4ab0a9409a
Impact: fix debug_smp_processor_id() for CONFIG_CPUMASK_OFFSTACK=y The scheduler now uses the new cpumask API, which deals up to nr_cpumask_bits, whereas the API used NR_CPUS bits. If CONFIG_CPUMASK_OFFSTACK=y these two are not equal, so the top bits are undefined. Leading to bug 12518 "BUG: using smp_processor_id() in preemptible [00000000] code: dellWirelessCtl/..." The fix is simple: use the modern API in the check. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
55 lines
1.1 KiB
C
55 lines
1.1 KiB
C
/*
|
|
* lib/smp_processor_id.c
|
|
*
|
|
* DEBUG_PREEMPT variant of smp_processor_id().
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/sched.h>
|
|
|
|
notrace unsigned int debug_smp_processor_id(void)
|
|
{
|
|
unsigned long preempt_count = preempt_count();
|
|
int this_cpu = raw_smp_processor_id();
|
|
|
|
if (likely(preempt_count))
|
|
goto out;
|
|
|
|
if (irqs_disabled())
|
|
goto out;
|
|
|
|
/*
|
|
* Kernel threads bound to a single CPU can safely use
|
|
* smp_processor_id():
|
|
*/
|
|
if (cpumask_equal(¤t->cpus_allowed, cpumask_of(this_cpu)))
|
|
goto out;
|
|
|
|
/*
|
|
* It is valid to assume CPU-locality during early bootup:
|
|
*/
|
|
if (system_state != SYSTEM_RUNNING)
|
|
goto out;
|
|
|
|
/*
|
|
* Avoid recursion:
|
|
*/
|
|
preempt_disable_notrace();
|
|
|
|
if (!printk_ratelimit())
|
|
goto out_enable;
|
|
|
|
printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
|
|
"code: %s/%d\n",
|
|
preempt_count() - 1, current->comm, current->pid);
|
|
print_symbol("caller is %s\n", (long)__builtin_return_address(0));
|
|
dump_stack();
|
|
|
|
out_enable:
|
|
preempt_enable_no_resched_notrace();
|
|
out:
|
|
return this_cpu;
|
|
}
|
|
|
|
EXPORT_SYMBOL(debug_smp_processor_id);
|
|
|