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CVE-2026-98344

dmaengine: Fix device kref underflow in dma_chan_put()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 036b527f92570206da4b8c40b38f8d689e29d0f3; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 5fb1797a8c9485e40e5492fa0338ab5c7d1f3fef; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 57f7f1c6827be7d8f80feca48d2125fb91c6f6ed; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 7c3f4ce651d43705f9ec7f778f642a90d5ff4fba; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in de2677e57d3161390d8a508f08cddec6ef7e4b23; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 1a0d9b406febf23054ad595fd47b29325e70fb2d; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 77906ac448d2fa81fa710ae26c0e591ebdc81154; From 8ad342a863590b24ce77681b7e081363fb3333f7 · fixed in 44dab659064eb5c10adb0306510eebe848ed592d

  • Linux Linux

    5.6

  • KernelLinux

    From 5.6.0 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.54; From 6.19.0 · fixed in 7.2.8

References 8

git.kernel.org