CVE-2023-52791

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

i2c: core: Run atomic i2c xfer when !preemptible

Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is

disabled. However, non-atomic i2c transfers require preemption (e.g. in

wait_for_completion() while waiting for the DMA).

panic() calls preempt_disable_notrace() before calling

emergency_restart(). Therefore, if an i2c device is used for the

restart, the xfer should be atomic. This avoids warnings like:

[ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0

[ 12.676926] Voluntary context switch within RCU read-side critical section!

...

[ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114

[ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70

...

[ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58

[ 13.001050] machine_restart from panic+0x2a8/0x32c

Use !preemptible() inst

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References