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Commit 0764771d authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: More paranoia settings 



Rename the perf_counter_priv knob to perf_counter_paranoia (because
priv can be read as private, as opposed to privileged) and provide
one more level:

 0 - permissive
 1 - restrict cpu counters to privilidged contexts
 2 - restrict kernel-mode code counting and profiling

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 106b506c

include/linux/perf_counter.h

+1 −1
Original line number Diff line number Diff line
@@ -648,7 +648,7 @@ struct perf_callchain_entry { 


extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);



extern int sysctl_perf_counter_priv;

extern int sysctl_perf_counter_paranoid;

extern int sysctl_perf_counter_mlock;

extern int sysctl_perf_counter_limit;

kernel/perf_counter.c

+23 −2
Original line number Diff line number Diff line
@@ -43,7 +43,23 @@ static atomic_t nr_counters __read_mostly; 
static atomic_t nr_mmap_counters __read_mostly;

static atomic_t nr_comm_counters __read_mostly;



int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */

/*

 * 0 - not paranoid

 * 1 - disallow cpu counters to unpriv

 * 2 - disallow kernel profiling to unpriv

 */

int sysctl_perf_counter_paranoid __read_mostly; /* do we need to be privileged */



static inline bool perf_paranoid_cpu(void)

{

	return sysctl_perf_counter_paranoid > 0;

}



static inline bool perf_paranoid_kernel(void)

{

	return sysctl_perf_counter_paranoid > 1;

}



int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */

int sysctl_perf_counter_limit __read_mostly = 100000; /* max NMIs per second */
@@ -1385,7 +1401,7 @@ static struct perf_counter_context *find_get_context(pid_t pid, int cpu) 
	 */

	if (cpu != -1) {

		/* Must be root to operate on a CPU counter: */

		if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))

		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))

			return ERR_PTR(-EACCES);



		if (cpu < 0 || cpu > num_possible_cpus())
@@ -3618,6 +3634,11 @@ SYSCALL_DEFINE5(perf_counter_open, 
	if (copy_from_user(&attr, attr_uptr, sizeof(attr)) != 0)

		return -EFAULT;



	if (!attr.exclude_kernel) {

		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))

			return -EACCES;

	}



	/*

	 * Get the target context (task or percpu):

	 */

kernel/sysctl.c

+3 −3
Original line number Diff line number Diff line
@@ -916,9 +916,9 @@ static struct ctl_table kern_table[] = { 
#ifdef CONFIG_PERF_COUNTERS

	{

		.ctl_name	= CTL_UNNUMBERED,

		.procname	= "perf_counter_privileged",

		.data		= &sysctl_perf_counter_priv,

		.maxlen		= sizeof(sysctl_perf_counter_priv),

		.procname	= "perf_counter_paranoid",

		.data		= &sysctl_perf_counter_paranoid,

		.maxlen		= sizeof(sysctl_perf_counter_paranoid),

		.mode		= 0644,

		.proc_handler	= &proc_dointvec,

	},