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Commit46ef520

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Mark buffers as defined to Valgrind consistently.
Make PinBuffer() mark buffers as defined to Valgrind unconditionally,including when the buffer header spinlock must be acquired. Failure tohandle that case could lead to false positive reports from Valgrind.This theoretically creates a risk that we'll mark buffers defined evenwhen external callers don't end up with a buffer pin. That seemsperfectly acceptable, though, since in general we make no guaranteesabout buffers that are unsafe to access being reliably marked as unsafe.Oversight in commit1e0dfd1, which added valgrind buffer accessinstrumentation.
1 parent72eab84 commit46ef520

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‎src/backend/storage/buffer/bufmgr.c

Lines changed: 6 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1636,11 +1636,13 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy)
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result= (buf_state&BM_VALID)!=0;
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/*
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* If we successfully acquired our first pin on this buffer
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* within this backend, mark buffer contents defined
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* Assume that we acquired a buffer pin for the purposes of
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* Valgrind buffer client checks (even in !result case) to
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* keep things simple. Buffers that are unsafe to access are
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* not generally guaranteed to be marked undefined in any
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* case.
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*/
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if (result)
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VALGRIND_MAKE_MEM_DEFINED(BufHdrGetBlock(buf),BLCKSZ);
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VALGRIND_MAKE_MEM_DEFINED(BufHdrGetBlock(buf),BLCKSZ);
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break;
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}
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}

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