In the Linux kernel, the following vulnerability has been resolved: bpf, cpumap: Handle skb as well when clean up ptrring The following warning was reported when running xdpredirectcpu with both skb-mode and stress-mode enabled: ------------[ cut here ]------------ Incorrect XDP memory type (-2128176192) usage WARNING: CPU: 7 PID: 1442 at net/core/xdp.c:405 Modules linked in: CPU: 7 PID: 1442 Comm: kworker/7:0 Tainted: G 6.5.0-rc2+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: events cpumapentryfree RIP: 0010:xdpreturn+0x1e4/0x4a0 ...... Call Trace: <TASK> ? showregs+0x65/0x70 ? _warn+0xa5/0x240 ? _xdpreturn+0x1e4/0x4a0 ...... xdpreturnframe+0x4d/0x150 _cpumapentryfree+0xf9/0x230 processonework+0x6b0/0xb80 workerthread+0x96/0x720 kthread+0x1a5/0x1f0 retfromfork+0x3a/0x70 retfromforkasm+0x1b/0x30 </TASK> The reason for the warning is twofold. One is due to the kthread cpumapkthreadrun() is stopped prematurely. Another one is _cpumapringcleanup() doesn't handle skb mode and treats skbs in ptrring as XDP frames. Prematurely-stopped kthread will be fixed by the preceding patch and ptrring will be empty when _cpumapringcleanup() is called. But as the comments in _cpumapringcleanup() said, handling and freeing skbs in ptr_ring as well to "catch any broken behaviour gracefully".