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Avoid deadlock.

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This commit is contained in:
Bodo Möller 1999-11-12 16:20:30 +00:00
parent 01aad2c80a
commit 47d216940c
1 changed files with 15 additions and 1 deletions
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16
crypto/mem.c
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@ -137,9 +137,23 @@ int CRYPTO_mem_ctrl(int mode)
if (mh_mode & CRYPTO_MEM_CHECK_ON)
{
mh_mode&= ~CRYPTO_MEM_CHECK_ENABLE;
if (disabling_thread != CRYPTO_thread_id())
if (disabling_thread != CRYPTO_thread_id()) /* otherwise we already have the MALLOC2 lock */
{
/* Long-time lock CRYPTO_LOCK_MALLOC2 must not be claimed while
* we're holding CRYPTO_LOCK_MALLOC, or we'll deadlock if
* somebody else holds CRYPTO_LOCK_MALLOC2 (and cannot release it
* because we block entry to this function).
* Give them a chance, first, and then claim the locks in
* appropriate order (long-time lock first).
*/
CRYPTO_w_unlock(CRYPTO_LOCK_MALLOC);
/* Note that after we have waited for CRYPTO_LOCK_MALLOC2
* and CRYPTO_LOCK_MALLOC, we'll still be in the right
* "case" and "if" branch because MemCheck_start and
* MemCheck_stop may never be used while there are multiple
* OpenSSL threads. */
CRYPTO_w_lock(CRYPTO_LOCK_MALLOC2);
CRYPTO_w_lock(CRYPTO_LOCK_MALLOC);
disabling_thread=CRYPTO_thread_id();
}
}