CVE-2024-57939

/// Technical description

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

riscv: Fix sleeping in invalid context in die()

die() can be called in exception handler, and therefore cannot sleep.

However, die() takes spinlock_t which can sleep with PREEMPT_RT enabled.

That causes the following warning:

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48

in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 285, name: mutex

preempt_count: 110001, expected: 0

RCU nest depth: 0, expected: 0

CPU: 0 UID: 0 PID: 285 Comm: mutex Not tainted 6.12.0-rc7-00022-ge19049cf7d56-dirty #234

Hardware name: riscv-virtio,qemu (DT)

Call Trace:

dump_backtrace+0x1c/0x24

show_stack+0x2c/0x38

dump_stack_lvl+0x5a/0x72

dump_stack+0x14/0x1c

__might_resched+0x130/0x13a

rt_spin_lock+0x2a/0x5c

die+0x24/0x112

do_trap_insn_illegal+0xa0/0xea

_new_vmalloc_restore_context_a0+0xcc/0xd8

Oops - illegal instruction [#1]

Switch to use raw_spinlock_t, which does

/// 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