CVE-2026-98344 is a vulnerability in Linux Kernel
Published on October 6, 2026
dmaengine: Fix device kref underflow in dma_chan_put()
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.
Products Associated with CVE-2026-98344
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Affected Versions
Linux:- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 036b527f92570206da4b8c40b38f8d689e29d0f3 is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 5fb1797a8c9485e40e5492fa0338ab5c7d1f3fef is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 57f7f1c6827be7d8f80feca48d2125fb91c6f6ed is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 7c3f4ce651d43705f9ec7f778f642a90d5ff4fba is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below de2677e57d3161390d8a508f08cddec6ef7e4b23 is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 1a0d9b406febf23054ad595fd47b29325e70fb2d is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 77906ac448d2fa81fa710ae26c0e591ebdc81154 is affected.
- Version 8ad342a863590b24ce77681b7e081363fb3333f7 and below 44dab659064eb5c10adb0306510eebe848ed592d is affected.
- Version 5.6 is affected.
- Before 5.6 is unaffected.
- Version 5.10.271, <= 5.10.* is unaffected.
- Version 5.15.222, <= 5.15.* is unaffected.
- Version 6.1.189, <= 6.1.* is unaffected.
- Version 6.6.158, <= 6.6.* is unaffected.
- Version 6.12.112, <= 6.12.* is unaffected.
- Version 6.18.54, <= 6.18.* is unaffected.
- Version 7.2.8, <= 7.2.* is unaffected.
- Version 7.3-rc4, <= * is unaffected.