CVE-2026-80626

Summary

In the Linux kernel, the following vulnerability has been resolved:

powerpc/perf: fix preempt count underflow in fsl_emb_pmu_del

fsl_emb_pmu_del() unconditionally calls put_cpu_var(cpu_hw_events) at the 'out:' label, but only calls the matching get_cpu_var() after the 'i < 0' early-return check. When event->hw.idx is negative the function jumps to 'out:' without having taken get_cpu_var(), and the trailing put_cpu_var() then issues an unmatched preempt_enable(), underflowing preempt_count.

On a CONFIG_PREEMPT=y kernel preempt_count would underflow and eventually present as a 'scheduling while atomic' BUG.

Move put_cpu_var() to pair with get_cpu_var() so the percpu access is correctly bracketed and the 'out:' label only handles perf_pmu_enable.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < c0c7722308c5f303117d8bd555290fdf26b098daaffected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < 67aeb1eb93d4ffd898a3e74a7f3fe46ee71feb28affected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < 9a515e00b00132b6fc3f1dd62dc5204bbda8cb10affected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < 5397142d60aa29dcf636f5459d960bfc4f97c42aaffected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < b89477077c834d94381c7bf07d81193bebefcff9affected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < 73711688479df333acc134e3730fff1acba1843eaffected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < b504fd953664c3f4d176ae8cb594adb3fda9d577affected
LinuxLinuxa11106544f33c104706ae42d27219a409b67478e < 81e3a86030462824a67d697739cf3f387f4ba350affected
LinuxLinux2.6.34affected
LinuxLinux0 < 2.6.34unaffected
LinuxLinux5.10.261 <= 5.10.*unaffected
LinuxLinux5.15.212 <= 5.15.*unaffected
LinuxLinux6.1.178 <= 6.1.*unaffected
LinuxLinux6.6.145 <= 6.6.*unaffected
LinuxLinux6.12.97 <= 6.12.*unaffected
LinuxLinux6.18.40 <= 6.18.*unaffected
LinuxLinux7.1.5 <= 7.1.*unaffected
LinuxLinux7.2 <= *unaffected

Weaknesses

References