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ACPI: processor_idle: Mark LPI enter functions as __cpuidle

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When function tracing or Kprobes is enabled, entering an ACPI Low
Power Idle (LPI) state triggers the following RCU splat:

  RCU not on for: acpi_idle_lpi_enter+0x4/0xd8
  WARNING: CPU: 8 PID: 0 at include/linux/trace_recursion.h:162 function_trace_call+0x1e8/0x228

The acpi_idle_lpi_enter() function is invoked within the cpuidle
path after RCU has already been disabled for the current local CPU.
Consequently, ftrace's function_trace_call() expects RCU to be
actively watching before recording trace data, emitting a warning
if it is not.

Fix this by annotating acpi_idle_lpi_enter(), the generic __weak
stub, and the RISC-V implementation of acpi_processor_ffh_lpi_enter()
with __cpuidle. This moves these functions into the '.cpuidle.text'
section, implicitly disabling ftrace instrumentation (notrace) along
this sensitive path and preventing trace-induced RCU warnings during
idle entry.

Fixes: a36a7fecfe ("ACPI / processor_idle: Add support for Low Power Idle(LPI) states")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Acked-by: lihuisong@huawei.com
Link: https://patch.msgid.link/20260616072617.2272-1-lirongqing@baidu.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Li RongQing 2026-06-16 15:26:17 +08:00 committed by Rafael J. Wysocki
parent eed451031f
commit 956ca5d72c
2 changed files with 3 additions and 3 deletions
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4
drivers/acpi/processor_idle.c
View File

@ -1143,7 +1143,7 @@ static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
return 0;
}
int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
int __weak __cpuidle acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
{
return -ENODEV;
}
@ -1156,7 +1156,7 @@ int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
*
* Return: 0 for success or negative value for error
*/
static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
static int __cpuidle acpi_idle_lpi_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
struct acpi_processor *pr;

2
drivers/acpi/riscv/cpuidle.c
View File

@ -66,7 +66,7 @@ int acpi_processor_ffh_lpi_probe(unsigned int cpu)
return acpi_cpu_init_idle(cpu);
}
int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
int __cpuidle acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
{
u32 state = lpi->address;