Hi,

This has been in my notes for a while. MemoryContextAllocAligned() calls 
MemoryContextAllocExtended() and passes “flags" with only MCXT_ALLOC_ZERO 
removed. When “flags" includes MCXT_ALLOC_NO_OOM, MemoryContextAllocExtended() 
may return NULL, but MemoryContextAllocAligned() doesn't handle the returned 
NULL, which may
lead to a crash.

AlignedAllocRealloc() wraps MemoryContextAllocAligned() and handles a NULL 
return from it, which I think further supports that this is a bug.

I didn't find an in-tree call site that passes MCXT_ALLOC_NO_OOM to 
MemoryContextAllocAligned() or palloc_aligned(), so this cannot be triggered 
from current core code. However, a third-party extension could hit the bug.

The attached patch is a quick fix that adds a NULL check.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/




Attachment: v1-0001-Fix-NO_OOM-handling-in-MemoryContextAllocAligned.patch
Description: Binary data

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