Bug 100490

Summary: pthread_detach in tls lib fails with more than 5 threads
Product: [Retired] Red Hat Linux Reporter: Sebastien Hensgen <hensgen>
Component: glibcAssignee: Jakub Jelinek <jakub>
Status: CLOSED NOTABUG QA Contact: Brian Brock <bbrock>
Severity: high Docs Contact:
Priority: medium    
Version: 9CC: fweimer
Target Milestone: ---   
Target Release: ---   
Hardware: i686   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2003-07-22 21:49:58 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
The code to compile and run to see the Segfmentation faults. none

Description Sebastien Hensgen 2003-07-22 21:24:20 UTC 
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225

Description of problem:
The tls implementation of pthread_detach leads to a segmentation fault.

After having start 5 threads, or more, exited from all the 5 threads,
the first call to pthread_detach leads to a segmentation fault.
With less than 5 threads, evithing seems ok. It seems it only crashes with 5 or
more.

There is no problem anymore if the executable links on /lib/pthread.so istead of
/lib/tls/libpthread.so.0

Version-Release number of selected component (if applicable):
glib-2.3.2-27.9

How reproducible:
Always

Steps to Reproduce:
1.Compile (g++ -l pthread main.cpp) the code in attachment.
2.Execute it.
    

Actual Results:  Thread launched.
Thread launched.
Thread launched.
Thread launched.
Thread launched.
Segmentation fault

Expected Results:  Thread launched.
Thread launched.
Thread launched.
Thread launched.
Thread launched.
Thread #0 detached.
Thread #1 detached.
Thread #2 detached.
Thread #3 detached.
Thread #4 detached.

Additional info:

Rename /lib/tls into /lib/tls_ and the Segmentation fault desappears.
Comment 1 Sebastien Hensgen 2003-07-22 21:27:59 UTC 
Created attachment 93061 [details]
The code to compile and run to see the Segfmentation faults.

The code launch <n> threads, wait for they all exited, and call pthread_detach
on each of them.
<n> can be given as a parameter to the binary. 5 is default.
Comment 2 Jakub Jelinek 2003-07-22 21:49:58 UTC 
Your testcase is bogus. A pthread_t handle is not valid after pthread_join,
it is like accessing memory after free or FILE * stream after fclose.
The implementation may fail with EINVAL if it detects invalid handle, but
is not required to do so. Doing so in all cases would be extremely expensive,
would mean on every pthread_detach walking down all currently joinable threads
and compare pthread_detach argument with them. Furthermore, even that doesn't
handle the case when a pthread_t handle is reused for another thread after
pthread_join (h1, ...); pthread_create (&h2, ...); pthread_detach (h1);
if h2 == h1.