CVE-2024-50111

What it actually does

Unaligned access exception handler do_ale() may invoke sleeping functions such as get_user() while running in an IRQ-enabled context, violating atomic context rules and triggering kernel warnings about sleeping in invalid context.

Why it matters to the business

Linux systems on affected architectures can experience kernel warnings, potential instability, or degraded reliability when user-mode code triggers unaligned memory accesses during module loads or similar operations.

How an attack unfolds

An attacker with local access crafts or runs code that triggers unaligned memory access from an IRQ-enabled context such as user mode; the exception handler then calls into code paths that attempt to sleep while interrupts are disabled, surfacing the bug.

How to fix it

Update the Linux kernel to a version containing the fix that enables IRQs when do_ale() is entered from an IRQ-enabled context; apply the upstream commit resolving the sleeping-function-in-atomic-context issue.

How to confirm the fix worked

Confirm the kernel version includes the LoongArch access-helper fix; attempt to reproduce unaligned access from user mode and verify absence of the sleeping-function warning and stack trace.

Typical attack path

1. Obtain local execution on a LoongArch Linux system
2. Execute or trigger code performing unaligned memory access from user mode or other IRQ-enabled context
3. Force the kernel into the do_ale() path that calls get_user() without enabling IRQs first
4. Observe resulting kernel warning or context violation

How to detect it

Search kernel logs for the strings 'sleeping function called from invalid context', 'do_ale', 'emulate_load_store_insn', and the associated BUG/WARN stack traces involving handle_ale.

What your security team should do

• Prioritize kernel updates on all LoongArch systems
• Monitor for the specific sleeping-function warning in kernel logs
• Restrict unprivileged local access where feasible until patched