CVE-2024-26698 Information
Description
In the Linux kernel the following vulnerability has been resolved:
hv_netvsc: Fix race condition between netvsc_probe and netvsc_remove
In commit ac5047671758 (\hv_netvsc: Disable NAPI before closing the VMBus channel) napi_disable was getting called for all channels including all subchannels without confirming if they are enabled or not.
This caused hv_netvsc getting hung at napi_disable when netvsc_probe() has finished running but nvdev->subchan_work has not started yet. netvsc_subchan_work() -> rndis_set_subchannel() has not created the sub-channels and because of that netvsc_sc_open() is not running. netvsc_remove() calls cancel_work_sync(&nvdev->subchan_work) for which netvsc_subchan_work did not run.
netif_napi_add() sets the bit NAPI_STATE_SCHED because it ensures NAPI cannot be scheduled. Then netvsc_sc_open() -> napi_enable will clear the NAPIF_STATE_SCHED bit so it can be scheduled. napi_disable() does the opposite.
Now during netvsc_device_remove() when napi_disable is called for those subchannels napi_disable gets stuck on infinite msleep.
This fix addresses this problem by ensuring that napi_disable() is not getting called for non-enabled NAPI struct. But netif_napi_del() is still necessary for these non-enabled NAPI struct for cleanup purpose.
Call trace:
[ 654.559417] task:modprobe state:D stack: 0 pid: 2321 ppid: 1091 flags:0x00004002
[ 654.568030] Call Trace:
[ 654.571221]
Reference
https://git.kernel.org/stable/c/9ec807e7b6f5fcf9499f3baa69f254bb239a847f https://git.kernel.org/stable/c/7656372ae190e54e8c8cf1039725a5ea59fdf84a https://git.kernel.org/stable/c/48a8ccccffbae10c91d31fc872db5c31aba07518 https://git.kernel.org/stable/c/22a77c0f5b8233237731df3288d067af51a2fd7b https://git.kernel.org/stable/c/0e8875de9dad12805ff66e92cd5edea6a421f1cd https://git.kernel.org/stable/c/e0526ec5360a48ad3ab2e26e802b0532302a7e11
Share on: