CVE-2024-36962

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

net: ks8851: Queue RX packets in IRQ handler instead of disabling BHs

Currently the driver uses local_bh_disable()/local_bh_enable() in its

IRQ handler to avoid triggering net_rx_action() softirq on exit from

netif_rx(). The net_rx_action() could trigger this driver .start_xmit

callback, which is protected by the same lock as the IRQ handler, so

calling the .start_xmit from netif_rx() from the IRQ handler critical

section protected by the lock could lead to an attempt to claim the

already claimed lock, and a hang.

The local_bh_disable()/local_bh_enable() approach works only in case

the IRQ handler is protected by a spinlock, but does not work if the

IRQ handler is protected by mutex, i.e. this works for KS8851 with

Parallel bus interface, but not for KS8851 with SPI bus interface.

Remove the BH manipulation and instead of calling netif_rx() inside

the IRQ handler code protected by the lock, queue all the received

SKBs in the IRQ handler into a queue first, and once the IRQ handler

exits the critical section protected by the lock, dequeue all the

queued SKBs and push them all into netif_rx(). At this point, it is

safe to trigger the net_rx_action() softirq, since the netif_rx()

call is outside of the lock that protects the IRQ handler.