[GIT PULL 0/6] perf/urgent fixes and improvements

[GIT PULL 0/6] perf/urgent fixes and improvements

[Arnaldo Carvalho de Melo]

Hi Ingo,

        Please consider pulling from:

git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 perf/urgent

Regards,

- Arnaldo

Arnaldo Carvalho de Melo (4):
  perf sched: Fix allocation result check
  perf tools: Emit clearer message for sys_perf_event_open ENOENT return
  perf evsel: Support perf_evsel__open(cpus > 1 && threads > 1)
  perf session: Fix infinite loop in __perf_session__process_events

David Ahern (1):
  perf stat: better error message for unsupported events

Jiri Pirko (1):
  perf sched: Use PTHREAD_STACK_MIN to avoid pthread_attr_setstacksize() fail

 tools/perf/builtin-record.c |    3 +
 tools/perf/builtin-sched.c  |    5 +-
 tools/perf/builtin-stat.c   |    2 +
 tools/perf/builtin-test.c   |  110 +++++++++++++++++++++++++++++++++++++++++++
 tools/perf/builtin-top.c    |    2 +
 tools/perf/util/evsel.c     |   82 +++++++++++++++++++-------------
 tools/perf/util/session.c   |    2 +-
 7 files changed, 170 insertions(+), 36 deletions(-)

[PATCH 1/6] perf sched: Fix allocation result check

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

Bug introduced in ce47dc56.

Reported-by: Mike Galbraith <efault@gmx.de>
Cc: Chris Samuel <chris@csamuel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-sched.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 7a4ebeb..54024d2 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1861,7 +1861,7 @@ static int __cmd_record(int argc, const char **argv)
 	rec_argc = ARRAY_SIZE(record_args) + argc - 1;
 	rec_argv = calloc(rec_argc + 1, sizeof(char *));
 
-	if (rec_argv)
+	if (rec_argv == NULL)
 		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(record_args); i++)
-- 
1.6.2.5

[PATCH 2/6] perf stat: better error message for unsupported events

[Arnaldo Carvalho de Melo]

From: David Ahern <daahern@cisco.com>

For unsupported events (e.g., H/W events when running in a VM)
perf stat currently fails with the error message:

      Error: open_counter returned with 2 (No such file or directory).
    /bin/dmesg may provide additional information.

      Fatal: Not all events could be opened.

dmesg is of no help and it is not clear as to why it fails to
open the counter. This patch changes the error message to

      Error: cache-misses event is not supported.
      Fatal: Not all events could be opened.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: a.p.zijlstra@chello.nl
LPU-Reference: <1294597272-17335-1-git-send-email-daahern@cisco.com>
Signed-off-by: David Ahern <daahern@cisco.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-stat.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2dfcb61..c385a63 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -316,6 +316,8 @@ static int run_perf_stat(int argc __used, const char **argv)
 				      "\t Consider tweaking"
 				      " /proc/sys/kernel/perf_event_paranoid or running as root.",
 				      system_wide ? "system-wide " : "");
+			} else if (errno == ENOENT) {
+				error("%s event is not supported. ", event_name(counter));
 			} else {
 				error("open_counter returned with %d (%s). "
 				      "/bin/dmesg may provide additional information.\n",
-- 
1.6.2.5

[PATCH 3/6] perf tools: Emit clearer message for sys_perf_event_open ENOENT return

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

Improve sys_perf_event_open ENOENT return handling in top and record, just
like 5a3446b does for stat.

Cc: David Ahern <daahern@cisco.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-record.c |    3 +++
 tools/perf/builtin-top.c    |    2 ++
 2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 7bc0490..7069bd3 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -331,6 +331,9 @@ try_again:
 			else if (err ==  ENODEV && cpu_list) {
 				die("No such device - did you specify"
 					" an out-of-range profile CPU?\n");
+			} else if (err == ENOENT) {
+				die("%s event is not supported. ",
+				     event_name(evsel));
 			} else if (err == EINVAL && sample_id_all_avail) {
 				/*
 				 * Old kernel, no attr->sample_id_type_all field
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1e67ab9..6ce4042 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1247,6 +1247,8 @@ try_again:
 				die("Permission error - are you root?\n"
 					"\t Consider tweaking"
 					" /proc/sys/kernel/perf_event_paranoid.\n");
+			if (err == ENOENT)
+				die("%s event is not supported. ", event_name(evsel));
 			/*
 			 * If it's cycles then fall back to hrtimer
 			 * based cpu-clock-tick sw counter, which
-- 
1.6.2.5

Re: [PATCH 3/6] perf tools: Emit clearer message for sys_perf_event_open ENOENT return

[David Ahern]

On 01/10/11 17:28, Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> Improve sys_perf_event_open ENOENT return handling in top and record, just
> like 5a3446b does for stat.
> 
> Cc: David Ahern <daahern@cisco.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Stephane Eranian <eranian@google.com>
> Cc: Tom Zanussi <tzanussi@gmail.com>
> LKML-Reference: <new-submission>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/perf/builtin-record.c |    3 +++
>  tools/perf/builtin-top.c    |    2 ++
>  2 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 7bc0490..7069bd3 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -331,6 +331,9 @@ try_again:
>  			else if (err ==  ENODEV && cpu_list) {
>  				die("No such device - did you specify"
>  					" an out-of-range profile CPU?\n");
> +			} else if (err == ENOENT) {
> +				die("%s event is not supported. ",
> +				     event_name(evsel));

I think this interferes with the fallback from hardware profiling to
software profiling. .e.g., in a VM with no PMU.

