CVE-2026-23206

In the Linux kernel, the following vulnerability has been resolved:

dpaa2-switch: prevent ZEROSIZEPTR dereference when num_ifs is zero

The driver allocates arrays for ports, FDBs, and filter blocks using kcalloc() with ethsw->swattr.numifs as the element count. When the device reports zero interfaces (either due to hardware configuration or firmware issues), kcalloc(0, ...) returns ZEROSIZEPTR (0x10) instead of NULL.

Later in dpaa2switchprobe(), the NAPI initialization unconditionally accesses ethsw->ports[0]->netdev, which attempts to dereference ZEROSIZEPTR (address 0x10), resulting in a kernel panic.

Add a check to ensure num_ifs is greater than zero after retrieving device attributes. This prevents the zero-sized allocations and subsequent invalid pointer dereference.