Ensure RandomMmapHint never returns address 0 under TSan builds. - #609
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In ThreadSanitizer builds, RandomMmapHint recomputes candidate addresses in a loop bounded by 10 iterations to find an address range reserved for the application. When tag == MemoryTag::kSampled (tag bits 0), producing 0 left addr == 0 when exiting the loop because there was no addr != 0 check inside or after the TSan loop. Wrap the candidate address computation in a do-while loop to guarantee addr != 0 across all iterations, and assert that addr != 0 before returning. PiperOrigin-RevId: 974141730
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Ensure RandomMmapHint never returns address 0 under TSan builds.
In ThreadSanitizer builds, RandomMmapHint recomputes candidate addresses in
a loop bounded by 10 iterations to find an address range reserved for the
application. When tag == MemoryTag::kSampled (tag bits 0), producing 0
left addr == 0 when exiting the loop because there was no addr != 0 check
inside or after the TSan loop.
Wrap the candidate address computation in a do-while loop to guarantee
addr != 0 across all iterations, and assert that addr != 0 before returning.