CVE-2024-26894

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

ACPI: processor_idle: Fix memory leak in acpi_processor_power_exit()

After unregistering the CPU idle device, the memory associated with it is not freed, leading to a memory leak:

unreferenced object 0xffff896282f6c000 (size 1024): comm "swapper/0", pid 1, jiffies 4294893170 hex dump (first 32 bytes): 00 00 00 00 0b 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 8836a742): [<ffffffff993495ed>] kmalloc_trace+0x29d/0x340 [<ffffffff9972f3b3>] acpi_processor_power_init+0xf3/0x1c0 [<ffffffff9972d263>] __acpi_processor_start+0xd3/0xf0 [<ffffffff9972d2bc>] acpi_processor_start+0x2c/0x50 [<ffffffff99805872>] really_probe+0xe2/0x480 [<ffffffff99805c98>] __driver_probe_device+0x78/0x160 [<ffffffff99805daf>] driver_probe_device+0x1f/0x90 [<ffffffff9980601e>] __driver_attach+0xce/0x1c0 [<ffffffff99803170>] bus_for_each_dev+0x70/0xc0 [<ffffffff99804822>] bus_add_driver+0x112/0x210 [<ffffffff99807245>] driver_register+0x55/0x100 [<ffffffff9aee4acb>] acpi_processor_driver_init+0x3b/0xc0 [<ffffffff990012d1>] do_one_initcall+0x41/0x300 [<ffffffff9ae7c4b0>] kernel_init_freeable+0x320/0x470 [<ffffffff99b231f6>] kernel_init+0x16/0x1b0 [<ffffffff99042e6d>] ret_from_fork+0x2d/0x50

Fix this by freeing the CPU idle device after unregistering it.