From 5819e464a17587e6830cfab05f3e91a9a8753a41 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Thu, 8 Aug 2024 14:08:08 +1000 Subject: [PATCH] cpumask: Fix crash on updating CPU enabled mask The CPU enabled mask instead of the CPU possible mask should be used by set_cpu_enabled(). Otherwise, we run into crash due to write to the read-only CPU possible mask when vCPU is hot added on ARM64. (qemu) device_add host-arm-cpu,id=cpu1,socket-id=1 Unable to handle kernel write to read-only memory at virtual address ffff800080fa7190 : Call trace: register_cpu+0x1a4/0x2e8 arch_register_cpu+0x84/0xd8 acpi_processor_add+0x480/0x5b0 acpi_bus_attach+0x1c4/0x300 acpi_dev_for_one_check+0x3c/0x50 device_for_each_child+0x68/0xc8 acpi_dev_for_each_child+0x48/0x80 acpi_bus_attach+0x84/0x300 acpi_bus_scan+0x74/0x220 acpi_scan_rescan_bus+0x54/0x88 acpi_device_hotplug+0x208/0x478 acpi_hotplug_work_fn+0x2c/0x50 process_one_work+0x15c/0x3c0 worker_thread+0x2ec/0x400 kthread+0x120/0x130 ret_from_fork+0x10/0x20 Fix it by passing the CPU enabled mask instead of the CPU possible mask to set_cpu_enabled(). Fixes: 51c4767503d5 ("Merge tag 'bitmap-6.11-rc1' of https://github.com:/norov/linux") Signed-off-by: Gavin Shan Reviewed-by: Jonathan Cameron Signed-off-by: Yury Norov --- include/linux/cpumask.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 801a7e524113..53158de44b83 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -1037,7 +1037,7 @@ void init_cpu_online(const struct cpumask *src); assign_bit(cpumask_check(cpu), cpumask_bits(mask), (val)) #define set_cpu_possible(cpu, possible) assign_cpu((cpu), &__cpu_possible_mask, (possible)) -#define set_cpu_enabled(cpu, enabled) assign_cpu((cpu), &__cpu_possible_mask, (enabled)) +#define set_cpu_enabled(cpu, enabled) assign_cpu((cpu), &__cpu_enabled_mask, (enabled)) #define set_cpu_present(cpu, present) assign_cpu((cpu), &__cpu_present_mask, (present)) #define set_cpu_active(cpu, active) assign_cpu((cpu), &__cpu_active_mask, (active)) #define set_cpu_dying(cpu, dying) assign_cpu((cpu), &__cpu_dying_mask, (dying)) -- 2.49.0