CVSS 5.5 · Medium EPSS 0,22%
Kerentanan pada linux kernel. Skor CVSS 3.1 5.5 (Medium) menurut NVD.
In the Linux kernel, the following vulnerability has been resolved: powerpc/smp: do not decrement idle task preempt count in CPU offline With PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we get: BUG: scheduling while atomic: swapper/1/0/0x00000000 no locks held by swapper/1/0. CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100 Call Trace: dump_stack_lvl+0xac/0x108 __schedule_bug+0xac/0xe0 __schedule+0xcf8/0x10d0 schedule_idle+0x3c/0x70 do_idle+0x2d8/0x4a0 cpu_startup_entry+0x38/0x40 start_secondary+0x2ec/0x3a0 start_secondary_prolog+0x10/0x14 This is because powerpc's arch_cpu_idle_dead() decrements the idle task's preempt count, for reasons explained in commit a7c2bb8279d2 ("powerpc: Re-enable preemption before cpu_die()"), specifically "start_secondary() expects a preempt_count() of 0." However, since commit 2c669ef6979c ("powerpc/preempt: Don't touch the idle task's preempt_count during hotplug") and commit f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled"), that justification no longer holds. The idle task isn't supposed to re-enable preemption, so remove the vestigial preempt_enable() from the CPU offline path. Tested with pseries and powernv in qemu, and pseries on PowerVM.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 5.10.50 hingga sebelum 5.10.76 |
| linux | linux kernel | Versi 5.12.17 hingga sebelum 5.13 |
| linux | linux kernel | Versi 5.13.2 hingga sebelum 5.14.15 |
| linux | linux kernel | Versi 5.15 rc1 |
| linux | linux kernel | Versi 5.15 rc2 |
| linux | linux kernel | Versi 5.15 rc3 |
| linux | linux kernel | Versi 5.15 rc4 |
| linux | linux kernel | Versi 5.15 rc5 |
| linux | linux kernel | Versi 5.15 rc6 |