Zepp-Hanzj opened a new pull request, #18980:
URL: https://github.com/apache/nuttx/pull/18980
## Summary
Fix two bugs in the allocation error paths of `mcp48xx_initialize()` and
`mcp47x6_initialize()`:
1. **Dead code** — when the first `kmm_malloc()` fails and `priv` is NULL,
the original code calls `free(priv)` which is a no-op on NULL. Remove
the dead call.
2. **Memory leak** — when the second `kmm_malloc()` fails (`dacdev`), the
original code returns NULL without freeing the already-allocated `priv`.
Add `kmm_free(priv)` before the return.
Both drivers share the identical pattern, so both are fixed in this commit.
## Impact
- [x] Impact on user: NO — fixes an internal resource-management bug only
visible in low-memory conditions.
- [x] Impact on build: NO
- [x] Impact on documentation: NO
- [x] Impact on security: NO — the leak is bounded (one allocation per
failed init call) but still worth fixing.
- [x] Impact on compatibility: NO
## Testing
### Source verification
Before (mcp48xx.c lines 343-356, mcp47x6.c lines 437-450):
```c
priv = kmm_malloc(sizeof(struct mcp48xx_dev_s));
if (priv == NULL)
{
aerr("ERROR: Failed to allocate mcp48xx_dev_s instance\n");
free(priv); /* dead code: priv is NULL here */
return NULL;
}
dacdev = kmm_malloc(sizeof(struct dac_dev_s));
if (dacdev == NULL)
{
aerr("ERROR: Failed to allocate dac_dev_s instance\n");
return NULL; /* BUG: priv is leaked */
}
```
After:
```c
priv = kmm_malloc(sizeof(struct mcp48xx_dev_s));
if (priv == NULL)
{
aerr("ERROR: Failed to allocate mcp48xx_dev_s instance\n");
return NULL; /* dead free(priv) removed */
}
dacdev = kmm_malloc(sizeof(struct dac_dev_s));
if (dacdev == NULL)
{
aerr("ERROR: Failed to allocate dac_dev_s instance\n");
kmm_free(priv); /* fix: free previously allocated priv */
return NULL;
}
```
### Validation
```
$ ./tools/checkpatch.sh -g HEAD
✔️ All checks pass.
```
The fix is purely in the error path and does not change any
successful execution flow.
Signed-off-by: hanzj <[email protected]>
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
