WT-2573: free of stack-allocated WT_REF #2682
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The error path in __wt_split_rewrite can free a WT_REF that was allocated on the stack. Allocate the WT_REF instead, rewriting pages in memory isn't a performance path, and it's a simple solution. This change means we have never exercised this error path before. This is an in-memory run which we've recently added to normal stress testing, but I'm concerned about this, it seems unlikely a page-rewrite would fail in normal testing. Also fix a bug found by inspection, we weren't freeing allocated WT_REF structures that didn't also have associated page images, which could lead to memory leaks. There are failure cases where we would have allocated a WT_REF and either not yet attached a page image or, in some cases, there's no page image to attach. I'm calling the underlying __wt_free_ref() function to free the WT_REF structure even when there's no associated page: that looks safe, but regardless, I want to fix that function if this change fails, not expicitly freeing the WT_REF structure in the split code.
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Thanks! LGTM. |
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