc:* Kuehling, Felix <Felix.Kuehling@amd.com>
> *Subject:* Re: [PATCH v3 1/2] drm/amdkfd: Fix false positive queue 
> buffer free warning
>
>
> 	
>
> *Caution:*This message originated from an External Source. Use proper 
> caution when opening attachments, clicking links, or responding.
>
> On 10/20/2025 9:30 AM, Philip Yang wrote:
>
>     Only show warning message if process mm is still alive when queue
>
>     buffer is freed.
>
>     If kfd_lookup_process_by_mm return NULL, means the process is already
>
>     exited and mm is gone, it is fine to free queue buffer.
>
>     Fixes: b049504e211e ("drm/amdkfd: Validate user queue svm memory residency")
>
>     Signed-off-by: Philip Yang<Philip.Yang@amd.com> <mailto:Philip.Yang@amd.com>
>
>     ---
>
>       drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 5 +++--
>
>       1 file changed, 3 insertions(+), 2 deletions(-)
>
>     diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>
>     index 4d4a47313f5b..d1b2f8525f80 100644
>
>     --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>
>     +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>
>     @@ -2487,7 +2487,9 @@ svm_range_unmap_from_cpu(struct mm_struct *mm, struct svm_range *prange,
>
>               bool unmap_parent;
>
>               uint32_t i;
>
>       
>
>     -        if (atomic_read(&prange->queue_refcount)) {
>
>     +        p = kfd_lookup_process_by_mm(mm);
>
> p->mm is null, not p  because driver set p->mm to null. But 
> still prange->queue_refcount is ref of queues from this prange. If app 
> unmap this prange app should have destroyed the queues associated with 
> this prange already. If not, it is not driver issue. I think driver 
> should send this warning anyway to indicate there are queues not 
> destroyed by app before app unmap the prange. It is an app race 
> condition, not driver.
>
> Regards
>
> Xiaogang
>
>     +
>
>     +        if (p && atomic_read(&prange->queue_refcount)) {
>
>                      int r;
>
>       
>
>                      pr_warn("Freeing queue vital buffer 0x%lx, queue evicted\n",
>
>     @@ -2497,7 +2499,6 @@ svm_range_unmap_from_cpu(struct mm_struct *mm, struct svm_range *prange,
>
>                              pr_debug("failed %d to quiesce KFD queues\n", r);
>
>               }
>
>       
>
>     -        p = kfd_lookup_process_by_mm(mm);
>
>               if (!p)
>
>                      return;
>
>               svms = &p->svms;
>