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authorMayank Rungta <mrungta@google.com>2026-07-30 15:00:21 -0700
committerGuenter Roeck <linux@roeck-us.net>2026-08-10 09:00:05 -0700
commitbd26ae0caa20de77328f85a2de4860d8494f1217 (patch)
treea883083d3c68fabe6509e6f97a9e7a686a92bcfb
parentb583ce85417befdc3d8a13458ed9b81e9421b665 (diff)
nmi: Export CPU backtrace APIs for loadable modules
Currently, CPU backtrace functions cannot be called from loadable modules because the underlying helper arch_trigger_cpumask_backtrace() is not exported. Instead of exporting arch_trigger_cpumask_backtrace() individually across every supported architecture, introduce and export a common helper, cpumask_backtrace(), in lib/nmi_backtrace.c. Update the four inline CPU backtrace macros in include/linux/nmi.h to route through this centralized helper. Signed-off-by: Mayank Rungta <mrungta@google.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/r/20260730-export-cpu-backtrace-apis-v1-1-bace8e1cb817@google.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
-rw-r--r--include/linux/nmi.h10
-rw-r--r--lib/nmi_backtrace.c7
2 files changed, 13 insertions, 4 deletions
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index bc1162895f35..a394656bdb6d 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -157,27 +157,29 @@ static inline void touch_nmi_watchdog(void)
* to allow calling code to fall back to some other mechanism:
*/
#ifdef arch_trigger_cpumask_backtrace
+void cpumask_backtrace(const cpumask_t *mask, int exclude_cpu);
+
static inline bool trigger_all_cpu_backtrace(void)
{
- arch_trigger_cpumask_backtrace(cpu_online_mask, -1);
+ cpumask_backtrace(cpu_online_mask, -1);
return true;
}
static inline bool trigger_allbutcpu_cpu_backtrace(int exclude_cpu)
{
- arch_trigger_cpumask_backtrace(cpu_online_mask, exclude_cpu);
+ cpumask_backtrace(cpu_online_mask, exclude_cpu);
return true;
}
static inline bool trigger_cpumask_backtrace(struct cpumask *mask)
{
- arch_trigger_cpumask_backtrace(mask, -1);
+ cpumask_backtrace(mask, -1);
return true;
}
static inline bool trigger_single_cpu_backtrace(int cpu)
{
- arch_trigger_cpumask_backtrace(cpumask_of(cpu), -1);
+ cpumask_backtrace(cpumask_of(cpu), -1);
return true;
}
diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
index a3bfa9360b23..f39c9eca8888 100644
--- a/lib/nmi_backtrace.c
+++ b/lib/nmi_backtrace.c
@@ -19,6 +19,7 @@
#include <linux/stringify.h>
#include <linux/nmi.h>
#include <linux/cpu.h>
+#include <linux/export.h>
#include <linux/sched/debug.h>
#ifdef arch_trigger_cpumask_backtrace
@@ -129,4 +130,10 @@ bool nmi_cpu_backtrace(struct pt_regs *regs)
return false;
}
NOKPROBE_SYMBOL(nmi_cpu_backtrace);
+
+void cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
+{
+ arch_trigger_cpumask_backtrace(mask, exclude_cpu);
+}
+EXPORT_SYMBOL_GPL(cpumask_backtrace);
#endif