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If we're going to have a non-panic check for held_lwlocks[] overrun, 

it must occur *before* we get into the critical state of holding a
lock we have no place to record.  Per discussion with Qingqing Zhou.
This commit is contained in:
Tom Lane 2005-04-08 14:18:35 +00:00
parent e794dfa511
commit badb83f9ec
1 changed files with 9 additions and 5 deletions
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14
src/backend/storage/lmgr/lwlock.c
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@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.26 2005/04/08 03:43:54 tgl Exp $ * $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.27 2005/04/08 14:18:35 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -213,6 +213,10 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
*/ */
Assert(!(proc == NULL && IsUnderPostmaster)); Assert(!(proc == NULL && IsUnderPostmaster));
/* Ensure we will have room to remember the lock */
if (num_held_lwlocks >= MAX_SIMUL_LWLOCKS)
elog(ERROR, "too many LWLocks taken");
/* /*
* Lock out cancel/die interrupts until we exit the code section * Lock out cancel/die interrupts until we exit the code section
* protected by the LWLock. This ensures that interrupts will not * protected by the LWLock. This ensures that interrupts will not
@ -328,8 +332,6 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
SpinLockRelease_NoHoldoff(&lock->mutex); SpinLockRelease_NoHoldoff(&lock->mutex);
/* Add lock to list of locks held by this backend */ /* Add lock to list of locks held by this backend */
if (num_held_lwlocks >= MAX_SIMUL_LWLOCKS)
elog(ERROR, "too many LWLocks taken");
held_lwlocks[num_held_lwlocks++] = lockid; held_lwlocks[num_held_lwlocks++] = lockid;
/* /*
@ -354,6 +356,10 @@ LWLockConditionalAcquire(LWLockId lockid, LWLockMode mode)
PRINT_LWDEBUG("LWLockConditionalAcquire", lockid, lock); PRINT_LWDEBUG("LWLockConditionalAcquire", lockid, lock);
/* Ensure we will have room to remember the lock */
if (num_held_lwlocks >= MAX_SIMUL_LWLOCKS)
elog(ERROR, "too many LWLocks taken");
/* /*
* Lock out cancel/die interrupts until we exit the code section * Lock out cancel/die interrupts until we exit the code section
* protected by the LWLock. This ensures that interrupts will not * protected by the LWLock. This ensures that interrupts will not
@ -398,8 +404,6 @@ LWLockConditionalAcquire(LWLockId lockid, LWLockMode mode)
else else
{ {
/* Add lock to list of locks held by this backend */ /* Add lock to list of locks held by this backend */
if (num_held_lwlocks >= MAX_SIMUL_LWLOCKS)
elog(ERROR, "too many LWLocks taken");
held_lwlocks[num_held_lwlocks++] = lockid; held_lwlocks[num_held_lwlocks++] = lockid;
} }