Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
s390/cio: Fix device lifecycle handling in css_alloc_subchannel()
css_alloc_subchannel() calls device_initialize() before setting up
the DMA masks. If dma_set_coherent_mask() or dma_set_mask() fails,
the error path frees the subchannel structure directly, bypassing
the device model reference counting.
Once device_initialize() has been called, the embedded struct device
must be released via put_device(), allowing the release callback to
free the container structure.
Fix the error path by dropping the initial device reference with
put_device() instead of calling kfree() directly.
This ensures correct device lifetime handling and avoids potential use-after-free or double-free issues.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 5.14.0 (+13 more)
In the Linux kernel, the following vulnerability has been resolved:
s390/cio: Fix device lifecycle handling in css_alloc_subchannel()
css_alloc_subchannel() calls device_initialize() before setting up
the DMA masks. If dma_set_coherent_mask() or dma_set_mask() fails,
the error path frees the subchannel structure directly, bypassing
the device model reference counting.
Once device_initialize() has been called, the embedded struct device
must be released via put_device(), allowing the release callback to
free the container structure.
Fix the error path by dropping the initial device reference with
put_device() instead of calling kfree() directly.
This ensures correct device lifetime handling and avoids potential use-after-free or double-free issues.