drm/radeon: Make r100_cp_ring_info() and radeon_ring_gfx() safe (v2)
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.
v2: agd5f: add some parens around ring->ready check
Signed-off-by: Alex Ivanov <gnidorah@p0n4ik.tk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index 2417571..d713330 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -2933,9 +2933,11 @@
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;
}