[PATCH] gpu: host1x: skip trace payloads after mapping failure

[Slavin Liu]

Command tracing maps the original buffer independently of job pinning.
An ERR_PTR mapping is non-NULL but is not readable. Skip payload capture
and unmapping when this diagnostic mapping fails.

Detected by static analysis and reviewed with AI-assisted source auditing.

Fixes: 3f257bc63c0d ("drm/tegra: gem: Do not return NULL in tegra_bo_mmap()")
Assisted-by: LLM
Signed-off-by: Slavin Liu <bolin....@seu.edu.cn>
---
 drivers/gpu/host1x/hw/channel_hw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/host1x/hw/channel_hw.c 
b/drivers/gpu/host1x/hw/channel_hw.c
index a8251ec0810c..19949c99c427 100644
--- a/drivers/gpu/host1x/hw/channel_hw.c
+++ b/drivers/gpu/host1x/hw/channel_hw.c
@@ -28,7 +28,7 @@ static void trace_write_gather(struct host1x_cdma *cdma, 
struct host1x_bo *bo,
        if (host1x_debug_trace_cmdbuf)
                mem = host1x_bo_mmap(bo);
 
-       if (mem) {
+       if (!IS_ERR_OR_NULL(mem)) {
                u32 i;
                /*
                 * Write in batches of 128 as there seems to be a limit