[PATCH V2 1/2] drm/amdgpu: Fixed the defect of soft lock caused by infinite loop

yipechai YiPeng.Chai at amd.com
Sun Jan 30 07:11:39 UTC 2022


1. The infinite loop case only occurs on multiple cards support
   ras functions.
2. The explanation of root cause refer to commit 76641cbbf196
   ("drm/amdgpu: Add judgement to avoid infinite loop").
3. Create new node to manage each unique ras instance to guarantee
   each device .ras_list is completely independent.
4. Fixes: commit 7a6b8ab3231b51 ("drm/amdgpu: Unify ras block
   interface for each ras block").
5. The soft locked logs are as follows:
[  262.165690] CPU: 93 PID: 758 Comm: kworker/93:1 Tainted: G           OE     5.13.0-27-generic #29~20.04.1-Ubuntu
[  262.165695] Hardware name: Supermicro AS -4124GS-TNR/H12DSG-O-CPU, BIOS T20200717143848 07/17/2020
[  262.165698] Workqueue: events amdgpu_ras_do_recovery [amdgpu]
[  262.165980] RIP: 0010:amdgpu_ras_get_ras_block+0x86/0xd0 [amdgpu]
[  262.166239] Code: 68 d8 4c 8d 71 d8 48 39 c3 74 54 49 8b 45 38 48 85 c0 74 32 44 89 fa 44 89 e6 4c 89 ef e8 82 e4 9b dc 85 c0 74 3c 49 8b 46 28 <49> 8d 56 28 4d 89 f5 48 83 e8 28 48 39 d3 74 25 49 89 c6 49 8b 45
[  262.166243] RSP: 0018:ffffac908fa87d80 EFLAGS: 00000202
[  262.166247] RAX: ffffffffc1394248 RBX: ffff91e4ab8d6e20 RCX: ffffffffc1394248
[  262.166249] RDX: ffff91e4aa356e20 RSI: 000000000000000e RDI: ffff91e4ab8c0000
[  262.166252] RBP: ffffac908fa87da8 R08: 0000000000000007 R09: 0000000000000001
[  262.166254] R10: ffff91e4930b64ec R11: 0000000000000000 R12: 000000000000000e
[  262.166256] R13: ffff91e4aa356df8 R14: ffffffffc1394320 R15: 0000000000000003
[  262.166258] FS:  0000000000000000(0000) GS:ffff92238fb40000(0000) knlGS:0000000000000000
[  262.166261] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  262.166264] CR2: 00000001004865d0 CR3: 000000406d796000 CR4: 0000000000350ee0
[  262.166267] Call Trace:
[  262.166272]  amdgpu_ras_do_recovery+0x130/0x290 [amdgpu]
[  262.166529]  ? psi_task_switch+0xd2/0x250
[  262.166537]  ? __switch_to+0x11d/0x460
[  262.166542]  ? __switch_to_asm+0x36/0x70
[  262.166549]  process_one_work+0x220/0x3c0
[  262.166556]  worker_thread+0x4d/0x3f0
[  262.166560]  ? process_one_work+0x3c0/0x3c0
[  262.166563]  kthread+0x12b/0x150
[  262.166568]  ? set_kthread_struct+0x40/0x40
[  262.166571]  ret_from_fork+0x22/0x30

Signed-off-by: yipechai <YiPeng.Chai at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 37 ++++++++++++++++++++++---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h |  3 --
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index 9d7c778c1a2d..9b94c9c4960c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -75,6 +75,13 @@ const char *ras_mca_block_string[] = {
 	"mca_iohc",
 };
 
+struct amdgpu_ras_block_list {
+	/* ras block link */
+	struct list_head node;
+
+	struct amdgpu_ras_block_object *ras_obj;
+};
+
 const char *get_ras_block_str(struct ras_common_if *ras_block)
 {
 	if (!ras_block)
@@ -880,7 +887,8 @@ static struct amdgpu_ras_block_object *amdgpu_ras_get_ras_block(struct amdgpu_de
 					enum amdgpu_ras_block block, uint32_t sub_block_index)
 {
 	int loop_cnt = 0;
-	struct amdgpu_ras_block_object *obj, *tmp;
+	struct amdgpu_ras_block_list *node, *tmp;
+	struct amdgpu_ras_block_object *obj;
 
 	if (block >= AMDGPU_RAS_BLOCK__LAST)
 		return NULL;
@@ -888,7 +896,13 @@ static struct amdgpu_ras_block_object *amdgpu_ras_get_ras_block(struct amdgpu_de
 	if (!amdgpu_ras_is_supported(adev, block))
 		return NULL;
 
-	list_for_each_entry_safe(obj, tmp, &adev->ras_list, node) {
+	list_for_each_entry_safe(node, tmp, &adev->ras_list, node) {
+		if (!node->ras_obj) {
+			dev_warn(adev->dev, "Warning: abnormal ras list node.\n");
+			continue;
+		}
+
+		obj = node->ras_obj;
 		if (obj->ras_block_match) {
 			if (obj->ras_block_match(obj, block, sub_block_index) == 0)
 				return obj;
@@ -2527,6 +2541,7 @@ int amdgpu_ras_pre_fini(struct amdgpu_device *adev)
 
 int amdgpu_ras_fini(struct amdgpu_device *adev)
 {
+	struct amdgpu_ras_block_list *ras_node, *tmp;
 	struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
 
 	if (!adev->ras_enabled || !con)
@@ -2545,6 +2560,12 @@ int amdgpu_ras_fini(struct amdgpu_device *adev)
 	amdgpu_ras_set_context(adev, NULL);
 	kfree(con);
 
+	/* Clear ras blocks from ras_list and free ras block list node */
+	list_for_each_entry_safe(ras_node, tmp, &adev->ras_list, node) {
+		list_del(&ras_node->node);
+		kfree(ras_node);
+	}
+
 	return 0;
 }
 
@@ -2754,14 +2775,22 @@ int amdgpu_ras_reset_gpu(struct amdgpu_device *adev)
 int amdgpu_ras_register_ras_block(struct amdgpu_device *adev,
 		struct amdgpu_ras_block_object *ras_block_obj)
 {
+	struct amdgpu_ras_block_list *ras_node;
 	if (!adev || !ras_block_obj)
 		return -EINVAL;
 
 	if (!amdgpu_ras_asic_supported(adev))
 		return 0;
 
-	INIT_LIST_HEAD(&ras_block_obj->node);
-	list_add_tail(&ras_block_obj->node, &adev->ras_list);
+	ras_node = kzalloc(sizeof(*ras_node), GFP_KERNEL);
+	if (!ras_node) {
+		dev_err(adev->dev, "Failed to allocate ras_node!\n");
+		return -ENOMEM;
+	}
+
+	INIT_LIST_HEAD(&ras_node->node);
+	ras_node->ras_obj = ras_block_obj;
+	list_add_tail(&ras_node->node, &adev->ras_list);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
index a51a281bd91a..a55743b12d57 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
@@ -493,9 +493,6 @@ struct amdgpu_ras_block_object {
 
 	uint32_t sub_block_index;
 
-	/* ras block link */
-	struct list_head node;
-
 	int (*ras_block_match)(struct amdgpu_ras_block_object *block_obj,
 				enum amdgpu_ras_block block, uint32_t sub_block_index);
 	int (*ras_late_init)(struct amdgpu_device *adev, void *ras_info);
-- 
2.25.1



More information about the amd-gfx mailing list