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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>
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Raw File
sysctl_net_ipx.c 
/* -*- linux-c -*-
 * sysctl_net_ipx.c: sysctl interface to net IPX subsystem.
 *
 * Begun April 1, 1996, Mike Shaver.
 * Added /proc/sys/net/ipx directory entry (empty =) ). [MS]
 * Added /proc/sys/net/ipx/ipx_pprop_broadcasting - acme March 4, 2001
 */

#include <linux/mm.h>
#include <linux/sysctl.h>
#include <net/net_namespace.h>

#ifndef CONFIG_SYSCTL
#error This file should not be compiled without CONFIG_SYSCTL defined
#endif

/* From af_ipx.c */
extern int sysctl_ipx_pprop_broadcasting;

static struct ctl_table ipx_table[] = {
	{
		.procname	= "ipx_pprop_broadcasting",
		.data		= &sysctl_ipx_pprop_broadcasting,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
	},
	{ },
};

static struct ctl_table_header *ipx_table_header;

void ipx_register_sysctl(void)
{
	ipx_table_header = register_net_sysctl(&init_net, "net/ipx", ipx_table);
}

void ipx_unregister_sysctl(void)
{
	unregister_net_sysctl_table(ipx_table_header);
}
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