Vulnerability record · CVE-2025-39923 · published 1 October 2025
CVE-2025-39923: Linux kernel vulnerability
Linux · Linux Kernel
In the Linux kernel, the following vulnerability has been resolved: dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees When we don't have a clock specified in the device tree, we have no way to ensure the BAM is on. This is often the case for remotely-controlled or remotely-powered BAM instances. In this case, we need to read num-channels from the DT to have all the necessary information to complete probing. However, at the moment invalid device trees without clock and without num-channels still continue probing, because the error handling is missing return statements. The driver will then later try to read the number of channels from the registers. This is unsafe, because it relies on boot firmware and lucky timing to succeed. Unfortunately, the lack of proper error handling here has been abused for several Qualcomm SoCs upstream, causing early boot crashes in several situations [1, 2]. Avoid these early crashes by erroring out when any of the required DT properties are missing. Note that this will break some of the existing DTs upstream (mainly BAM instances related to the crypto engine). However, clearly these DTs have never been tested properly, since the error in the kernel log was just ignored. It's safer to disable the crypto engine for these broken DTBs. [1]: https://lore.kernel.org/r/[email protected]/ [2]: https://lore.kernel.org/r/[email protected]/
Description
In the Linux kernel, the following vulnerability has been resolved: dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees When we don't have a clock specified in the device tree, we have no way to ensure the BAM is on. This is often the case for remotely-controlled or remotely-powered BAM instances. In this case, we need to read num-channels from the DT to have all the necessary information to complete probing. However, at the moment invalid device trees without clock and without num-channels still continue probing, because the error handling is missing return statements. The driver will then later try to read the number of channels from the registers. This is unsafe, because it relies on boot firmware and lucky timing to succeed. Unfortunately, the lack of proper error handling here has been abused for several Qualcomm SoCs upstream, causing early boot crashes in several situations [1, 2]. Avoid these early crashes by erroring out when any of the required DT properties are missing. Note that this will break some of the existing DTs upstream (mainly BAM instances related to the crypto engine). However, clearly these DTs have never been tested properly, since the error in the kernel log was just ignored. It's safer to disable the crypto engine for these broken DTBs. [1]: https://lore.kernel.org/r/[email protected]/ [2]: https://lore.kernel.org/r/[email protected]/
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products
2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
Track CVE-2025-39923 inside VULONE
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2025-39923), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
