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 comprehensive analysis of this commit, I can now provide my backport recommendation: **YES** This commit should be backported to stable kernel trees. Here's my extensive analysis: ## Bug Description and Analysis The commit fixes a critical bug in the `asoc_sdw_rt_amp_spk_rtd_init()` function in `sound/soc/sdw_utils/soc_sdw_rt_amp.c`. The issue is that the `ret` variable is declared but never initialized, and in certain execution paths, it may be returned uninitialized. ### Specific Problem Details 1. **Uninitialized Variable Issue**: The `ret` variable is declared on line 193 but never given an initial value. 2. **Problematic Code Path**: In the `for_each_rtd_codec_dais()` loop (lines 204-209), `ret` is only assigned a value if `strstr()` finds either "-1" or "-2" in the `codec_dai->component->name_prefix`. However, if neither condition is met, `ret` remains uninitialized. 3. **Return of Garbage Value**: When the function reaches `return ret;` on line 211, if neither condition in the loop was satisfied, the function returns an uninitialized value, which could be any random memory content. ### Why This Is a Serious Bug 1. **Unpredictable Behavior**: The function may return success (0) or failure (non-zero) randomly depending on stack contents, leading to inconsistent system behavior. 2. **Audio Subsystem Impact**: The function is used as an `rtd_init` callback for multiple Realtek audio amplifier codecs (rt1308, rt1316, rt1318, rt1320) as evidenced by the codec info list in `soc_sdw_utils.c`. 3. **Error Propagation**: The return value is checked in `asoc_sdw_rtd_init()` and propagated upward - a garbage positive value would cause audio initialization to fail unexpectedly. ### Evidence from Code Analysis The function is called via the `rtd_init` callback mechanism: ```c if (codec_info->dais[dai_index].rtd_init) { ret = codec_info->dais[dai_index].rtd_init(rtd, dai); if (ret) return ret; // Failure propagated upward } ``` The fix correctly initializes `ret = -EINVAL` to handle the case where the `name_prefix` doesn't contain the expected "-1" or "-2" suffixes, which indicates an invalid configuration that should properly return an error. ### Characteristics Supporting Backport 1. **Clear Bug Fix**: This is a straightforward bug fix with no new features or architectural changes. 2. **Minimal Risk**: The change is one line adding initialization - extremely low risk of introducing regressions. 3. **Wide Hardware Impact**: Affects multiple Realtek audio amplifier codecs used in Intel SoundWire configurations. 4. **Stable Tree Compatible**: Bug was introduced in v6.10 (commit 84e0a19adb73d), making it applicable to stable kernels from v6.10 onward. 5. **Static Analysis Found**: The bug was found by Coverity static analysis, indicating it's a real issue that could manifest in practice. 6. **User Impact**: Audio hardware initialization failures can significantly impact user experience, especially on laptops and embedded systems using these codecs. This commit perfectly fits the stable kernel criteria: it fixes an important bug, has minimal risk, is contained to a specific subsystem, and addresses undefined behavior that could cause random failures in audio hardware initialization.
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 6951dfb565263..b3d6ca2499734 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);