CVE-2026-80626
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.
How to fix
- Linux Linuxc0c7722308c5f303117d8bd555290fdf26b098da, 67aeb1eb93d4ffd898a3e74a7f3fe46ee71feb28, 9a515e00b00132b6fc3f1dd62dc5204bbda8cb10, 5397142d60aa29dcf636f5459d960bfc4f97c42a, b89477077c834d94381c7bf07d81193bebefcff9, 73711688479df333acc134e3730fff1acba1843e, b504fd953664c3f4d176ae8cb594adb3fda9d577, 81e3a86030462824a67d697739cf3f387f4ba350 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | a11106544f33c104706ae42d27219a409b67478e ≤ v < c0c7722308c5f303117d8bd555290fdf26b098da, a11106544f33c104706ae42d27219a409b67478e ≤ v < 67aeb1eb93d4ffd898a3e74a7f3fe46ee71feb28, a11106544f33c104706ae42d27219a409b67478e ≤ v < 9a515e00b00132b6fc3f1dd62dc5204bbda8cb10, a11106544f33c104706ae42d27219a409b67478e ≤ v < 5397142d60aa29dcf636f5459d960bfc4f97c42a, a11106544f33c104706ae42d27219a409b67478e ≤ v < b89477077c834d94381c7bf07d81193bebefcff9, a11106544f33c104706ae42d27219a409b67478e ≤ v < 73711688479df333acc134e3730fff1acba1843e, a11106544f33c104706ae42d27219a409b67478e ≤ v < b504fd953664c3f4d176ae8cb594adb3fda9d577, a11106544f33c104706ae42d27219a409b67478e ≤ v < 81e3a86030462824a67d697739cf3f387f4ba350, 2.6.34 | c0c7722308c5f303117d8bd555290fdf26b098da, 67aeb1eb93d4ffd898a3e74a7f3fe46ee71feb28, 9a515e00b00132b6fc3f1dd62dc5204bbda8cb10, 5397142d60aa29dcf636f5459d960bfc4f97c42a, b89477077c834d94381c7bf07d81193bebefcff9, 73711688479df333acc134e3730fff1acba1843e, b504fd953664c3f4d176ae8cb594adb3fda9d577, 81e3a86030462824a67d697739cf3f387f4ba350 |
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