In the Linux kernel, the following vulnerability has been resolved:
ionic: fix use after netif_napi_del()
When queues are started, netif_napi_add() and napi_enable() are called. If there are 4 queues and only 3 queues are used for the current configuration, only 3 queues' napi should be registered and enabled. The ionic_qcq_enable() checks whether the .poll pointer is not NULL for enabling only the using queue' napi. Unused queues' napi will not be registered by netif_napi_add(), so the .poll pointer indicates NULL. But it couldn't distinguish whether the napi was unregistered or not because netif_napi_del() doesn't reset the .poll pointer to NULL. So, ionic_qcq_enable() calls napi_enable() for the queue, which was unregistered by netif_napi_del().
Reproducer: ethtool -L <interface name> rx 1 tx 1 combined 0 ethtool -L <interface name> rx 0 tx 0 combined 1 ethtool -L <interface name> rx 0 tx 0 combined 4
Splat looks like: kernel BUG at net/core/dev.c:6666! Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 3 PID: 1057 Comm: kworker/3:3 Not tainted 6.10.0-rc2+ #16 Workqueue: events ionic_lif_deferred_work [ionic] RIP: 0010:napi_enable+0x3b/0x40 Code: 48 89 c2 48 83 e2 f6 80 b9 61 09 00 00 00 74 0d 48 83 bf 60 01 00 00 00 74 03 80 ce 01 f0 4f RSP: 0018:ffffb6ed83227d48 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff97560cda0828 RCX: 0000000000000029 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff97560cda0a28 RBP: ffffb6ed83227d50 R08: 0000000000000400 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: ffff97560ce3c1a0 R14: 0000000000000000 R15: ffff975613ba0a20 FS: 0000000000000000(0000) GS:ffff975d5f780000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8f734ee200 CR3: 0000000103e50000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <TASK> ? die+0x33/0x90 ? do_trap+0xd9/0x100 ? napi_enable+0x3b/0x40 ? do_error_trap+0x83/0xb0 ? napi_enable+0x3b/0x40 ?...