[v3 3/6] drm/amdgpu: fix use after free bug related to amdgpu_driver_release_kms()

Jiang Liu gerry at linux.alibaba.com
Wed Jan 8 08:56:01 UTC 2025


If some GPU device failed to probe, `rmmod amdgpu` will trigger a use
after free bug related to amdgpu_driver_release_kms() as:
2024-12-26 16:17:45 [16002.085540] BUG: kernel NULL pointer dereference, address: 0000000000000000
2024-12-26 16:17:45 [16002.093792] #PF: supervisor read access in kernel mode
2024-12-26 16:17:45 [16002.099993] #PF: error_code(0x0000) - not-present page
2024-12-26 16:17:45 [16002.106188] PGD 0 P4D 0
2024-12-26 16:17:45 [16002.109464] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
2024-12-26 16:17:45 [16002.115372] CPU: 2 PID: 14375 Comm: rmmod Kdump: loaded Tainted: G        W   E      6.10.0+ #2
2024-12-26 16:17:45 [16002.125577] Hardware name: Alibaba Alibaba Cloud ECS/Alibaba Cloud ECS, BIOS 3.0.ES.AL.P.087.05 04/07/2024
2024-12-26 16:17:45 [16002.136858] RIP: 0010:drm_sched_fini+0x3f/0xe0 [gpu_sched]
2024-12-26 16:17:45 [16002.143463] Code: 60 c6 87 be 00 00 00 01 e8 ce e0 90 d8 48 8d bb 80 00 00 00 e8 c2 e0 90 d8 8b 43 20 85 c0 74 51 45 31 e4 48 8b
43 28 4d 63 ec <4a> 8b 2c e8 48 89 ef e8 f5 0e 59 d9 48 8b 45 10 48 8d 55 10 48 39
2024-12-26 16:17:45 [16002.164992] RSP: 0018:ffffb570dbbb7da8 EFLAGS: 00010246
2024-12-26 16:17:45 [16002.171316] RAX: 0000000000000000 RBX: ffff96b0fdadc878 RCX: 0000000000000000
2024-12-26 16:17:46 [16002.179784] RDX: 000fffffffe00000 RSI: 0000000000000000 RDI: ffff96b0fdadc8f8
2024-12-26 16:17:46 [16002.188252] RBP: ffff96b0fdadc800 R08: ffff97abbd035040 R09: ffffffff9ac52540
2024-12-26 16:17:46 [16002.196722] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
2024-12-26 16:17:46 [16002.205179] R13: 0000000000000000 R14: ffff96b0fdadfc00 R15: 0000000000000000
2024-12-26 16:17:46 [16002.213648] FS:  00007f2737000740(0000) GS:ffff97abbd100000(0000) knlGS:0000000000000000
2024-12-26 16:17:46 [16002.223189] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
2024-12-26 16:17:46 [16002.230103] CR2: 0000000000000000 CR3: 000000011be3a005 CR4: 0000000000f70ef0
2024-12-26 16:17:46 [16002.238581] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
2024-12-26 16:17:46 [16002.247053] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
e024se+0x3c/0x90 [amdxcp]
2024-12-26 16:17:46 [16002.337645]  __do_sys_delete_module.constprop.0+0x176/0x310
2024-12-26 16:17:46 [16002.344324]  do_syscall_64+0x5d/0x170
2024-12-26 16:17:46 [16002.348858]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
2024-12-26 16:17:46 [16002.354956] RIP: 0033:0x7f2736a620cb-12-26

Fix it by removing xcp drm devices when failed to probe GPU devices.

Signed-off-by: Jiang Liu <gerry at linux.alibaba.com>
Tested-by: Shuo Liu <shuox.liu at linux.alibaba.com>
Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c    |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c    | 47 +++++++++++++++++++---
 drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h    |  4 +-
 5 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 5ff53a3b9851..510074a9074e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -6682,7 +6682,7 @@ void amdgpu_device_halt(struct amdgpu_device *adev)
 	struct pci_dev *pdev = adev->pdev;
 	struct drm_device *ddev = adev_to_drm(adev);
 
-	amdgpu_xcp_dev_unplug(adev);
+	amdgpu_xcp_dev_deregister(adev);
 	drm_dev_unplug(ddev);
 
 	amdgpu_irq_disable_all(adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 62de668e9ff8..41d1b06be600 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2435,7 +2435,7 @@ amdgpu_pci_remove(struct pci_dev *pdev)
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct amdgpu_device *adev = drm_to_adev(dev);
 
-	amdgpu_xcp_dev_unplug(adev);
+	amdgpu_xcp_dev_deregister(adev);
 	amdgpu_gmc_prepare_nps_mode_change(adev);
 	drm_dev_unplug(dev);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index d2a046736edd..be9147eb8308 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -1508,6 +1508,7 @@ void amdgpu_driver_release_kms(struct drm_device *dev)
 	struct amdgpu_device *adev = drm_to_adev(dev);
 
 	amdgpu_device_fini_sw(adev);
+	amdgpu_xcp_mgr_fini(adev);
 	pci_set_drvdata(adev->pdev, NULL);
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
index e209b5e101df..62dd5287808b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
@@ -283,6 +283,33 @@ static int amdgpu_xcp_dev_alloc(struct amdgpu_device *adev)
 	return 0;
 }
 
