CVE-2022-49783

/// Technical description

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

x86/fpu: Drop fpregs lock before inheriting FPU permissions

Mike Galbraith reported the following against an old fork of preempt-rt

but the same issue also applies to the current preempt-rt tree.

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46

in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: systemd

preempt_count: 1, expected: 0

RCU nest depth: 0, expected: 0

Preemption disabled at:

fpu_clone

CPU: 6 PID: 1 Comm: systemd Tainted: G E (unreleased)

Call Trace:

<TASK>

dump_stack_lvl

? fpu_clone

__might_resched

rt_spin_lock

fpu_clone

? copy_thread

? copy_process

? shmem_alloc_inode

? kmem_cache_alloc

? kernel_clone

? __do_sys_clone

? do_syscall_64

? __x64_sys_rt_sigprocmask

? syscall_exit_to_user_mode

? do_syscall_64

? syscall_exit_to_user_mode

? do_syscall_

/// 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