CVE-2024-47696

CVE-2024-47696 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency In the commit aee2424246f9 ("RDMA/iwcm: Fix a use-after-free related to destroying CM IDs"), the function flush_workqueue is invoked to flush the work queue iwcm_wq. But at that time, the work queue iwcm_wq was created via the function alloc_ordered_workqueue without the flag WQ_MEM_RECLAIM. Because the current process is trying to flush the whole iwcm_wq, if iwcm_wq doesn't have the flag WQ_MEM_RECLAIM, verify that the current process is not reclaiming memory or running on a workqueue which doesn't have the flag WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to a deadlock. The call trace is as below: [ 125.350876][ T1430] Call Trace: [ 125.356281][ T1430] <TASK> [ 125.361285][ T1430] ? __warn (kernel/panic.c:693) [ 125.367640][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.375689][ T1430] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 125.382505][ T1430] ? handle_bug (arch/x86/kernel/traps.c:239) [ 125.388987][ T1430] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 125.395831][ T1430] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621) [ 125.403125][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.410984][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.418764][ T1430] __flush_workqueue (kernel/workqueue.c:3970) [ 125.426021][ T1430] ? __pfx___might_resched (kernel/sched/core.c:10151) [ 125.433431][ T1430] ? destroy_cm_id (drivers/infiniband/core/iwcm.c:375) iw_cm [ 125.441209][ T1430] ? __pfx___flush_workqueue (kernel/workqueue.c:3910) [ 125.473900][ T1430] ? _raw_spin_lock_irqsave (arch/x86/include/asm/atomic.h:107 include/linux/atomic/atomic-arch-fallback.h:2170 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:111 kernel/locking/spinlock.c:162) [ 125.473909][ T1430] ? __pfx__raw_spin_lock_irqsave (kernel/locking/spinlock.c:161) [ 125.482537][ T1430] _destroy_id (drivers/infiniband/core/cma.c:2044) rdma_cm [ 125.495072][ T1430] nvme_rdma_free_queue (drivers/nvme/host/rdma.c:656 drivers/nvme/host/rdma.c:650) nvme_rdma [ 125.505827][ T1430] nvme_rdma_reset_ctrl_work (drivers/nvme/host/rdma.c:2180) nvme_rdma [ 125.505831][ T1430] process_one_work (kernel/workqueue.c:3231) [ 125.515122][ T1430] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3393) [ 125.515127][ T1430] ? __pfx_worker_thread (kernel/workqueue.c:3339) [ 125.531837][ T1430] kthread (kernel/kthread.c:389) [ 125.539864][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.550628][ T1430] ret_from_fork (arch/x86/kernel/process.c:147) [ 125.558840][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.558844][ T1430] ret_from_fork_asm (arch/x86/entry/entry_64.S:257) [ 125.566487][ T1430] </TASK> [ 125.566488][ T1430] ---[ end trace 0000000000000000 ]---

Frequently asked questions

What is CVE-2024-47696?
In the Linux kernel, the following vulnerability has been resolved: RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency In the commit aee2424246f9 ("RDMA/iwcm: Fix a use-after-free related to destroying CM IDs"), the function flush_workqueue is invoked to flush the work queue iwcm_wq. But at that time, the work queue iwcm_wq was created via the function alloc_ordered_workqueue without the flag WQ_MEM_RECLAIM. Because the current process is trying to flush the whole iwcm_wq, if iwcm_wq doesn't have the flag WQ_MEM_RECLAIM, verify that the current process is not reclaiming memory or running on a workqueue which doesn't have the flag WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to a deadlock. The call trace is as below: [ 125.350876][ T1430] Call Trace: [ 125.356281][ T1430] <TASK> [ 125.361285][ T1430] ? __warn (kernel/panic.c:693) [ 125.367640][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.375689][ T1430] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 125.382505][ T1430] ? handle_bug (arch/x86/kernel/traps.c:239) [ 125.388987][ T1430] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 125.395831][ T1430] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621) [ 125.403125][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.410984][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.418764][ T1430] __flush_workqueue (kernel/workqueue.c:3970) [ 125.426021][ T1430] ? __pfx___might_resched (kernel/sched/core.c:10151) [ 125.433431][ T1430] ? destroy_cm_id (drivers/infiniband/core/iwcm.c:375) iw_cm [ 125.441209][ T1430] ? __pfx___flush_workqueue (kernel/workqueue.c:3910) [ 125.473900][ T1430] ? _raw_spin_lock_irqsave (arch/x86/include/asm/atomic.h:107 include/linux/atomic/atomic-arch-fallback.h:2170 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:111 kernel/locking/spinlock.c:162) [ 125.473909][ T1430] ? __pfx__raw_spin_lock_irqsave (kernel/locking/spinlock.c:161) [ 125.482537][ T1430] _destroy_id (drivers/infiniband/core/cma.c:2044) rdma_cm [ 125.495072][ T1430] nvme_rdma_free_queue (drivers/nvme/host/rdma.c:656 drivers/nvme/host/rdma.c:650) nvme_rdma [ 125.505827][ T1430] nvme_rdma_reset_ctrl_work (drivers/nvme/host/rdma.c:2180) nvme_rdma [ 125.505831][ T1430] process_one_work (kernel/workqueue.c:3231) [ 125.515122][ T1430] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3393) [ 125.515127][ T1430] ? __pfx_worker_thread (kernel/workqueue.c:3339) [ 125.531837][ T1430] kthread (kernel/kthread.c:389) [ 125.539864][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.550628][ T1430] ret_from_fork (arch/x86/kernel/process.c:147) [ 125.558840][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.558844][ T1430] ret_from_fork_asm (arch/x86/entry/entry_64.S:257) [ 125.566487][ T1430] </TASK> [ 125.566488][ T1430] ---[ end trace 0000000000000000 ]---
How severe is CVE-2024-47696?
CVE-2024-47696 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2024-47696 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-47696?
CVE-2024-47696 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-47696?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2024-47696 have an EU (EUVD) identifier?
Yes. CVE-2024-47696 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-42616.
When was CVE-2024-47696 published?
CVE-2024-47696 was published on 2024-10-21 and last updated on 2026-06-17.

References

Affected products (1)

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