Prevent NULL pointer dereference in case when radeon_ring_fini() did it's job.
Reading of r100_cp_ring_info and radeon_ring_gfx debugfs entries will lead to a KP if ring buffer was deallocated, e.g. on failed ring test.
Seen on PA-RISC machine having "radeon: ring test failed (scratch(0x8504)=0xCAFEDEAD)" issue.
Signed-off-by: Alex Ivanov <gnidorah@xxxxxxxxx>
---
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index 2417571..413cdd1 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -2933,10 +2933,11 @@ static int r100_debugfs_cp_ring_info(struct seq_file *m, void *data)
seq_printf(m, "CP_RB_RPTR 0x%08x\n", rdp);
seq_printf(m, "%u free dwords in ring\n", ring->ring_free_dw);
seq_printf(m, "%u dwords in ring\n", count);
- for (j = 0; j <= count; j++) {
- i = (rdp + j) & ring->ptr_mask;
- seq_printf(m, "r[%04d]=0x%08x\n", i, ring->ring[i]);
- }
+ if (ring->ready)
+ for (j = 0; j <= count; j++) {
+ i = (rdp + j) & ring->ptr_mask;
+ seq_printf(m, "r[%04d]=0x%08x\n", i, ring->ring[i]);
+ }
return 0;
}
diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index 46a25f0..a890756 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -839,10 +839,11 @@ static int radeon_debugfs_ring_info(struct seq_file *m, void *data)
* packet that is the root issue
*/
i = (ring->rptr + ring->ptr_mask + 1 - 32) & ring->ptr_mask;
- for (j = 0; j <= (count + 32); j++) {
- seq_printf(m, "r[%5d]=0x%08x\n", i, ring->ring[i]);
- i = (i + 1) & ring->ptr_mask;
- }
+ if (ring->ready)
+ for (j = 0; j <= (count + 32); j++) {
+ seq_printf(m, "r[%5d]=0x%08x\n", i, ring->ring[i]);
+ i = (i + 1) & ring->ptr_mask;
+ }
return 0;
}
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