CVE-2026-53008

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

ice: fix race condition in TX timestamp ring cleanup

Fix a race condition between ice_free_tx_tstamp_ring() and ice_tx_map()

that can cause a NULL pointer dereference.

ice_free_tx_tstamp_ring currently clears the ICE_TX_FLAGS_TXTIME flag

after NULLing the tstamp_ring. This could allow a concurrent ice_tx_map

call on another CPU to dereference the tstamp_ring, which could lead to

a NULL pointer dereference.

CPU A:ice_free_tx_tstamp_ring() | CPU B:ice_tx_map()

--------------------------------|---------------------------------

tx_ring->tstamp_ring = NULL |

| ice_is_txtime_cfg() -> true

| tstamp_ring = tx_ring->tstamp_ring

| tstamp_ring->count // NULL deref!

flags &= ~ICE_TX_FLAGS_TXTIME |

Fix by:

1. Reordering ice_free_tx_tstamp_ring() to clear the flag before

NULLing the pointer, with smp_wmb() to ensure proper ordering.

2. Adding smp_rmb() in ice_tx_map() after the flag check to order the

flag read before the pointer read, using READ_ONCE() for the

pointer, and adding a NULL check as a safety net.

3. Converting tx_ring->flags from u8 to DECLARE_BITMAP() and using

atomic bitops (set_bit(), clear_bit(), test_bit()) for all flag

operations throughout the driver:

- ICE_TX_RING_FLAGS_XDP

- ICE_TX_RING_FLAGS_VLAN_L2TAG1

- ICE_TX_RING_FLAGS_VLAN_L2TAG2

- ICE_TX_RING_FLAGS_TXTIME