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CVE-2026-98342

dmaengine: wait for RCU readers before releasing dma_device

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: wait for RCU readers before releasing dma_device dma_issue_pending_all() walks the dma_device_list with list_for_each_entry_rcu() under rcu_read_lock(). dma_device_release() unlinks the device with list_del_rcu() and then calls device->device_release() (which in many drivers, such as plx_dma.c, directly calls kfree()). Because there is no grace period between unlinking the device and freeing it, concurrent RCU readers in dma_issue_pending_all() can access the device after it has been freed. The lockless walk originally relied on clients holding a dmaengine reference to pin the provider module, and therefore the device, for as long as they might traverse the list. Commit 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") decoupled the dma_device lifetime from the module reference, so the device can now be released while a reader is still walking the list. Add synchronize_rcu() before the device is freed, so RCU readers are guaranteed to have finished. Keep it unconditional: providers that do not implement device_release() free the device themselves once dma_async_device_unregister() returns. This call will delay for a grace period with dma_list_mutex held, which is safe and only teardown path is delayed.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in ac8ce9f89638d6d79875cca7d8ae42566a9bde15; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in 14578c78405d51fa92e4ada4502a45f537c0fcb8; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in cbb3310a5167e868a5e763e32b9a23b4d50669ee; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in 8577a5ec4f7e00443015ef99f646def093121a1b; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in 4448a539a0c39141cccc67be6cacde0f35024313; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in fc1f4884f1d46fc7a8cee6e2997ecc9e8d1c7f77; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in 4aed7e47a10b94ea3c5171e8d1382081accd2e03; From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 · fixed in dc750422170a563c7a81f6e49d36bb02c62ae37f

  • Linux Linux

    2.6.29

  • KernelLinux

    From 2.6.29 · 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