Description (CNA)
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 (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 036b527f92570206da4b8c40b38f8d689e29d0f3; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 5fb1797a8c9485e40e5492fa0338ab5c7d1f3fef; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 57f7f1c6827be7d8f80feca48d2125fb91c6f6ed; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 7c3f4ce651d43705f9ec7f778f642a90d5ff4fba; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before de2677e57d3161390d8a508f08cddec6ef7e4b23; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 1a0d9b406febf23054ad595fd47b29325e70fb2d; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 77906ac448d2fa81fa710ae26c0e591ebdc81154; affected 8ad342a863590b24ce77681b7e081363fb3333f7 before 44dab659064eb5c10adb0306510eebe848ed592d |
| Linux / Linux | affected 5.6; unaffected 0 before 5.6; unaffected 5.10.271 through 5.10.*; unaffected 5.15.222 through 5.15.*; unaffected 6.1.189 through 6.1.*; unaffected 6.6.158 through 6.6.*; unaffected 6.12.112 through 6.12.*; unaffected 6.18.54 through 6.18.*; unaffected 7.2.8 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/036b527f92570206da4b8c40b38f8d689e29d0f3
- https://git.kernel.org/stable/c/5fb1797a8c9485e40e5492fa0338ab5c7d1f3fef
- https://git.kernel.org/stable/c/57f7f1c6827be7d8f80feca48d2125fb91c6f6ed
- https://git.kernel.org/stable/c/7c3f4ce651d43705f9ec7f778f642a90d5ff4fba
- https://git.kernel.org/stable/c/de2677e57d3161390d8a508f08cddec6ef7e4b23
- https://git.kernel.org/stable/c/1a0d9b406febf23054ad595fd47b29325e70fb2d
- https://git.kernel.org/stable/c/77906ac448d2fa81fa710ae26c0e591ebdc81154
- https://git.kernel.org/stable/c/44dab659064eb5c10adb0306510eebe848ed592d