Tencent/matrix · warning · ParseException

cstime

Error message

${statBuffer}
cstime: ${num}

What it means

Same field-wise parser as above, but for field 17 (cstime, waited-for children's system time). The parser requires the token to pass isNumeric(); otherwise it throws ParseException embedding the entire stat buffer and the offending cstime token for diagnosis.

Solutions

1. Catch ParseException around parseWithBufferForPath and skip the sample.
2. Inspect the message's last line (the cstime token) and the stat layout; if fields are shifted, fix field counting after '(comm)'.
3. Retry the read — transient truncation during process exit is the most common cause.
4. Fall back to a more tolerant parser (e.g. parseWithSplits on the raw string) or drop the metric for the affected device.

Example fix

// before
stat.cstime = MatrixUtil.parseLong(num, 0);
// after (caller side)
try {
    stat = ProcStatUtil.parseWithBufferForPath(path);
} catch (ParseException e) {
    MatrixLog.w(TAG, "cstime parse failed: " + e.getMessage());
    stat = ProcStat.empty();
}

String raw = readProcStat(pid);
if (raw != null && raw.split("\\s+").length >= 18 && raw.split("\\s+")[17].matches("\\d+")) {
    stat = ProcStatUtil.parseWithBufferForPath(path);
}

static boolean isNumericToken(String s) { return s != null && s.matches("\\d+"); }

try {
    stat = ProcStatUtil.parseWithBufferForPath(path);
} catch (ParseException e) {
    Log.w(TAG, "cstime field invalid: " + e.getMessage());
    stat = ProcStat.empty();
}

When it happens

Trigger: parseWithBuffer encounters a non-numeric token at field 17 of /proc/<pid>/stat — torn/partial buffer from a dying process, misaligned field indexing caused by odd characters in comm, or truncated reads via parseWithBufferForPath.

Common situations: Sampling threads that exit during battery canary polling; devices whose kernels emit extra/missing stat fields; reading a stale snapshot written by another tool.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• cutime
• ProcStatReader error
• Matrix init, Matrix should not be null.
• you must init Matrix sdk first
• matrix init, application is null

AI-assisted analysis of Tencent/matrix@3b8293bd65 (2026-09-08). Data as JSON: /api/errors/ecdfc09d4b11250c. Report an issue: GitHub.

Appendix: source

Thrown at matrix/matrix-android/matrix-battery-canary/src/main/java/com/tencent/matrix/batterycanary/utils/ProcStatUtil.java:277

                        window++;
                    }
                    String num = safeBytesToString(statBuffer, readIdx, window);
                    if (!isNumeric(num)) {
                        throw new ParseException(safeBytesToString(statBuffer, 0, statBuffer.length) + "\ncutime: " + num);
                    }
                    stat.cutime = MatrixUtil.parseLong(num, 0);
                    break;
                }
                case 17: { // cstime
                    int readIdx = i, window = 0;
                    // seek next space
                    while (i < statBytes && !Character.isSpaceChar(statBuffer[i])) {
                        i++;
                        window++;
                    }
                    String num = safeBytesToString(statBuffer, readIdx, window);
                    if (!isNumeric(num)) {
                        throw new ParseException(safeBytesToString(statBuffer, 0, statBuffer.length) + "\ncstime: " + num);
                    }
                    stat.cstime = MatrixUtil.parseLong(num, 0);
                    break;
                }

                default:
                    i++;
            }
        }
        return stat;
    }

    @VisibleForTesting
    static ProcStat parseWithSplits(String cat) throws ParseException {
        ProcStat stat = new ProcStat();
        if (!TextUtils.isEmpty(cat)) {
            int index = cat.indexOf(")");
            if (index <= 0) throw new IllegalStateException(cat + " has not ')'");

View on GitHub (pinned to 3b8293bd65)