From: jsg <jsg@openbsd.org>
Date: Mon, 22 Jan 2024 02:54:33 +0000 (+0000)
Subject: drm/amdgpu: Fix cat debugfs amdgpu_regs_didt causes kernel null pointer
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=41d7f58f6fe190acb5a16e52bf758763e01eb640;p=openbsd

drm/amdgpu: Fix cat debugfs amdgpu_regs_didt causes kernel null pointer

From Lu Yao
61dfdb779048332546358ac1847f0bbb07367162 in linux-6.6.y/6.6.13
2161e09cd05a50d80736fe397145340d2e8f6c05 in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/amdgpu/amdgpu_debugfs.c b/sys/dev/pci/drm/amd/amdgpu/amdgpu_debugfs.c
index 05405da51e7..3f2126f9992 100644
--- a/sys/dev/pci/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/sys/dev/pci/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -638,6 +638,9 @@ static ssize_t amdgpu_debugfs_regs_didt_read(struct file *f, char __user *buf,
 	if (size & 0x3 || *pos & 0x3)
 		return -EINVAL;
 
+	if (!adev->didt_rreg)
+		return -EOPNOTSUPP;
+
 	r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
 	if (r < 0) {
 		pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
@@ -694,6 +697,9 @@ static ssize_t amdgpu_debugfs_regs_didt_write(struct file *f, const char __user
 	if (size & 0x3 || *pos & 0x3)
 		return -EINVAL;
 
+	if (!adev->didt_wreg)
+		return -EOPNOTSUPP;
+
 	r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
 	if (r < 0) {
 		pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);