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Deadlock: Out-of-Sequence Step Value
Time | Thread # |
| Action |
---|---|---|---|
0 | 3 | 0 | Thread 3 executes the first time: the predicate is |
1 | 2 | 0 | Thread 2 executes the first time: the predicate is |
2 | 4 | 0 | Thread 4 executes the first time: the predicate is |
3 | 0 | 0 | Thread 0 executes the first time: the predicate is |
4 | 1 | 1 | Thread 1 executes the first time: the predicate is |
5 | 3 | 2 | Thread 3 wakes up (scheduler choice): the predicate is |
6 | — | — | Thread exhaustion! There are no more threads to run, and a conditional variable signal is needed to wake up the others. |
This noncompliant code example violates the liveness property.
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Failing to preserve the thread safety and liveness of a program when using condition variables can lead to indefinite blocking and denial of service (DoS).
Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
---|---|---|---|---|---|
CON55-CPP | Low | Unlikely | Medium | P2 | L3 |
Automated Detection
Tool | Version | Checker | Description |
---|
CodeSonar |
| CONCURRENCY.BADFUNC.CNDSIGNAL | Use of Condition Variable Signal | ||||||
Helix QAC |
| C++1778, C++1779 |
Klocwork |
| CERT.CONC.UNSAFE_COND_VAR | |||||||
Parasoft C/ |
C++test |
|
| CERT_CPP-CON55-a | Do not use the 'notify_one()' function when multiple threads are waiting on the same condition variable | |||||||
Polyspace Bug Finder |
| Checks for multiple threads waiting for same condition variable (rule fully covered) |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
Bibliography
[IEEE Std 1003.1:2013] | XSH, System Interfaces, pthread_cond_broadcast XSH, System Interfaces, pthread_cond_signal |
[Lea 2000] |
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