[PATCH xf86-video-amdgpu 1/2] Fix crash in PCI probe path (v3)

[Jammy Zhou]

The crash is caused by the NULL value returned by AMDGPUPTR(pScrn),
because the driverPrivate is not allocated yet in PciProbe phase,
and it is usually done in the PreInit phase.

Use pAMDGPUEnt->fd instead of info->dri2.drm_fd to avoid AMDGPUInfoPtr
related code in amdgpu_open_drm_master, so that the crash can be fixed.

v3: some more cleanup
v2: switch to pAMDGPUEnt->fd, and update the commit message

Signed-off-by: Jammy Zhou <Jammy.Zhou at amd.com>
---
 src/amdgpu_probe.c | 37 +++++++++++++------------------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/src/amdgpu_probe.c b/src/amdgpu_probe.c
index 481271b..f6e675c 100644
--- a/src/amdgpu_probe.c
+++ b/src/amdgpu_probe.c
@@ -147,24 +147,14 @@ static int amdgpu_kernel_open_fd(ScrnInfoPtr pScrn, struct pci_device *dev,
 	return fd;
 }
 
-static Bool amdgpu_open_drm_master(ScrnInfoPtr pScrn)
+static Bool amdgpu_open_drm_master(ScrnInfoPtr pScrn, AMDGPUEntPtr pAMDGPUEnt,
+				   struct pci_device *pci_dev, int entity_num)
 {
-	AMDGPUInfoPtr  info   = AMDGPUPTR(pScrn);
-	AMDGPUEntPtr pAMDGPUEnt = AMDGPUEntPriv(pScrn);
 	drmSetVersion sv;
 	int err;
 
-	if (pAMDGPUEnt->fd) {
-		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
-			   " reusing fd for second head\n");
-
-		info->drmmode.fd = info->dri2.drm_fd = pAMDGPUEnt->fd;
-		pAMDGPUEnt->fd_ref++;
-		return TRUE;
-	}
-
-	info->dri2.drm_fd = amdgpu_kernel_open_fd(pScrn, info->PciInfo, NULL);
-	if (info->dri2.drm_fd == -1)
+	pAMDGPUEnt->fd = amdgpu_kernel_open_fd(pScrn, pci_dev, NULL);
+	if (pAMDGPUEnt->fd == -1)
 		return FALSE;
 
 	/* Check that what we opened was a master or a master-capable FD,
@@ -175,18 +165,18 @@ static Bool amdgpu_open_drm_master(ScrnInfoPtr pScrn)
 	sv.drm_di_minor = 1;
 	sv.drm_dd_major = -1;
 	sv.drm_dd_minor = -1;
-	err = drmSetInterfaceVersion(info->dri2.drm_fd, &sv);
+	err = drmSetInterfaceVersion(pAMDGPUEnt->fd, &sv);
 	if (err != 0) {
 		xf86DrvMsg(pScrn->scrnIndex, X_ERROR,
 			   "[drm] failed to set drm interface version.\n");
-		drmClose(info->dri2.drm_fd);
+		drmClose(pAMDGPUEnt->fd);
 		return FALSE;
 	}
 
 	return TRUE;
 }
 
-static Bool amdgpu_get_scrninfo(int entity_num, void *pci_dev)
+static Bool amdgpu_get_scrninfo(int entity_num, struct pci_device *pci_dev)
 {
 	ScrnInfoPtr pScrn = NULL;
 	EntityInfoPtr pEnt;
@@ -236,11 +226,13 @@ static Bool amdgpu_get_scrninfo(int entity_num, void *pci_dev)
 		uint32_t minor_version;
 
 		pPriv->ptr = xnfcalloc(sizeof(AMDGPUEntRec), 1);
-		pAMDGPUEnt = pPriv->ptr;
+		if (!pPriv->ptr)
+			return FALSE;
 
-		if (amdgpu_open_drm_master(pScrn)) {
+		pAMDGPUEnt = pPriv->ptr;
+		if (!amdgpu_open_drm_master(pScrn, pAMDGPUEnt,
+					    pci_dev, entity_num))
 			goto error_fd;
-		}
 
 		pAMDGPUEnt->fd_ref = 1;
 
@@ -252,8 +244,6 @@ static Bool amdgpu_get_scrninfo(int entity_num, void *pci_dev)
 				   "amdgpu_device_initialize failed\n");
 			goto error_amdgpu;
 		}
-	} else {
-		pAMDGPUEnt = pPriv->ptr;
 	}
 
 	xf86SetEntityInstanceForScreen(pScrn, pEnt->index,
@@ -266,7 +256,6 @@ static Bool amdgpu_get_scrninfo(int entity_num, void *pci_dev)
 
 error_amdgpu:
 	drmClose(pAMDGPUEnt->fd);
-	pAMDGPUEnt->fd = 0;
 error_fd:
 	free(pPriv->ptr);
 	return FALSE;
@@ -276,7 +265,7 @@ static Bool
 amdgpu_pci_probe(DriverPtr pDriver,
 		 int entity_num, struct pci_device *device, intptr_t match_data)
 {
-	return amdgpu_get_scrninfo(entity_num, (void *)device);
+	return amdgpu_get_scrninfo(entity_num, device);
 }
 
 static Bool AMDGPUDriverFunc(ScrnInfoPtr scrn, xorgDriverFuncOp op, void *data)
-- 
1.9.1