RFR: 8351334: [ubsan] memoryReserver.cpp:552:60: runtime error: applying non-zero offset 1073741824 to null pointer [v7]

[Afshin Zafari]

On Mon, 20 Oct 2025 07:33:17 GMT, Afshin Zafari <azafari at openjdk.org> wrote:

>> src/hotspot/share/gc/shared/jvmFlagConstraintsGC.cpp line 288:
>> 
>>> 286:   // If an overflow happened in Arguments::set_heap_size(), MaxHeapSize will have too large a value.
>>> 287:   // Check for this by ensuring that MaxHeapSize plus the requested min base address still fit within max_uintx.
>>> 288:   if (value + MaxHeapSize < MaxHeapSize) { // overflow
>> 
>> Sorry I am struggling to see how this check differs in practice to the existing check:
>> 
>> (value > (max_uintx - MaxHeapSize))
>> 
>> Further, the comment before the new check seems to relate to the existing check.
>
> Sorry it's my mistake in reading `max - a < b` as `a - b < b` .

Applied.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26955#discussion_r2477850829