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[[!meta title="libpthread: pthread_key_create, reuse"]]

IRC, FreeNode, #hurd, 2011-07-02

[[!tag open_issue_libpthread]]

    < pinotree> hm, maybe i found a libpthread bug
    * pinotree tries a testcase
    < pinotree> yesssss, found the bug :)
    < pinotree> youpi: it's a problem of the key reuse in pthread_key_create()
    < youpi> it doesn't reset it?
    < youpi> were you looking at the licq issue?
    < pinotree> no, gtest
    < youpi> k
    < youpi> licq has a failing threadspecific issue
    < youpi> [  FAILED  ] ThreadSpecificData.dataDeletedWhenThreadExits
    < pinotree> basically, pthread_key_delete() does not delete the key values
      from the "thread_specifics" ihash
    < pinotree> but those were new keys, so i'm not sure it is allowed to
      return values of previous keys?
    < pinotree> after all, the actual key value is an implementation detail,
      applications shouldn't care about it being reused
    < pinotree> (imho)
    < youpi> Upon key creation, the value NULL shall be associated with the new
      key in all active threads.
    < youpi> ok, so we have to clear it in all threads
    < youpi> that's a pity
    < pinotree> or just remove the entry from the hash on key removal
    < youpi> pinotree: from all the hashes, you mean?
    < pinotree> youpi: from how i see it, adding a snippet like
      http://paste.debian.net/121690/ in pthread_key_delete() should do the job
    < youpi> that only drops from the current thread
    < pinotree> ah hm, other threads
    < youpi> we need to drop from all  threads
    < youpi> that's the pity part
    < pinotree> youpi: the licq case could look like a similar issue, at a
      veeery quick glance

Test program: [[pthread_key_create_reuse.c]]