In the Linux kernel, the following vulnerability has been resolved:
workqueue: Fix selection of wake_cpu in kick_pool()
With cpu_possible_mask=0-63 and cpu_online_mask=0-7 the following
kernel oops was observed:
smp: Bringing up secondary CPUs …
smp: Brought up 1 node, 8 CPUs
Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 0000000000000000 TEID: 0000000000000803
[…]
Call Trace:
arch_vcpu_is_preempted+0x12/0x80
select_idle_sibling+0x42/0x560
select_task_rq_fair+0x29a/0x3b0
try_to_wake_up+0x38e/0x6e0
kick_pool+0xa4/0x198
__queue_work.part.0+0x2bc/0x3a8
call_timer_fn+0x36/0x160
__run_timers+0x1e2/0x328
__run_timer_base+0x5a/0x88
run_timer_softirq+0x40/0x78
__do_softirq+0x118/0x388
irq_exit_rcu+0xc0/0xd8
do_ext_irq+0xae/0x168
ext_int_handler+0xbe/0xf0
psw_idle_exit+0x0/0xc
default_idle_call+0x3c/0x110
do_idle+0xd4/0x158
cpu_startup_entry+0x40/0x48
rest_init+0xc6/0xc8
start_kernel+0x3c4/0x5e0
startup_continue+0x3c/0x50
The crash is caused by calling arch_vcpu_is_preempted() for an offline
CPU. To avoid this, select the cpu with cpumask_any_and_distribute()
to mask __pod_cpumask with cpu_online_mask. In case no cpu is left in
the pool, skip the assignment.
tj: This doesn’t fully fix the bug as CPUs can still go down between
picking
the target CPU and the wake call. Fixing that likely requires adding
cpu_online() test to either the sched or s390 arch code. However,
regardless
of how that is fixed, workqueue shouldn’t be picking a CPU which isn’t
online as that would result in unpredictable and worse behavior.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 18.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 23.10 | noarch | linux | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 14.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 16.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 18.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws | < any | UNKNOWN |
git.kernel.org/linus/57a01eafdcf78f6da34fad9ff075ed5dfdd9f420 (6.9-rc7)
git.kernel.org/stable/c/57a01eafdcf78f6da34fad9ff075ed5dfdd9f420
git.kernel.org/stable/c/6d559e70b3eb6623935cbe7f94c1912c1099777b
git.kernel.org/stable/c/c57824d4fe07c2131f8c48687cbd5ee2be60c767
launchpad.net/bugs/cve/CVE-2024-36888
nvd.nist.gov/vuln/detail/CVE-2024-36888
security-tracker.debian.org/tracker/CVE-2024-36888
www.cve.org/CVERecord?id=CVE-2024-36888