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Commit 44744bb3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 959dc258 b3f20785

kernel/events/core.c

+22 −1
Original line number Diff line number Diff line
@@ -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 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	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 @@ static const struct file_operations perf_fops = { 
	.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,

};

kernel/kprobes.c

+12 −1
Original line number Diff line number Diff line
@@ -1778,6 +1778,17 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) 
	unsigned long hash, flags = 0;

	struct kretprobe_instance *ri;



	/*

	 * 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);