Record NUMA nodes >= 32 in the partition node bitmap

[rootkiller6788]

Summary

InitNumaTopology (tcmalloc/internal/numa.cc) records each detected NUMA node in the per-partition partition_to_nodes bitmap with:

partition_to_nodes[partition] |= 1 << node;

node is a size_t, but the literal 1 is a 32-bit signed int, so for node >= 31 the shift is undefined behavior. On x86 (and every supported LP64 Linux ABI, where int is 32-bit) the practical result is a corrupted bitmap:

• node == 31: 1 << 31 produces a negative int that sign-extends to 0xffffffff80000000, spuriously setting bits 31..63 of the node bitmap.
• node >= 32: the shift count is masked modulo 32 (e.g. 1 << 32 == 1 << 0), setting a lower node's bit instead of the intended one.

This bitmap is consumed by SystemAllocator::BindMemory (tcmalloc/internal/system_allocator.h) and passed to mbind(2) as the nodemask for NUMA memory binding. On machines with 32 or more NUMA nodes (8-socket EPYC, IBM POWER, etc.) memory can therefore be bound to the wrong nodes — or mbind fails with EINVAL, which is fatal under TCMALLOC_NUMA_AWARE=strict-binding.

Fix

Shift in a 64-bit type so the intended bit is set:

partition_to_nodes[partition] |= uint64_t{1} << node;

Behavior is unchanged for node < 31.

Test

Added NumaTopologyTest.HighNodeIndex, which initializes a topology with 33 synthetic NUMA nodes (node indices 0..32) and asserts that node 32 is recorded in the partition 0 bitmap. Before this change the test fails: 1 << 32 evaluates to 1 on x86, so bit 32 is never set; after the change it passes.

Verification

• Reproduced the corruption with a standalone C++ simulation on x86: for node in {31, 32, 33, 63}, the old expression set 0xffffffff80000000, 0x1, 0x2, and 0xffffffff80000000 respectively, while the fixed expression sets exactly the intended single bit.
• partition_to_nodes is declared as uint64_t partition_to_nodes_[kNumInternalPartitions] in numa.h; uint64_t{1} matches the shift style already used elsewhere in the tree (e.g. tcmalloc/internal/pageflags.cc).