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Backport #9250 to 5.0 - Fix memory pool corruption after allocation failure in FreeObjects::newBlock() - #9255
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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. Add a unit test that forces the allocation failure via RLIMIT_AS. Backport of FirebirdSQL#9250.
AlexPeshkoff
merged commit Oct 30, 2026
ce00569
into
FirebirdSQL:v5.0-release
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Backport of #9250 to
v5.0-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).Includes the unit test
CommonSuite/AllocSuite/AllocTests/MediumExtentAllocationFailure(src/common/classes/tests/AllocTest.cpp, Linux only), unchanged from #9250:common_testpasses.