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Backport #9250 to 4.0 - Fix memory pool corruption after allocation failure in FreeObjects::newBlock() - #9254
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AlexPeshkoff merged 1 commit intoOct 30, 2026
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…allocation failure When newExtent() throws (e.g. std::bad_alloc), the current extent has already been retired with decrUsage() but currentExtent still points to it, so the next call retires it again. Its usage count drops below the number of live blocks and the extent (and the medium hunk holding it) can be reclaimed while still in use, leading to crashes in unlinkBlocks()/SemiDoubleLink::remove(). Allocate the new extent first and retire the old one only after success. Backport of FirebirdSQL#9250.
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Backport of #9250 to
v4.0-release.Same change as in master:
FreeObjects::newBlock()allocates the new extent before retiring the current one, so a failingnewExtent()no longer drops the current extent's usage reference twice. The code differs from master only in style (noconstonsize/size1, existing exception specification kept).No unit test: this branch has no Boost test suite. Verified with the scenario of the test from #9250 built against the
commonlibrary of this branch (Release, Linux x64):