# CVE-2024-47744: linux: In the Linux kernel, the following vulnerability has been resolved: KVM: Use dedicated mutex to protect kvm_usage_co... CVE-2024-47744 is fixed in 26 products on 1 platform, first by DEBIAN-CVE-2024-47744, released October 21, 2024. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2024-47744 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0017 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Oct 21, 2024 ## Description In the Linux kernel, the following vulnerability has been resolved: KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock Use a dedicated mutex to guard kvm_usage_count to fix a potential deadlock on x86 due to a chain of locks and SRCU synchronizations. Translating the below lockdep splat, CPU1 #6 will wait on CPU0 #1, CPU0 #8 will wait on CPU2 #3, and CPU2 #7 will wait on CPU1 #4 (if there's a writer, due to the fairness of r/w semaphores). CPU0 CPU1 CPU2 1 lock(&kvm->slots_lock); 2 lock(&vcpu->mutex); 3 lock(&kvm->srcu); 4 lock(cpu_hotplug_lock); 5 lock(kvm_lock); 6 lock(&kvm->slots_lock); 7 lock(cpu_hotplug_lock); 8 sync(&kvm->srcu); Note, there are likely more potential deadlocks in KVM x86, e.g. the same pattern of taking cpu_hotplug_lock outside of kvm_lock likely exists with __kvmclock_cpufreq_notifier(): cpuhp_cpufreq_online() | -> cpufreq_online() | -> cpufreq_gov_performance_limits() | -> __cpufreq_driver_target() | -> __target_index() | -> cpufreq_freq_transition_begin() | -> cpufreq_notify_transition() | -> ... __kvmclock_cpufreq_notifier() But, actually triggering such deadlocks is beyond rare due to the combination of dependencies and timings involved. E.g. the cpufreq notifier is only used on older CPUs without a constant TSC, mucking with the NX hugepage mitigation while VMs are running is very uncommon, and doing so while also onlining/offlining a CPU (necessary to generate contention on cpu_hotplug_lock) would be even more unusual. The most robust solution to the general cpu_hotplug_lock issue is likely to switch vm_list to be an RCU-protected list, e.g. so that x86's cpufreq notifier doesn't to take kvm_lock. For now, settle for fixing the most blatant deadlock, as switching to an RCU-protected list is a much more involved change, but add a comment in locking.rst to call out that care needs to be taken when walking holding kvm_lock and walking vm_list. ====================================================== WARNING: possible circular locking dependency detected 6.10.0-smp--c257535a0c9d-pip #330 Tainted: G S O ------------------------------------------------------ tee/35048 is trying to acquire lock: ff6a80eced71e0a8 (&kvm->slots_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x179/0x1e0 [kvm] but task is already holding lock: ffffffffc07abb08 (kvm_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x14a/0x1e0 [kvm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (kvm_lock){+.+.}-{3:3}: __mutex_lock+0x6a/0xb40 mutex_lock_nested+0x1f/0x30 kvm_dev_ioctl+0x4fb/0xe50 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #2 (cpu_hotplug_lock){++++}-{0:0}: cpus_read_lock+0x2e/0xb0 static_key_slow_inc+0x16/0x30 kvm_lapic_set_base+0x6a/0x1c0 [kvm] kvm_set_apic_base+0x8f/0xe0 [kvm] kvm_set_msr_common+0x9ae/0xf80 [kvm] vmx_set_msr+0xa54/0xbe0 [kvm_intel] __kvm_set_msr+0xb6/0x1a0 [kvm] kvm_arch_vcpu_ioctl+0xeca/0x10c0 [kvm] kvm_vcpu_ioctl+0x485/0x5b0 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #1 (&kvm->srcu){.+.