Re: [PATCH 2/3] drm/msm: Allocate memory for disp snapshot with kvzalloc()

[Abhinav Kumar]

On 10/14/2024 9:36 AM, Douglas Anderson wrote:
> With the "drm/msm: add a display mmu fault handler" series [1] we saw
> issues in the field where memory allocation was failing when
> allocating space for registers in msm_disp_state_dump_regs().
> Specifically we were seeing an order 5 allocation fail. It's not
> surprising that order 5 allocations will sometimes fail after the
> system has been up and running for a while.
>
> There's no need here for contiguous memory. Change the allocation to
> kvzalloc() which should make it much less likely to fail.
>
> [1] https://lore.kernel.org/r/20240628214848.4075651-1-quic_abhinavk@xxxxxxxxxxx/
>
> Fixes: 98659487b845 ("drm/msm: add support to take dpu snapshot")
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
>
>   drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

I had some doubts on how this issue happens considering that the devcore 
should automatically release the memory within 5 sec even if userspace 
had not read this. So there is no leak as such, its just that in a 
heavily loaded system, this can happen.

Fix looks okay to me,

Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>