CVE-2026-98344 in Linux
요약
\~에 의해 MITRE • 2026. 10. 06.
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.
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