Description
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 products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
8ad342a863590b24ce77681b7e081363fb3333f7 to < 036b527f92570206da4b8c40b38f8d689e29d0f3affected8ad342a863590b24ce77681b7e081363fb3333f7 to < 5fb1797a8c9485e40e5492fa0338ab5c7d1f3fefaffected8ad342a863590b24ce77681b7e081363fb3333f7 to < 57f7f1c6827be7d8f80feca48d2125fb91c6f6edaffected8ad342a863590b24ce77681b7e081363fb3333f7 to < 7c3f4ce651d43705f9ec7f778f642a90d5ff4fbaaffected8ad342a863590b24ce77681b7e081363fb3333f7 to < de2677e57d3161390d8a508f08cddec6ef7e4b23affected8ad342a863590b24ce77681b7e081363fb3333f7 to < 1a0d9b406febf23054ad595fd47b29325e70fb2daffected8ad342a863590b24ce77681b7e081363fb3333f7 to < 77906ac448d2fa81fa710ae26c0e591ebdc81154affected8ad342a863590b24ce77681b7e081363fb3333f7 to < 44dab659064eb5c10adb0306510eebe848ed592daffected
Linux Linux
Default version status: affected
5.6affected0 to < 5.6unaffected5.10.271 to ≤ 5.10.*unaffected5.15.222 to ≤ 5.15.*unaffected6.1.189 to ≤ 6.1.*unaffected6.6.158 to ≤ 6.6.*unaffected6.12.112 to ≤ 6.12.*unaffected6.18.54 to ≤ 6.18.*unaffected7.2.8 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
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 ↗