In the Linux kernel, the following vulnerability has been resolved: refscale: Fix uninitalized use of wait_queue_head_t Running the refscale test occasionally crashes the kernel with the following error: [ 8569.952896] BUG: unable to handle page fault for address: ffffffffffffffe8 [ 8569.952900] #PF: supervisor read access in kernel mode [ 8569.952902] #PF: error_code(0x0000) - not-present page [ 8569.952904] PGD c4b048067 P4D c4b049067 PUD c4b04b067 PMD 0 [ 8569.952910] Oops: 0000 [#1] PREEMPT_RT SMP NOPTI [ 8569.952916] Hardware name: Dell Inc. PowerEdge R750/0WMWCR, BIOS 1.2.4 05/28/2021 [ 8569.952917] RIP: 0010:prepare_to_wait_event+0x101/0x190 : [ 8569.952940] Call Trace: [ 8569.952941] <TASK> [ 8569.952944] ref_scale_reader+0x380/0x4a0 [refscale] [ 8569.952959] kthread+0x10e/0x130 [ 8569.952966] ret_from_fork+0x1f/0x30 [ 8569.952973] </TASK> The likely cause is that init_waitqueue_head() is called after the call to the torture_create_kthread() function that creates the ref_scale_reader kthread. Although this init_waitqueue_head() call will very likely complete before this kthread is created and starts running, it is possible that the calling kthread will be delayed between the calls to torture_create_kthread() and init_waitqueue_head(). In this case, the new kthread will use the waitqueue head before it is properly initialized, which is not good for the kernel's health and well-being. The above crash happened here: static inline void __add_wait_queue(...) { : if (!(wq->flags & WQ_FLAG_PRIORITY)) <=== Crash here The offset of flags from list_head entry in wait_queue_entry is -0x18. If reader_tasks[i].wq.head.next is NULL as allocated reader_task structure is zero initialized, the instruction will try to access address 0xffffffffffffffe8, which is exactly the fault address listed above. This commit therefore invokes init_waitqueue_head() before creating the kthread.
History

Tue, 30 Dec 2025 12:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: refscale: Fix uninitalized use of wait_queue_head_t Running the refscale test occasionally crashes the kernel with the following error: [ 8569.952896] BUG: unable to handle page fault for address: ffffffffffffffe8 [ 8569.952900] #PF: supervisor read access in kernel mode [ 8569.952902] #PF: error_code(0x0000) - not-present page [ 8569.952904] PGD c4b048067 P4D c4b049067 PUD c4b04b067 PMD 0 [ 8569.952910] Oops: 0000 [#1] PREEMPT_RT SMP NOPTI [ 8569.952916] Hardware name: Dell Inc. PowerEdge R750/0WMWCR, BIOS 1.2.4 05/28/2021 [ 8569.952917] RIP: 0010:prepare_to_wait_event+0x101/0x190 : [ 8569.952940] Call Trace: [ 8569.952941] <TASK> [ 8569.952944] ref_scale_reader+0x380/0x4a0 [refscale] [ 8569.952959] kthread+0x10e/0x130 [ 8569.952966] ret_from_fork+0x1f/0x30 [ 8569.952973] </TASK> The likely cause is that init_waitqueue_head() is called after the call to the torture_create_kthread() function that creates the ref_scale_reader kthread. Although this init_waitqueue_head() call will very likely complete before this kthread is created and starts running, it is possible that the calling kthread will be delayed between the calls to torture_create_kthread() and init_waitqueue_head(). In this case, the new kthread will use the waitqueue head before it is properly initialized, which is not good for the kernel's health and well-being. The above crash happened here: static inline void __add_wait_queue(...) { : if (!(wq->flags & WQ_FLAG_PRIORITY)) <=== Crash here The offset of flags from list_head entry in wait_queue_entry is -0x18. If reader_tasks[i].wq.head.next is NULL as allocated reader_task structure is zero initialized, the instruction will try to access address 0xffffffffffffffe8, which is exactly the fault address listed above. This commit therefore invokes init_waitqueue_head() before creating the kthread.
Title refscale: Fix uninitalized use of wait_queue_head_t
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-30T12:23:46.526Z

Reserved: 2025-12-30T12:06:44.531Z

Link: CVE-2023-54316

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-12-30T13:16:20.867

Modified: 2025-12-30T13:16:20.867

Link: CVE-2023-54316

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.