Re: [PATCH v1] drm/shmem-helper: Fix unsetting shmem vaddr while vmap refcount > 0

[Lucas De Marchi]

On Thu, Apr 03, 2025 at 05:26:33PM +0300, Dmitry Osipenko wrote:
> We switched to use refcount_t for vmaps and missed to change the vunmap
> code to properly unset the vmap pointer, which is now cleared while vmap's
> refcount > 0. Clear the cached vmap pointer only when refcounting drops to
> zero to fix the bug.
>
> Fixes: e1fc39a92332 ("drm/shmem-helper: Use refcount_t for vmap_use_count")
> Reported-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> Closes: https://lore.kernel.org/dri-devel/20250403105053.788b0f6e@xxxxxxxxxxxxx/T/#m3dca6d81bedc8d6146a56b82694624fbc6fa4c96
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>


Tested-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>

this fixes it for me when using `qemu ... -device cirrus-vga`

thanks
Lucas De Marchi