CVE-2026-68286drop_monitor: perform u64_stats updates under IRQ-disabled section

Official description

In the Linux kernel, the following vulnerability has been resolved: drop_monitor: perform u64_stats updates under IRQ-disabled section In net_dm_packet_trace_kfree_skb_hit() and net_dm_hw_trap_packet_probe(), u64_stats_update_begin() / u64_stats_inc() / u64_stats_update_end() were called after spin_unlock_irqrestore(&...drop_queue.lock, flags), when local IRQs had already been re-enabled. Tracepoint probes can execute in IRQ or softirq context. On 32-bit architectures, u64_stats_update_begin() disables preemption but not interrupts, relying on seqcount writes. If a nested interrupt occurs on the same CPU during the 64-bit stats update, the reentrant seqcount update can corrupt the seqcount state or stats value. Fix this by performing the 64-bit per-CPU stats update before releasing drop_queue.lock via spin_unlock_irqrestore(), ensuring local interrupts remain disabled during the u64_stats update.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/dd8472526a04f2185afd792b8041a912a7d75d85
• https://git.kernel.org/stable/c/3454c729ee8aa682ec871f1b174b047f731933ae
• https://git.kernel.org/stable/c/be9b121894d6ad44f0011f79543a2e3245979497
• https://git.kernel.org/stable/c/7d857cf5f0120bb0e020fa20b03bd21b9d3e0c04
• https://git.kernel.org/stable/c/d5e2cd2bc8ae36617346b3a54ee9da61d866bf92
• https://git.kernel.org/stable/c/fd098a23bf8fda7eae48db9b06e7c34fc4d228fa