Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
net: mana: fix use-after-free in mana_hwc_destroy_channel() by reordering teardown
A potential race condition exists in mana_hwc_destroy_channel() where hwc->caller_ctx is freed before the HWC’s Completion Queue (CQ) and Event Queue (EQ) are destroyed. This allows an in-flight CQ interrupt handler to dereference freed memory, leading to a use-after-free or NULL pointer dereference in mana_hwc_handle_resp().
mana_smc_teardown_hwc() signals the hardware to stop but does not synchronize against IRQ handlers already executing on other CPUs. The IRQ synchronization only happens in mana_hwc_destroy_cq() via mana_gd_destroy_eq() -> mana_gd_deregister_irq(). Since this runs after kfree(hwc->caller_ctx), a concurrent mana_hwc_rx_event_handler() can dereference freed caller_ctx (and rxq->msg_buf) in mana_hwc_handle_resp().
Fix this by reordering teardown to reverse-of-creation order: destroy the TX/RX work queues and CQ/EQ before freeing hwc->caller_ctx. This ensures all in-flight interrupt handlers complete before the memory they access is freed.
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.4.0 (+3 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 9.6 ESU | Released |
9 kernels
|
| Debian 12 | Released |
35 kernels
|
| Debian 13 | Planned | — |
| Ubuntu 22.04 | Planned | — |
| Ubuntu 24.04 | Planned | — |