+static void amdgpu_xcp_dev_free(struct amdgpu_device *adev)
+{
+	struct drm_device *p_ddev;
+	int i;
+
+	if (!adev->xcp_mgr)
+		return;
+
+	for (i = 1; i < MAX_XCP; i++) {
+		if (!adev->xcp_mgr->xcp[i].ddev)
+			break;
+
+		// Restore and free the original drm_device.
+		p_ddev = adev->xcp_mgr->xcp[i].ddev;
+		p_ddev->render->dev = adev->xcp_mgr->xcp[i].rdev;
+		p_ddev->primary->dev = adev->xcp_mgr->xcp[i].pdev;
+		p_ddev->driver =  adev->xcp_mgr->xcp[i].driver;
+		p_ddev->vma_offset_manager = adev->xcp_mgr->xcp[i].vma_offset_manager;
+		amdgpu_xcp_drm_dev_free(p_ddev);
+
+		adev->xcp_mgr->xcp[i].ddev = NULL;
+	}
+
+	adev->xcp_mgr->xcp->ddev = NULL;
+}
+
+
 int amdgpu_xcp_mgr_init(struct amdgpu_device *adev, int init_mode,
 			int init_num_xcps,
 			struct amdgpu_xcp_mgr_funcs *xcp_funcs)
@@ -310,6 +337,13 @@ int amdgpu_xcp_mgr_init(struct amdgpu_device *adev, int init_mode,
 	return amdgpu_xcp_dev_alloc(adev);
 }
 
+void amdgpu_xcp_mgr_fini(struct amdgpu_device *adev)
+{
+	amdgpu_xcp_dev_free(adev);
+	kfree(adev->xcp_mgr);
+	adev->xcp_mgr = NULL;
+}
+
 int amdgpu_xcp_get_partition(struct amdgpu_xcp_mgr *xcp_mgr,
 			     enum AMDGPU_XCP_IP_BLOCK ip, int instance)
 {
@@ -359,12 +393,14 @@ int amdgpu_xcp_dev_register(struct amdgpu_device *adev,
 		ret = drm_dev_register(adev->xcp_mgr->xcp[i].ddev, ent->driver_data);
 		if (ret)
 			return ret;
+
+		adev->xcp_mgr->xcp[i].registered = true;
 	}
 
 	return 0;
 }
 
-void amdgpu_xcp_dev_unplug(struct amdgpu_device *adev)
+void amdgpu_xcp_dev_deregister(struct amdgpu_device *adev)
 {
 	struct drm_device *p_ddev;
 	int i;
@@ -377,11 +413,10 @@ void amdgpu_xcp_dev_unplug(struct amdgpu_device *adev)
 			break;
 
 		p_ddev = adev->xcp_mgr->xcp[i].ddev;
-		drm_dev_unplug(p_ddev);
-		p_ddev->render->dev = adev->xcp_mgr->xcp[i].rdev;
-		p_ddev->primary->dev = adev->xcp_mgr->xcp[i].pdev;
-		p_ddev->driver =  adev->xcp_mgr->xcp[i].driver;
-		p_ddev->vma_offset_manager = adev->xcp_mgr->xcp[i].vma_offset_manager;
+		if (adev->xcp_mgr->xcp[i].registered) {
+			drm_dev_unplug(p_ddev);
+			adev->xcp_mgr->xcp[i].registered = false;
+		}
 	}
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h
index b63f53242c57..be22d4398463 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h
@@ -101,6 +101,7 @@ struct amdgpu_xcp {
 	uint8_t id;
 	uint8_t mem_id;
 	bool valid;
+	bool registered;
 	atomic_t	ref_cnt;
 	struct drm_device *ddev;
 	struct drm_device *rdev;
@@ -155,6 +156,7 @@ int amdgpu_xcp_resume(struct amdgpu_xcp_mgr *xcp_mgr, int xcp_id);
 
 int amdgpu_xcp_mgr_init(struct amdgpu_device *adev, int init_mode,
 			int init_xcps, struct amdgpu_xcp_mgr_funcs *xcp_funcs);
+void amdgpu_xcp_mgr_fini(struct amdgpu_device *adev);
 int amdgpu_xcp_init(struct amdgpu_xcp_mgr *xcp_mgr, int num_xcps, int mode);
 int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, u32 flags);
 int amdgpu_xcp_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, int mode);
@@ -168,7 +170,7 @@ int amdgpu_xcp_get_inst_details(struct amdgpu_xcp *xcp,
 
 int amdgpu_xcp_dev_register(struct amdgpu_device *adev,
 				const struct pci_device_id *ent);
-void amdgpu_xcp_dev_unplug(struct amdgpu_device *adev);
+void amdgpu_xcp_dev_deregister(struct amdgpu_device *adev);
 int amdgpu_xcp_open_device(struct amdgpu_device *adev,
 			   struct amdgpu_fpriv *fpriv,
 			   struct drm_file *file_priv);
-- 
2.43.5



More information about the amd-gfx mailing list