firmware: arm_sdei: Fix sleep from invalid context BUG
In the Linux kernel, the following vulnerability has been resolved:
firmware: arm_sdei: Fix sleep from invalid context BUG
Running a preempt-rt (v6.2-rc3-rt1) based kernel on an Ampere Altra
triggers:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0
preempt_count: 0, expected: 0
RCU nest depth: 0, expected: 0
3 locks held by cpuhp/0/24:
#0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248
#1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248
#2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130
irq event stamp: 36
hardirqs last enabled at (35): [] finish_task_switch+0xb4/0x2b0
hardirqs last disabled at (36): [] cpuhp_thread_fun+0x21c/0x248
softirqs last enabled at (0): [] copy_process+0x63c/0x1ac0
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...]
Hardware name: WIWYNN Mt.Jade Server [...]
Call trace:
dump_backtrace+0x114/0x120
show_stack+0x20/0x70
dump_stack_lvl+0x9c/0xd8
dump_stack+0x18/0x34
__might_resched+0x188/0x228
rt_spin_lock+0x70/0x120
sdei_cpuhp_up+0x3c/0x130
cpuhp_invoke_callback+0x250/0xf08
cpuhp_thread_fun+0x120/0x248
smpboot_thread_fn+0x280/0x320
kthread+0x130/0x140
ret_from_fork+0x10/0x20
sdei_cpuhp_up() is called in the STARTING hotplug section,
which runs with interrupts disabled. Use a CPUHP_AP_ONLINE_DYN entry
instead to execute the cpuhp cb later, with preemption enabled.
SDEI originally got its own cpuhp slot to allow interacting
with perf. It got superseded by pNMI and this early slot is not
relevant anymore. [1]
Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the
calling CPU. It is checked that preemption is disabled for them.
_ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'.
Preemption is enabled in those threads, but their cpumask is limited
to 1 CPU.
Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb
don't trigger them.
Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call
which acts on the calling CPU.
[1]:
https://lore.kernel.org/all/5813b8c5-ae3e-87fd-fccc-94c9cd08816d@arm.com/
CVE 정보
EPSS
EPSS는 취약점이 악용될 가능성을 예측하는 점수 모델입니다.
EPSS 점수
EPSS 모델은 0과 1(0~100%) 사이의 확률 점수를 생성합니다. 점수가 높을수록 취약점이 악용될 가능성이 높습니다.
날짜
EPSS V0
EPSS V1
EPSS V2 (> 2022-02-04)
EPSS V3 (> 2025-03-07)
EPSS V4 (> 2025-03-17)
2025-12-25
–
–
–
–
0.02%
2025-12-30
–
–
–
–
0.03%
2026-01-25
–
–
–
–
0.04%
2026-03-08
–
–
–
–
0.04%
2026-04-26
–
–
–
–
0.05%
2026-05-10
–
–
–
–
0.05%
2026-05-31
–
–
–
–
0.03%
2026-06-07
–
–
–
–
0.04%
2026-06-14
–
–
–
–
0.04%
EPSS 백분위수
백분위수는 EPSS 점수에 따라 CVE의 순위를 매기는 데 사용됩니다. 예를 들어 EPSS 점수 기준 95번째 백분위수의 CVE는 다른 CVE의 95%보다 악용될 가능성이 높습니다.