CVE-2025-40064 affecting package kernel for versions less than 6.6.157.1-1

In the Linux kernel, the following vulnerability has been resolved: smc: Fix use-after-free in __pnet_find_base_ndev(). syzbot reported use-after-free of net_device in __pnet_find_base_ndev(), which was called during connect(). [0] smc_pnet_find_ism_resource() fetches sk_dst_get(sk)->dev and passes down to pnet_find_base_ndev(), where RTNL is held. Then, UAF happened at __pnet_find_base_ndev() when the dev is first used. This means dev had already been freed before acquiring RTNL in pnet_find_base_ndev(). While dev is going away, dst->dev could be swapped with blackhole_netdev, and the dev's refcnt by dst will be released. We must hold dev's refcnt before calling smc_pnet_find_ism_resource(). Also, smc_pnet_find_roce_resource() has the same problem. Let's use __sk_dst_get() and dst_dev_rcu() in the two functions. [0]: BUG: KASAN: use-after-free in __pnet_find_base_ndev+0x1b1/0x1c0 net/smc/smc_pnet.c:926 Read of size 1 at addr ffff888036bac33a by task syz.0.3632/18609 CPU: 1 UID: 0 PID: 18609 Comm: syz.0.3632 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 __pnet_find_base_ndev+0x1b1/0x1c0 net/smc/smc_pnet.c:926 pnet_find_base_ndev net/smc/smc_pnet.c:946 [inline] smc_pnet_find_ism_by_pnetid