cbcvebase.
CVE-2024-36888
published 2024-05-30

CVE-2024-36888: 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…

PriorityP420medium6.2CVSS 3.1
AVLACLPRNUINSUCNINAH
EPSS
0.24%
14.8th percentile
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.

Affected

11 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.8.11-1 (forky)linux 6.8.11-1 (forky)
linuxlinux
linuxlinux>= 8639ecebc9b1796d7074751a350462f5e1c61cd4 < c57824d4fe07c2131f8c48687cbd5ee2be60c767c57824d4fe07c2131f8c48687cbd5ee2be60c767
linuxlinux>= 8639ecebc9b1796d7074751a350462f5e1c61cd4 < 6d559e70b3eb6623935cbe7f94c1912c1099777b6d559e70b3eb6623935cbe7f94c1912c1099777b
linuxlinux>= 8639ecebc9b1796d7074751a350462f5e1c61cd4 < 57a01eafdcf78f6da34fad9ff075ed5dfdd9f42057a01eafdcf78f6da34fad9ff075ed5dfdd9f420
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.8.11-16.8.11-1
linuxlinux_kernel>= 0 < 6.8.11-16.8.11-1
linuxlinux_kernel>= 0 < 6.8.0-40.406.8.0-40.40
linuxlinux_kernel>= 6.6 < 6.6.316.6.31
linuxlinux_kernel>= 6.7 < 6.8.106.8.10

CVSS provenance

nvdv3.16.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
osv6.5MEDIUM
vendor_ubuntu6.5MEDIUM
vendor_debian6.2LOW
vendor_redhat6.2MEDIUM
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