From: I Hsin Cheng richard120310@gmail.com
[ Upstream commit 5fb3878216aece471af030b33a9fbef3babd8617 ]
Initialize "ret" with "-EINVAL" to handle cases where "strstr()" for "codec_dai->component->name_prefix" doesn't find "-1" nor "-2". In that case "name_prefix" is invalid because for current implementation it's expected to have either "-1" or "-2" in it. (Maybe "-3", "-4" and so on in the future.)
Link: https://scan5.scan.coverity.com/#/project-view/36179/10063?selectedIssue=162... Signed-off-by: I Hsin Cheng richard120310@gmail.com Link: https://patch.msgid.link/20250505185423.680608-1-richard120310@gmail.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org ---
Based on my analysis of the commit and the codebase context, I can now provide a comprehensive assessment: **YES** This commit should be backported to stable kernel trees. ## Extensive Analysis ### Nature of the Bug The commit addresses a classic uninitialized variable bug in `asoc_sdw_rt_amp_spk_rtd_init()` in `sound/soc/sdw_utils/soc_sdw_rt_amp.c`. The function declares `int ret;` but only conditionally assigns values to it within a loop: ```c for_each_rtd_codec_dais(rtd, i, codec_dai) { if (strstr(codec_dai->component->name_prefix, "-1")) ret = snd_soc_dapm_add_routes(&card->dapm, rt_amp_map, 2); else if (strstr(codec_dai->component->name_prefix, "-2")) ret = snd_soc_dapm_add_routes(&card->dapm, rt_amp_map + 2, 2); } return ret; ``` ### When the Bug Manifests The bug occurs when: 1. `codec_dai->component->name_prefix` doesn't contain "-1" OR "-2" 2. Both `strstr()` calls return NULL, causing neither branch to execute 3. The function returns an uninitialized `ret` value, leading to unpredictable behavior ### Historical Context From the git blame analysis, this bug was introduced in commit `84e0a19adb73d` (May 9, 2024) by Bard Liao when adding a dai parameter to rtd_init callbacks. The commit changed the variable name from `dai` to `codec_dai` to avoid conflicts, but failed to initialize `ret` properly for the edge case. ### Code Analysis The fix is simple and correct: - **Before**: `int ret;` (uninitialized) - **After**: `int ret = -EINVAL;` (initialized with appropriate error code) The `-EINVAL` choice is appropriate because: 1. If name_prefix lacks "-1" or "-2", it indicates an invalid configuration for current implementation 2. The commit message explicitly states this expectation 3. `-EINVAL` is the standard Linux kernel error for invalid arguments ### Static Analysis Context The commit message references Coverity scan ID 1627120, indicating this was caught by static analysis tools. This is a legitimate bug that could cause: - Random return values leading to unpredictable behavior - Potential system instability in audio subsystem - Difficult-to-debug intermittent failures ### Backport Suitability Analysis **✅ Meets Stable Tree Criteria:** 1. **Important Bug Fix**: Fixes a real bug that can cause unpredictable behavior in the audio subsystem 2. **Small and Contained**: Single line change, minimal risk of introducing regressions 3. **No Side Effects**: Only affects the error path when name_prefix is invalid 4. **No Architectural Changes**: Pure bug fix with no design changes 5. **Subsystem Confined**: Limited to ASoC Intel SDW utils subsystem 6. **Clear Benefit**: Prevents undefined behavior and ensures deterministic error handling **Risk Assessment**: **VERY LOW** - Single line initialization change - Only affects error/edge case paths - No functional logic changes - Well- understood fix pattern **Impact**: **MODERATE** - Affects Intel SoundWire audio configurations - Could prevent audio system failures on affected hardware - Improves system reliability and debuggability ### Comparison with Similar Commits The provided examples show that simple NULL check additions (Similar Commit #1) and small contained bug fixes are consistently marked as "YES" for backporting. This commit follows the same pattern - it's a small, contained fix for a legitimate bug with minimal risk. This commit exemplifies the ideal stable tree candidate: it fixes a real bug, is minimal in scope, has no risk of regression, and improves system reliability.
sound/soc/sdw_utils/soc_sdw_rt_amp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/sdw_utils/soc_sdw_rt_amp.c b/sound/soc/sdw_utils/soc_sdw_rt_amp.c index 0538c252ba69b..83c2368170cb5 100644 --- a/sound/soc/sdw_utils/soc_sdw_rt_amp.c +++ b/sound/soc/sdw_utils/soc_sdw_rt_amp.c @@ -190,7 +190,7 @@ int asoc_sdw_rt_amp_spk_rtd_init(struct snd_soc_pcm_runtime *rtd, struct snd_soc const struct snd_soc_dapm_route *rt_amp_map; char codec_name[CODEC_NAME_SIZE]; struct snd_soc_dai *codec_dai; - int ret; + int ret = -EINVAL; int i;
rt_amp_map = get_codec_name_and_route(dai, codec_name);