On 03/02/2016 05:18 AM, Michal Hocko wrote:
On Wed 02-03-16 19:36:26, Hidehiro Kawai wrote:
[...]
+void nmi_panic(struct pt_regs *regs, const char *fmt, ...)
Do we really need vargs? All the current users seem to be OK with a
simple string. This makes the code slightly more complicated without any
apparent reason.
+{
+ static char buf[1024]; /* protected by panic_cpu */
I am also not too happy with this additional stack allocation.
panic() itself takes varargs. Can those be passed on ?
I understand this would need something like vpanic(), so
maybe that isn't feasible.
Dropping the format, at least for now, might be a simpler option.
Guenter
+ va_list args;
+ int old_cpu, cpu;
+
+ cpu = raw_smp_processor_id();
+ old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
+
+ if (old_cpu == PANIC_CPU_INVALID) {
+ va_start(args, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);
+
+ panic("%s", buf);
+ } else if (old_cpu != cpu)
+ nmi_panic_self_stop(regs);
+}
+EXPORT_SYMBOL(nmi_panic);
+
/**
* panic - halt the system
* @fmt: The text string to print
