net: mvpp2: prevent buffer overflow in page_pool allocation

The per‑processor buffering scheme is supported only if the
number of pools (nrxqs * 2) does not exceed MVPP2_BM_MAX_POOLS (8).
This is already checked in mvpp2_probe() during the initial
activation of percpu_pools.

However, mvpp2_change_mtu() may later call
mvpp2_bm_switch_buffers(priv, true) without this check, which can
lead to an out-of-bounds access in the priv->page_pool array in
mvpp2_bm_init(). The array is sized to hold MVPP2_PORT_MAX_RXQ
entries, and mvpp2_get_nrxqs() may return exactly that value. The
per-CPU scheme then doubles it to nrxqs * 2, exceeding the array
bounds.

Check that the hardware version is MVPP22 or newer and that the
number of pools (nrxqs * 2) does not exceed MVPP2_BM_MAX_POOLS
before switching to per-CPU mode.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 7d04b0b13b11 ("mvpp2: percpu buffers")
Signed-off-by: Dmitriy Okunev <dokunevdmitriy@gmail.com>
Link: https://patch.msgid.link/20260914091557.71769-1-dokunevdmitriy@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

0 files changed, 0 insertions, 0 deletions