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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2024-57951

hrtimers: Handle CPU state correctly on hotplug

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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 ]

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 54d0d83a53508d687fd4a225f8aa1f18559562d0 to < 95e4f62df23f4df1ce6ef897d44b8e23c260921aaffected
  • 7f4c89400d2997939f6971c7981cc780a219e36b to < 14984139f1f2768883332965db566ef26db609e7affected
  • 6fcbcc6c8e52650749692c7613cbe71bf601670d to < 15b453db41d36184cf0ccc21e7df624014ab6a1aaffected
  • 75b5016ce325f1ef9c63e5398a1064cf8a7a7354 to < 3d41dbf82e10c44e53ea602398ab002baec27e75affected
  • 53f408cad05bb987af860af22f4151e5a18e6ee8 to < a5cbbea145b400e40540c34816d16d36e0374fbcaffected
  • 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 to < 38492f6ee883c7b1d33338bf531a62cff69b4b28affected
  • 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 to < 2f8dea1692eef2b7ba6a256246ed82c365fdc686affected
  • 9a2fc41acb69dd4e2a58d0c04346c3333c2341fcaffected
  • 5.4.264 to < 5.4.290affected
  • 5.10.204 to < 5.10.234affected
  • 5.15.143 to < 5.15.177affected
  • 6.1.68 to < 6.1.127affected
  • 6.6.7 to < 6.6.74affected
  • 4.19.302 to < 4.20affected

Linux Linux

Default version status: affected

  • 6.7affected
  • 0 to < 6.7unaffected
  • 5.4.290 to ≤ 5.4.*unaffected
  • 5.10.234 to ≤ 5.10.*unaffected
  • 5.15.177 to ≤ 5.15.*unaffected
  • 6.1.127 to ≤ 6.1.*unaffected
  • 6.6.74 to ≤ 6.6.*unaffected
  • 6.12.11 to ≤ 6.12.*unaffected
  • 6.13 to ≤ *unaffected

References