CVE-2026-80626

powerpc/perf: fix preempt count underflow in fsl_emb_pmu_del

State: Published
Severity: Not scored
Published: Aug 28, 2026
Updated: Aug 28, 2026
Reserved: Aug 26, 2026

Description

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	a11106544f33c104706ae42d27219a409b67478e to before c0c7722308c5f303117d8bd555290fdf26b098daAffected a11106544f33c104706ae42d27219a409b67478e to before 67aeb1eb93d4ffd898a3e74a7f3fe46ee71feb28Affected a11106544f33c104706ae42d27219a409b67478e to before 9a515e00b00132b6fc3f1dd62dc5204bbda8cb10Affected a11106544f33c104706ae42d27219a409b67478e to before 5397142d60aa29dcf636f5459d960bfc4f97c42aAffected a11106544f33c104706ae42d27219a409b67478e to before b89477077c834d94381c7bf07d81193bebefcff9Affected a11106544f33c104706ae42d27219a409b67478e to before 73711688479df333acc134e3730fff1acba1843eAffected a11106544f33c104706ae42d27219a409b67478e to before b504fd953664c3f4d176ae8cb594adb3fda9d577Affected a11106544f33c104706ae42d27219a409b67478e to before 81e3a86030462824a67d697739cf3f387f4ba350Affected
LinuxLinux	2.6.34Affected before 2.6.34Not affected 5.10.261 through 5.10.Not affected 5.15.212 through 5.15.Not affected 6.1.178 through 6.1.Not affected 6.6.145 through 6.6.Not affected 6.12.97 through 6.12.Not affected 6.18.40 through 6.18.Not affected 7.1.5 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

a11106544f33c104706ae42d27219a409b67478e to before c0c7722308c5f303117d8bd555290fdf26b098daAffected
a11106544f33c104706ae42d27219a409b67478e to before 67aeb1eb93d4ffd898a3e74a7f3fe46ee71feb28Affected
a11106544f33c104706ae42d27219a409b67478e to before 9a515e00b00132b6fc3f1dd62dc5204bbda8cb10Affected
a11106544f33c104706ae42d27219a409b67478e to before 5397142d60aa29dcf636f5459d960bfc4f97c42aAffected
a11106544f33c104706ae42d27219a409b67478e to before b89477077c834d94381c7bf07d81193bebefcff9Affected
a11106544f33c104706ae42d27219a409b67478e to before 73711688479df333acc134e3730fff1acba1843eAffected
a11106544f33c104706ae42d27219a409b67478e to before b504fd953664c3f4d176ae8cb594adb3fda9d577Affected
a11106544f33c104706ae42d27219a409b67478e to before 81e3a86030462824a67d697739cf3f387f4ba350Affected

LinuxLinux

2.6.34Affected
before 2.6.34Not affected
5.10.261 through 5.10.*Not affected
5.15.212 through 5.15.*Not affected
6.1.178 through 6.1.*Not affected
6.6.145 through 6.6.*Not affected
6.12.97 through 6.12.*Not affected
6.18.40 through 6.18.*Not affected
7.1.5 through 7.1.*Not affected
7.2 and laterNot affected

References

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