CWE
362
Advisory Published
Updated

CVE-2022-49607: perf/core: Fix data race between perf_event_set_output() and perf_mmap_close()

First published: Wed Feb 26 2025(Updated: )

In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix data race between perf_event_set_output() and perf_mmap_close() Yang Jihing reported a race between perf_event_set_output() and perf_mmap_close(): CPU1 CPU2 perf_mmap_close(e2) if (atomic_dec_and_test(&e2->rb->mmap_count)) // 1 - > 0 detach_rest = true ioctl(e1, IOC_SET_OUTPUT, e2) perf_event_set_output(e1, e2) ... list_for_each_entry_rcu(e, &e2->rb->event_list, rb_entry) ring_buffer_attach(e, NULL); // e1 isn't yet added and // therefore not detached ring_buffer_attach(e1, e2->rb) list_add_rcu(&e1->rb_entry, &e2->rb->event_list) After this; e1 is attached to an unmapped rb and a subsequent perf_mmap() will loop forever more: again: mutex_lock(&e->mmap_mutex); if (event->rb) { ... if (!atomic_inc_not_zero(&e->rb->mmap_count)) { ... mutex_unlock(&e->mmap_mutex); goto again; } } The loop in perf_mmap_close() holds e2->mmap_mutex, while the attach in perf_event_set_output() holds e1->mmap_mutex. As such there is no serialization to avoid this race. Change perf_event_set_output() to take both e1->mmap_mutex and e2->mmap_mutex to alleviate that problem. Additionally, have the loop in perf_mmap() detach the rb directly, this avoids having to wait for the concurrent perf_mmap_close() to get around to doing it to make progress.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
Linux Kernel
Linux Kernel>=3.2.49<3.3
Linux Kernel>=3.4.52<3.5
Linux Kernel>=3.9.8<4.9.325
Linux Kernel>=4.10<4.14.290
Linux Kernel>=4.15<4.19.254
Linux Kernel>=4.20<5.4.208
Linux Kernel>=5.5<5.10.134
Linux Kernel>=5.11<5.15.58
Linux Kernel>=5.16<5.18.15
Linux Kernel=5.19-rc1
Linux Kernel=5.19-rc2
Linux Kernel=5.19-rc3
Linux Kernel=5.19-rc4
Linux Kernel=5.19-rc5
Linux Kernel=5.19-rc6

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Frequently Asked Questions

  • What is the severity of CVE-2022-49607?

    CVE-2022-49607 has a moderate severity rating due to a race condition in the Linux kernel.

  • How do I fix CVE-2022-49607?

    To fix CVE-2022-49607, update your Linux kernel to a version that includes the patch for this vulnerability.

  • Which versions of the Linux kernel are affected by CVE-2022-49607?

    CVE-2022-49607 affects multiple versions of the Linux kernel from 3.2.49 up to certain later versions.

  • What are the potential risks of CVE-2022-49607?

    The risks of CVE-2022-49607 include potential system instability and denial of service due to race conditions.

  • Who reported the CVE-2022-49607 vulnerability?

    CVE-2022-49607 was reported by Yang Jihing.

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