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CVE-2024-57951

hrtimers: Handle CPU state correctly on hotplug

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.4.290, 5.10.234, 5.15.177, 6.1.127, 6.6.74, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

In the Linux kernel, the following vulnerability has been resolved: hrtimers: Handle CPU state correctly on hotplug Consider a scenario where a CPU transitions from CPUHP_ONLINE to halfway through a CPU hotunplug down to CPUHP_HRTIMERS_PREPARE, and then back to CPUHP_ONLINE: Since hrtimers_prepare_cpu() does not run, cpu_base.hres_active remains set to 1 throughout. However, during a CPU unplug operation, the tick and the clockevents are shut down at CPUHP_AP_TICK_DYING. On return to the online state, for instance CFS incorrectly assumes that the hrtick is already active, and the chance of the clockevent device to transition to oneshot mode is also lost forever for the CPU, unless it goes back to a lower state than CPUHP_HRTIMERS_PREPARE once. This round-trip reveals another issue; cpu_base.online is not set to 1 after the transition, which appears as a WARN_ON_ONCE in enqueue_hrtimer(). Aside of that, the bulk of the per CPU state is not reset either, which means there are dangling pointers in the worst case. Address this by adding a corresponding startup() callback, which resets the stale per CPU state and sets the online flag. [ tglx: Make the new callback unconditionally available, remove the online modification in the prepare() callback and clear the remaining state in the starting callback instead of the prepare callback ]

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 54d0d83a53508d687fd4a225f8aa1f18559562d0 · fixed in 95e4f62df23f4df1ce6ef897d44b8e23c260921a; From 7f4c89400d2997939f6971c7981cc780a219e36b · fixed in 14984139f1f2768883332965db566ef26db609e7; From 6fcbcc6c8e52650749692c7613cbe71bf601670d · fixed in 15b453db41d36184cf0ccc21e7df624014ab6a1a; From 75b5016ce325f1ef9c63e5398a1064cf8a7a7354 · fixed in 3d41dbf82e10c44e53ea602398ab002baec27e75; From 53f408cad05bb987af860af22f4151e5a18e6ee8 · fixed in a5cbbea145b400e40540c34816d16d36e0374fbc; From 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 · fixed in 38492f6ee883c7b1d33338bf531a62cff69b4b28; From 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 · fixed in 2f8dea1692eef2b7ba6a256246ed82c365fdc686; From 5.4.264 · fixed in 5.4.290; From 5.10.204 · fixed in 5.10.234; From 5.15.143 · fixed in 5.15.177; From 6.1.68 · fixed in 6.1.127; From 6.6.7 · fixed in 6.6.74; From 4.19.302 · fixed in 4.20

  • Linux Linux

    6.7

  • KernelLinux

    fixed in 5.4.290; From 5.5.0 · fixed in 5.10.234; From 5.11.0 · fixed in 5.15.177; From 5.16.0 · fixed in 6.1.127; From 6.2.0 · fixed in 6.6.74; From 6.7.0 · fixed in 6.12.11

References 7

git.kernel.org