From: Zack Rusin zackr@vmware.com
[ Upstream commit c451af78f301ff5156998d571c37cab329c10051 ]
Some of our hosts have a bug where rescaning a pci bus results in stale fifo memory being mapped on the host. This makes any fifo communication impossible resulting in various kernel crashes.
Instead of unexpectedly crashing, predictably fail to load the driver which will preserve the system.
Fixes: fb1d9738ca05 ("drm/vmwgfx: Add DRM driver for VMware Virtual GPU") Signed-off-by: Zack Rusin zackr@vmware.com Reviewed-by: Martin Krastev krastevm@vmware.com Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-4-zackr@... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c index 67db472d3493c..a3bfbb6c3e14a 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c @@ -145,6 +145,13 @@ struct vmw_fifo_state *vmw_fifo_create(struct vmw_private *dev_priv) (unsigned int) max, (unsigned int) min, (unsigned int) fifo->capabilities); + + if (unlikely(min >= max)) { + drm_warn(&dev_priv->drm, + "FIFO memory is not usable. Driver failed to initialize."); + return ERR_PTR(-ENXIO); + } + return fifo; }