CVE-2026-98881

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

net: bridge: remove stale rcu barrier() in br multicast dev del()

This rcu barrier() came from a time call rcu() calls were used in net/bridge/br multicast.c.

Now kfree rcu() is there, we can remove this problematic rcu barrier() which causes extreme RTNL pressure in many syzbot reports.

INFO: task syz-executor:77945 is blocked on a mutex likely owned by task kworker/u1024:5:36537. task:kworker/u1024:5 state:D stack:24616 pid:36537 tgid:36537 ppid:2 task flags:0x4208060 flags:0x00080000 last sleep:612797637337 Workqueue: netns cleanup net Call Trace: [] context switch+0xf2a/0x1730 kernel/sched/core.c:6483 [] schedule+0x1133/0x43a0 kernel/sched/core.c:8411 [] schedule loop kernel/sched/core.c:8514 [inline] [] schedule+0xab/0x260 kernel/sched/core.c:8529 [] schedule timeout+0xc3/0x2b0 kernel/time/sleep timeout.c:75 [] do wait for common kernel/sched/completion.c:100 [inline] [] wait for common kernel/sched/completion.c:121 [inline] [] wait for common kernel/sched/completion.c:132 [inline] [] wait for completion+0x2c7/0x5d0 kernel/sched/completion.c:153 [] rcu barrier+0x49f/0x620 kernel/rcu/tree.c:3888 [] br multicast dev del+0x303/0x350 net/bridge/br multicast.c:4459 [] br dev uninit+0x1c/0x40 net/bridge/br device.c:157 [] unregister netdevice many notify+0x1c1c/0x2300 net/core/dev.c:12599 [] ops exit rtnl list net/core/net namespace.c:187 [inline] [] ops undo list+0x3d3/0x940 net/core/net namespace.c:248