Description
In the Linux kernel, the following vulnerability has been resolved: serial: msm: Disable DMA for kernel console UART At the moment, concurrent writes from userspace and the kernel to the console can trigger a race condition that results in an infinite loop of the same messages printed over and over again. This is most likely to happen during system startup or shutdown when the init system starts/stops a large number of system services that interact with various kernel code. When userspace writes to the TTY device, the driver initiates an asynchronous DMA transfer and releases the port lock. At the same moment, the kernel printk path might grab the port lock and re-configure the UART controller for PIO, without waiting for the DMA operation to complete. It seems like this collision results in zero progress being reported for the DMA engine, so the same text is printed to the console over and over again. For the kernel console, we want a reliable output path that will be functional even during crashes etc. So rather than implementing complex code to synchronize the kernel console write routines with the userspace DMA write routines, simply disable DMA for the console UART instance. Similar checks exist in many other serial drivers, e.g. 8250_port.c, imx.c, sh-sci.c etc.
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
3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < f58e568dc308c8e13f7730c8de2da5ed514e540daffected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < bb4296de5b538b575978c588cb3738ab8524d01aaffected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < 6acea62738ed4cae6746483026706a773b44dad7affected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < abc1926c88c189e5d698b91ed6890e09ab5c321daffected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < 2727744ccb5ca59090451451ee94f530b1be04a5affected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < d354716245192de2d203f2b35f22ab8dc13595e2affected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < e3b42e326f4f30efcdc90bad5f5ba37e1cd91a47affected3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 to < 22dd2777e6c180e1c945b00f6d18550979436324affected
Linux Linux
Default version status: affected
4.4affected0 to < 4.4unaffected5.10.261 to ≤ 5.10.*unaffected5.15.212 to ≤ 5.15.*unaffected6.1.178 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.97 to ≤ 6.12.*unaffected6.18.40 to ≤ 6.18.*unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/f58e568dc308c8e13f7730c8de2da5ed514e540d ↗
- https://git.kernel.org/stable/c/bb4296de5b538b575978c588cb3738ab8524d01a ↗
- https://git.kernel.org/stable/c/6acea62738ed4cae6746483026706a773b44dad7 ↗
- https://git.kernel.org/stable/c/abc1926c88c189e5d698b91ed6890e09ab5c321d ↗
- https://git.kernel.org/stable/c/2727744ccb5ca59090451451ee94f530b1be04a5 ↗
- https://git.kernel.org/stable/c/d354716245192de2d203f2b35f22ab8dc13595e2 ↗
- https://git.kernel.org/stable/c/e3b42e326f4f30efcdc90bad5f5ba37e1cd91a47 ↗
- https://git.kernel.org/stable/c/22dd2777e6c180e1c945b00f6d18550979436324 ↗