From fae6241960a2c0df8df5d83001ce298228f4cbf2 Mon Sep 17 00:00:00 2001 From: "yizhi.fzh" Date: Thu, 4 Jan 2024 22:19:50 +0800 Subject: [PATCH v2 2/2] Disallow [LW]LockAcquire when holding a spin lock-file-mode Spinlocks are intended for *very* short-term locks, but sometimes it is misused, this commit guards no [LW]LockAcquire should be called when holding a spin lock. --- src/backend/storage/buffer/bufmgr.c | 1 + src/backend/storage/lmgr/lock.c | 2 ++ src/backend/storage/lmgr/lwlock.c | 2 ++ src/backend/utils/init/globals.c | 1 + src/include/storage/buf_internals.h | 1 + src/include/storage/spin.h | 24 ++++++++++++++++++++++-- 6 files changed, 29 insertions(+), 2 deletions(-) diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 9f9d3f24ac..d2534ee9aa 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -5419,6 +5419,7 @@ LockBufHdr(BufferDesc *desc) perform_spin_delay(&delayStatus); } finish_spin_delay(&delayStatus); + START_SPIN_LOCK(); return old_buf_state | BM_LOCKED; } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index b8c57b3e16..0710adbef8 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -776,6 +776,8 @@ LockAcquireExtended(const LOCKTAG *locktag, bool found_conflict; bool log_lock = false; + Assert(SpinLockCount == 0); + if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods)) elog(ERROR, "unrecognized lock method: %d", lockmethodid); lockMethodTable = LockMethods[lockmethodid]; diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c index 315a78cda9..5709cadcd5 100644 --- a/src/backend/storage/lmgr/lwlock.c +++ b/src/backend/storage/lmgr/lwlock.c @@ -1205,6 +1205,8 @@ LWLockAcquire(LWLock *lock, LWLockMode mode) Assert(mode == LW_SHARED || mode == LW_EXCLUSIVE); + Assert(SpinLockCount == 0); + PRINT_LWDEBUG("LWLockAcquire", lock, mode); #ifdef LWLOCK_STATS diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c index 60bc1217fb..125dc53375 100644 --- a/src/backend/utils/init/globals.c +++ b/src/backend/utils/init/globals.c @@ -40,6 +40,7 @@ volatile sig_atomic_t IdleStatsUpdateTimeoutPending = false; volatile uint32 InterruptHoldoffCount = 0; volatile uint32 QueryCancelHoldoffCount = 0; volatile uint32 CritSectionCount = 0; +volatile uint32 SpinLockCount = 0; int MyProcPid; pg_time_t MyStartTime; diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h index 2c4fd92e39..be2d090308 100644 --- a/src/include/storage/buf_internals.h +++ b/src/include/storage/buf_internals.h @@ -363,6 +363,7 @@ UnlockBufHdr(BufferDesc *desc, uint32 buf_state) { pg_write_barrier(); pg_atomic_write_u32(&desc->state, buf_state & (~BM_LOCKED)); + END_SPIN_LOCK(); } /* in bufmgr.c */ diff --git a/src/include/storage/spin.h b/src/include/storage/spin.h index 5d809cc980..c1b96a047f 100644 --- a/src/include/storage/spin.h +++ b/src/include/storage/spin.h @@ -56,12 +56,32 @@ #include "storage/pg_sema.h" #endif +extern PGDLLIMPORT volatile uint32 SpinLockCount; + +#define START_SPIN_LOCK() (SpinLockCount++) +#define END_SPIN_LOCK() \ +do { \ + Assert(SpinLockCount > 0); \ + SpinLockCount--; \ +} while(0) #define SpinLockInit(lock) S_INIT_LOCK(lock) -#define SpinLockAcquire(lock) S_LOCK(lock) +#define SpinLockAcquire(lock) \ + do \ + { \ + S_LOCK(lock); \ + START_SPIN_LOCK(); \ + } while (false); + + +#define SpinLockRelease(lock) \ + do \ + { \ + S_UNLOCK(lock); \ + END_SPIN_LOCK(); \ + } while (false); -#define SpinLockRelease(lock) S_UNLOCK(lock) #define SpinLockFree(lock) S_LOCK_FREE(lock) -- 2.34.1