CVE-2026-98344

About vulnerability

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

dmaengine: Fix device kref underflow in dma_chan_put()

dma_chan_get() takes chan->device->ref only on the slow path:

/* no kref on fast path */ if (chan->client_count) { __module_get(owner); chan->client_count++; return 0; } if (!try_module_get(owner)) return -ENODEV; if (!dma_device_get(chan->device)) { // calls kref_get_unless_zero()

dma_chan_put() drops the ref unconditionally, so every fast-path get/put pair drops one extra device reference.

The bug fires when two conditions hold together: a non-private provider has a persistent client holding chan->client_count > 0 and another client cycles dmaengine_get()/dmaengine_put(). When the kref hits zero, the subsequent dma_find_channel() returns NULL even though the provider module is still loaded.

Fix this by dropping device->ref only on the last put, matching the single slow-path get.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 11 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU

Affected packages:

kernel @ 5.10.0 (+7 more)

Live-patch status from KernelCare for each operating system.