[ZBX-10031] On Windows some thread local variables are actually not thread local Created: 2015 Oct 30 Updated: 2017 May 30 Resolved: 2015 Nov 24 |
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| Status: | Closed |
| Project: | ZABBIX BUGS AND ISSUES |
| Component/s: | Agent (G) |
| Affects Version/s: | 2.4.6 |
| Fix Version/s: | 3.0.0alpha5 |
| Type: | Incident report | Priority: | Trivial |
| Reporter: | Sandis Neilands (Inactive) | Assignee: | Unassigned |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | codequality, windows | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Environment: |
Windows Server 2008 |
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| Description |
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See sub-issue (123) in This is a regression since src/zabbix_agent/zabbix_agentd.c ZBX_THREAD_LOCAL unsigned char process_type = 255; /* ZBX_PROCESS_TYPE_UNKNOWN */ ZBX_THREAD_LOCAL int process_num; ZBX_THREAD_LOCAL int server_num = 0; src/zabbix_agent/listener.c, etc. extern unsigned char process_type, program_type; extern int server_num, process_num; According to Microsoft this should produce (compile time?) errors. We don't have neither errors, nor warnings in our build environment regarding this problem. You must use the thread attribute for the declaration and the definition of thread local data, regardless of whether the declaration and definition occur in the same file or separate files. For example, the following code generates an error: #define Thread __declspec( thread ) extern int tls_i; /* This generates an error, because the */ int Thread tls_i; /* declaration and the definition differ. */ This causes listener threads reusing the same number due to race condition during thread initialization when agent is started. |
| Comments |
| Comment by Sandis Neilands (Inactive) [ 2015 Nov 20 ] |
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Since these variables are used also in server it is a bit difficult to check if all relevant places were modified. One method to do that is:
Testing: print addresses of these variables from the relevant files. Before changes they are the same across all threads. After changes - these are thread local variables with different addresses. Tested on Windows 8.1 64bit with build targeting Windows Server 2008 64bit. Fixed in development branch svn://svn.zabbix.com/branches/dev/ZBX-10031 . |
| Comment by Andris Zeila [ 2015 Nov 23 ] |
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Successfully tested |
| Comment by Sandis Neilands (Inactive) [ 2015 Nov 23 ] |
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Released in:
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