+}-{0:0}: __synchronize_srcu+0x44/0x1a0 ---truncated--- ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-64kb opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-64kb sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-azure opensuse-leap 15.6 | 6.4.0-150600.8.17.2 | [SUSE-SU-2024:3984-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3984-1.md) | Nov 13, 2024 | | Linux | kernel-azure sles 15.6 | 6.4.0-150600.8.17.2 | [SUSE-SU-2024:3984-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3984-1.md) | Nov 13, 2024 | | Linux | kernel-coco sles 15.6 | 6.4.0-15061.9.coco15sp6.1 | [SUSE-SU-2024:4387-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4387-1.md) | Dec 19, 2024 | | Linux | kernel-coco_debug sles 15.6 | 6.4.0-15061.9.coco15sp6.1 | [SUSE-SU-2024:4387-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4387-1.md) | Dec 19, 2024 | | Linux | kernel-debug opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-default opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-default sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-default-base opensuse-leap 15.6 | 6.4.0-150600.23.30.1.150600.12.12.6 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-default-base sles 15.6 | 6.4.0-150600.23.30.1.150600.12.12.6 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-docs opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-docs sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-kvmsmall opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-livepatch-SLE15-SP6-RT_Update_5 sles 15.6 | 1-150600.1.3.1 | [SUSE-SU-2024:3986-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3986-1.md) | Nov 13, 2024 | | Linux | kernel-livepatch-SLE15-SP6_Update_6 sles 15.6 | 1-150600.13.3.5 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-obs-build opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-obs-build sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-obs-qa opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-rt opensuse-leap 15.6 | 6.4.0-150600.10.17.1 | [SUSE-SU-2024:3986-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3986-1.md) | Nov 13, 2024 | | Linux | kernel-rt_debug opensuse-leap 15.6 | 6.4.0-150600.10.17.1 | [SUSE-SU-2024:3986-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3986-1.md) | Nov 13, 2024 | | Linux | kernel-source opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-source sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-source-azure opensuse-leap 15.6 | 6.4.0-150600.8.17.1 | [SUSE-SU-2024:3984-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3984-1.md) | Nov 13, 2024 | | Linux | kernel-source-azure sles 15.6 | 6.4.0-150600.8.17.1 | [SUSE-SU-2024:3984-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3984-1.md) | Nov 13, 2024 | | Linux | kernel-source-coco sles 15.6 | 6.4.0-15061.9.coco15sp6.1 | [SUSE-SU-2024:4387-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4387-1.md) | Dec 19, 2024 | | Linux | kernel-source-rt opensuse-leap 15.6 | 6.4.0-150600.10.17.1 | [SUSE-SU-2024:3986-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3986-1.md) | Nov 13, 2024 | | Linux | kernel-syms opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-syms sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-syms-azure opensuse-leap 15.6 | 6.4.0-150600.8.17.1 | [SUSE-SU-2024:3984-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3984-1.md) | Nov 13, 2024 | | Linux | kernel-syms-azure sles 15.6 | 6.4.0-150600.8.17.1 | [SUSE-SU-2024:3984-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3984-1.md) | Nov 13, 2024 | | Linux | kernel-syms-coco sles 15.6 | 6.4.0-15061.9.coco15sp6.1 | [SUSE-SU-2024:4387-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4387-1.md) | Dec 19, 2024 | | Linux | kernel-syms-rt opensuse-leap 15.6 | 6.4.0-150600.10.17.1 | [SUSE-SU-2024:3986-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-3986-1.md) | Nov 13, 2024 | | Linux | kernel-zfcpdump opensuse-leap 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | kernel-zfcpdump sles 15.6 | 6.4.0-150600.23.30.1 | [SUSE-SU-2024:4318-1](https://patchblox.com/security/data/fix/linux/suse-su-2024-4318-1.md) | Dec 13, 2024 | | Linux | linux Debian 13.5 (trixie) | 6.11.2-1 | [DEBIAN-CVE-2024-47744](https://patchblox.com/security/data/fix/linux/debian-cve-2024-47744.md) | Oct 21, 2024 | | Linux | linux Debian 14 | 6.11.2-1 | [DEBIAN-CVE-2024-47744](https://patchblox.com/security/data/fix/linux/debian-cve-2024-47744.md) | Oct 21, 2024 | --- Data as of 2026-11-08T00:53:09Z UTC. 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