Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"A kprobes and a perf compat ioctl fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Handle compat ioctl
kprobes: Skip kretprobe hit in NMI context to avoid deadlock
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1cf24b3..f9c1ed0 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -41,6 +41,7 @@
#include <linux/cgroup.h>
#include <linux/module.h>
#include <linux/mman.h>
+#include <linux/compat.h>
#include "internal.h"
@@ -3717,6 +3718,26 @@
return 0;
}
+#ifdef CONFIG_COMPAT
+static long perf_compat_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ switch (_IOC_NR(cmd)) {
+ case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
+ case _IOC_NR(PERF_EVENT_IOC_ID):
+ /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
+ if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
+ cmd &= ~IOCSIZE_MASK;
+ cmd |= sizeof(void *) << IOCSIZE_SHIFT;
+ }
+ break;
+ }
+ return perf_ioctl(file, cmd, arg);
+}
+#else
+# define perf_compat_ioctl NULL
+#endif
+
int perf_event_task_enable(void)
{
struct perf_event *event;
@@ -4222,7 +4243,7 @@
.read = perf_read,
.poll = perf_poll,
.unlocked_ioctl = perf_ioctl,
- .compat_ioctl = perf_ioctl,
+ .compat_ioctl = perf_compat_ioctl,
.mmap = perf_mmap,
.fasync = perf_fasync,
};
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 734e9a7..3995f54 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1778,7 +1778,18 @@
unsigned long hash, flags = 0;
struct kretprobe_instance *ri;
- /*TODO: consider to only swap the RA after the last pre_handler fired */
+ /*
+ * To avoid deadlocks, prohibit return probing in NMI contexts,
+ * just skip the probe and increase the (inexact) 'nmissed'
+ * statistical counter, so that the user is informed that
+ * something happened:
+ */
+ if (unlikely(in_nmi())) {
+ rp->nmissed++;
+ return 0;
+ }
+
+ /* TODO: consider to only swap the RA after the last pre_handler fired */
hash = hash_ptr(current, KPROBE_HASH_BITS);
raw_spin_lock_irqsave(&rp->lock, flags);
if (!hlist_empty(&rp->free_instances)) {
