CVE-2026-53008: ice: fix race condition in TX timestamp ring cleanup

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

The Linux kernel CVE team has assigned CVE-2026-53008 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.18 with commit ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 and fixed in 7.0.10 with commit 097409d20465723283632515df73038a4a853eda
	Issue introduced in 6.18 with commit ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 and fixed in 7.1 with commit 7c72ec18c2a4111204c2e915f8e4f6d849ce9398

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-53008
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/intel/ice/ice.h
	drivers/net/ethernet/intel/ice/ice_dcb_lib.c
	drivers/net/ethernet/intel/ice/ice_lib.c
	drivers/net/ethernet/intel/ice/ice_txrx.c
	drivers/net/ethernet/intel/ice/ice_txrx.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/097409d20465723283632515df73038a4a853eda
	https://git.kernel.org/stable/c/7c72ec18c2a4111204c2e915f8e4f6d849ce9398