CVE-2024-56585

/// Technical description

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

LoongArch: Fix sleeping in atomic context for PREEMPT_RT

Commit bab1c299f3945ffe79 ("LoongArch: Fix sleeping in atomic context in

setup_tlb_handler()") changes the gfp flag from GFP_KERNEL to GFP_ATOMIC

for alloc_pages_node(). However, for PREEMPT_RT kernels we can still get

a "sleeping in atomic context" error:

[ 0.372259] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48

[ 0.372266] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1

[ 0.372268] preempt_count: 1, expected: 0

[ 0.372270] RCU nest depth: 1, expected: 1

[ 0.372272] 3 locks held by swapper/1/0:

[ 0.372274] #0: 900000000c9f5e60 (&pcp->lock){+.+.}-{3:3}, at: get_page_from_freelist+0x524/0x1c60

[ 0.372294] #1: 90000000087013b8 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x50/0x140

[ 0.372305] #2: 900000047fffd388 (&zone->lock){+.+.}-{3:3}, at: __rmqueue_pcplist+0x30

/// 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