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Revision 8ad9219e08af12a5652892e273336dbd31b25b03 authored by Stephane Eranian on 17 January 2014, 15:34:06 UTC, committed by Arnaldo Carvalho de Melo on 20 January 2014, 19:19:09 UTC 
perf stat: Fix memory corruption of xyarray when cpumask is used
 
This patch fixes a memory corruption problem with the xyarray when the
evsel fds get closed at the end of the run_perf_stat() call.

It could be triggered with:

 # perf stat -a -e power/energy-cores/ ls

When cpumask are used by events (.e.g, RAPL or uncores) then the evsel
fds are allocated based on the actual number of CPUs monitored. That
number can be smaller than the total number of CPUs on the system.

The problem arises at the end by perf stat closes the fds twice. When
fds are closed, their entry in the xyarray are set to -1.

The first close() on the evsel is made from __run_perf_stat() and it
uses the actual number of CPUS for the event which is how the xyarray
was allocated for.

The second is from perf_evlist_close() but that one is on the total
number of CPUs in the system, so it assume the xyarray was allocated to
cover it. However it was not, and some writes corrupt memory.

The fix is in perf_evlist_close() is to first try with the evsel->cpus
if present, if not use the evlist->cpus. That fixes the problem.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389972846-6566-3-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1 parent de256a4
Raw File
mq_sysctl.c 
/*
 *  Copyright (C) 2007 IBM Corporation
 *
 *  Author: Cedric Le Goater <clg@fr.ibm.com>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation, version 2 of the
 *  License.
 */

#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/sysctl.h>

#ifdef CONFIG_PROC_SYSCTL
static void *get_mq(ctl_table *table)
{
	char *which = table->data;
	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
	which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
	return which;
}

static int proc_mq_dointvec_minmax(ctl_table *table, int write,
	void __user *buffer, size_t *lenp, loff_t *ppos)
{
	struct ctl_table mq_table;
	memcpy(&mq_table, table, sizeof(mq_table));
	mq_table.data = get_mq(table);

	return proc_dointvec_minmax(&mq_table, write, buffer,
					lenp, ppos);
}
#else
#define proc_mq_dointvec_minmax NULL
#endif

static int msg_queues_limit_min = MIN_QUEUESMAX;
static int msg_queues_limit_max = HARD_QUEUESMAX;

static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;

static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;

static ctl_table mq_sysctls[] = {
	{
		.procname	= "queues_max",
		.data		= &init_ipc_ns.mq_queues_max,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_mq_dointvec_minmax,
		.extra1		= &msg_queues_limit_min,
		.extra2		= &msg_queues_limit_max,
	},
	{
		.procname	= "msg_max",
		.data		= &init_ipc_ns.mq_msg_max,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_mq_dointvec_minmax,
		.extra1		= &msg_max_limit_min,
		.extra2		= &msg_max_limit_max,
	},
	{
		.procname	= "msgsize_max",
		.data		= &init_ipc_ns.mq_msgsize_max,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_mq_dointvec_minmax,
		.extra1		= &msg_maxsize_limit_min,
		.extra2		= &msg_maxsize_limit_max,
	},
	{
		.procname	= "msg_default",
		.data		= &init_ipc_ns.mq_msg_default,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_mq_dointvec_minmax,
		.extra1		= &msg_max_limit_min,
		.extra2		= &msg_max_limit_max,
	},
	{
		.procname	= "msgsize_default",
		.data		= &init_ipc_ns.mq_msgsize_default,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_mq_dointvec_minmax,
		.extra1		= &msg_maxsize_limit_min,
		.extra2		= &msg_maxsize_limit_max,
	},
	{}
};

static ctl_table mq_sysctl_dir[] = {
	{
		.procname	= "mqueue",
		.mode		= 0555,
		.child		= mq_sysctls,
	},
	{}
};

static ctl_table mq_sysctl_root[] = {
	{
		.procname	= "fs",
		.mode		= 0555,
		.child		= mq_sysctl_dir,
	},
	{}
};

struct ctl_table_header *mq_register_sysctl_table(void)
{
	return register_sysctl_table(mq_sysctl_root);
}
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