diff options
Diffstat (limited to 'src/backend/storage/buffer/bufmgr.c')
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 9b9303ff650..f1ae6f9f844 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -1639,8 +1639,8 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy) * Assume that we acquired a buffer pin for the purposes of * Valgrind buffer client checks (even in !result case) to * keep things simple. Buffers that are unsafe to access are - * not generally guaranteed to be marked undefined in any - * case. + * not generally guaranteed to be marked undefined or + * non-accessible in any case. */ VALGRIND_MAKE_MEM_DEFINED(BufHdrGetBlock(buf), BLCKSZ); break; @@ -1649,7 +1649,16 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy) } else { - /* If we previously pinned the buffer, it must surely be valid */ + /* + * If we previously pinned the buffer, it must surely be valid. + * + * Note: We deliberately avoid a Valgrind client request here. + * Individual access methods can optionally superimpose buffer page + * client requests on top of our client requests to enforce that + * buffers are only accessed while locked (and pinned). It's possible + * that the buffer page is legitimately non-accessible here. We + * cannot meddle with that. + */ result = true; } @@ -1745,7 +1754,13 @@ UnpinBuffer(BufferDesc *buf, bool fixOwner) uint32 buf_state; uint32 old_buf_state; - /* Mark undefined, now that no pins remain in backend */ + /* + * Mark buffer non-accessible to Valgrind. + * + * Note that the buffer may have already been marked non-accessible + * within access method code that enforces that buffers are only + * accessed while a buffer lock is held. + */ VALGRIND_MAKE_MEM_NOACCESS(BufHdrGetBlock(buf), BLCKSZ); /* I'd better not still hold any locks on the buffer */ |