russell@unturf.com
54827d6eb7
ppsspp-0004: sceKernelLockMutex/CB and sceKernelLockLwMutex/CB (4 sites) scan mutex->waitingThreads vector with std::find before push_back -- O(W) per lock attempt. Fix: parallel unordered_set for O(1) dedup. Unit test extended to cover ppsspp-0004; all 8/8 PASS (ratios 5-27x).
37 lines
2.4 KiB
Diff
37 lines
2.4 KiB
Diff
--- a/Core/HLE/sceKernelMutex.cpp
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+++ b/Core/HLE/sceKernelMutex.cpp
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@@ -547,3 +547,3 @@
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// May be in a tight loop timing out (where we don't remove from waitingThreads yet), don't want to add duplicates.
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- if (std::find(mutex->waitingThreads.begin(), mutex->waitingThreads.end(), threadID) == mutex->waitingThreads.end())
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+ if (mutex->waitingThreadSet.insert(threadID).second)
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mutex->waitingThreads.push_back(threadID);
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@@ -569,3 +569,3 @@
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// May be in a tight loop timing out (where we don't remove from waitingThreads yet), don't want to add duplicates.
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- if (std::find(mutex->waitingThreads.begin(), mutex->waitingThreads.end(), threadID) == mutex->waitingThreads.end())
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+ if (mutex->waitingThreadSet.insert(threadID).second)
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mutex->waitingThreads.push_back(threadID);
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@@ -950,3 +950,3 @@
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// May be in a tight loop timing out (where we don't remove from waitingThreads yet), don't want to add duplicates.
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- if (std::find(mutex->waitingThreads.begin(), mutex->waitingThreads.end(), threadID) == mutex->waitingThreads.end())
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+ if (mutex->waitingThreadSet.insert(threadID).second)
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mutex->waitingThreads.push_back(threadID);
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@@ -985,3 +985,3 @@
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// May be in a tight loop timing out (where we don't remove from waitingThreads yet), don't want to add duplicates.
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- if (std::find(mutex->waitingThreads.begin(), mutex->waitingThreads.end(), threadID) == mutex->waitingThreads.end())
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+ if (mutex->waitingThreadSet.insert(threadID).second)
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mutex->waitingThreads.push_back(threadID);
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#
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# CWE-407: sceKernelLockMutex / sceKernelLockMutexCB /
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# sceKernelLockLwMutex / sceKernelLockLwMutexCB each scan
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# mutex->waitingThreads vector with std::find before push_back —
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# O(W) per lock attempt where W = number of waiting threads.
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# The code comment says "May be in a tight loop timing out" — that
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# tight-loop scenario is exactly where O(W) dedup compounds:
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# T attempts * W waiters = O(T*W) total work per timeout cycle.
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# Fix: maintain parallel unordered_set<SceUID> waitingThreadSet for
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# O(1) dedup; remove from set wherever waitingThreads is cleared/erased.
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# Severity: MEDIUM — mutex lock is a hot HLE synchronization path;
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# games with thread pools or producer-consumer patterns will trigger
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# this on every lock contention timeout cycle.
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# Sites: sceKernelLockMutex (line 548), sceKernelLockMutexCB (line 570),
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# sceKernelLockLwMutex (line 951), sceKernelLockLwMutexCB (line 986).
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