David


>  			} else if (err == EINVAL && sample_id_all_avail) {
>  				/*
>  				 * Old kernel, no attr->sample_id_type_all field
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 1e67ab9..6ce4042 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1247,6 +1247,8 @@ try_again:
>  				die("Permission error - are you root?\n"
>  					"\t Consider tweaking"
>  					" /proc/sys/kernel/perf_event_paranoid.\n");
> +			if (err == ENOENT)
> +				die("%s event is not supported. ", event_name(evsel));
>  			/*
>  			 * If it's cycles then fall back to hrtimer
>  			 * based cpu-clock-tick sw counter, which

Re: [PATCH 3/6] perf tools: Emit clearer message for sys_perf_event_open ENOENT return

[Arnaldo Carvalho de Melo]

Em Tue, Jan 11, 2011 at 11:40:23AM -0700, David Ahern escreveu:
> 
> 
> On 01/10/11 17:28, Arnaldo Carvalho de Melo wrote:
> > From: Arnaldo Carvalho de Melo <acme@redhat.com>
> > 
> > Improve sys_perf_event_open ENOENT return handling in top and record, just
> > like 5a3446b does for stat.
> > 
> > Cc: David Ahern <daahern@cisco.com>
> > Cc: Frederic Weisbecker <fweisbec@gmail.com>
> > Cc: Ingo Molnar <mingo@elte.hu>
> > Cc: Mike Galbraith <efault@gmx.de>
> > Cc: Paul Mackerras <paulus@samba.org>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Stephane Eranian <eranian@google.com>
> > Cc: Tom Zanussi <tzanussi@gmail.com>
> > LKML-Reference: <new-submission>
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> > ---
> >  tools/perf/builtin-record.c |    3 +++
> >  tools/perf/builtin-top.c    |    2 ++
> >  2 files changed, 5 insertions(+), 0 deletions(-)
> > 
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index 7bc0490..7069bd3 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -331,6 +331,9 @@ try_again:
> >  			else if (err ==  ENODEV && cpu_list) {
> >  				die("No such device - did you specify"
> >  					" an out-of-range profile CPU?\n");
> > +			} else if (err == ENOENT) {
> > +				die("%s event is not supported. ",
> > +				     event_name(evsel));
> 
> I think this interferes with the fallback from hardware profiling to
> software profiling. .e.g., in a VM with no PMU.

Argh, you're right, in both cases (top and record) :-\ Reverting.
 
> David
> 
> 
> >  			} else if (err == EINVAL && sample_id_all_avail) {
> >  				/*
> >  				 * Old kernel, no attr->sample_id_type_all field
> > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> > index 1e67ab9..6ce4042 100644
> > --- a/tools/perf/builtin-top.c
> > +++ b/tools/perf/builtin-top.c
> > @@ -1247,6 +1247,8 @@ try_again:
> >  				die("Permission error - are you root?\n"
> >  					"\t Consider tweaking"
> >  					" /proc/sys/kernel/perf_event_paranoid.\n");
> > +			if (err == ENOENT)
> > +				die("%s event is not supported. ", event_name(evsel));
> >  			/*
> >  			 * If it's cycles then fall back to hrtimer
> >  			 * based cpu-clock-tick sw counter, which

[PATCH 4/6] perf sched: Use PTHREAD_STACK_MIN to avoid pthread_attr_setstacksize() fail

[Arnaldo Carvalho de Melo]

From: Jiri Pirko <jpirko@redhat.com>

on ppc64:
/usr/include/bits/local_lim.h:#define PTHREAD_STACK_MIN	131072

therefore following set of commands:

gives:
perf.2.6.37test: builtin-sched.c:493: create_tasks: Assertion `!(err)' failed.

So make sure we do not set stack size lower than PTHREAD_STACK_MIN.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20110110160417.GB2685@psychotron.brq.redhat.com>
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-sched.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 54024d2..abd4b84 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -489,7 +489,8 @@ static void create_tasks(void)
 
 	err = pthread_attr_init(&attr);
 	BUG_ON(err);
-	err = pthread_attr_setstacksize(&attr, (size_t)(16*1024));
+	err = pthread_attr_setstacksize(&attr,
+			(size_t) max(16 * 1024, PTHREAD_STACK_MIN));
 	BUG_ON(err);
 	err = pthread_mutex_lock(&start_work_mutex);
 	BUG_ON(err);
-- 
1.6.2.5

[PATCH 5/6] perf evsel: Support perf_evsel__open(cpus > 1 && threads > 1)

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

And a test for it:

[acme@felicio linux]$ perf test
 1: vmlinux symtab matches kallsyms: Ok
 2: detect open syscall event: Ok
 3: detect open syscall event on all cpus: Ok
[acme@felicio linux]$

Translating C the test does:

1. generates different number of open syscalls on each CPU
   by using sched_setaffinity
2. Verifies that the expected number of events is generated
   on each CPU

It works as expected.

LKML-Reference: <new-submission>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-test.c |  110 +++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/evsel.c   |   82 ++++++++++++++++++++-------------
 2 files changed, 159 insertions(+), 33 deletions(-)

diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c
index e12753f..ed56961 100644
--- a/tools/perf/builtin-test.c
+++ b/tools/perf/builtin-test.c
@@ -234,6 +234,7 @@ out:
 	return err;
 }
 
+#include "util/cpumap.h"
 #include "util/evsel.h"
 #include <sys/types.h>
 
@@ -321,6 +322,111 @@ out_thread_map_delete:
 	return err;
 }
 
+#include <sched.h>
+
+static int test__open_syscall_event_on_all_cpus(void)
+{
+	int err = -1, fd, cpu;
+	struct thread_map *threads;
+	struct cpu_map *cpus;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr;
+	unsigned int nr_open_calls = 111, i;
+	cpu_set_t *cpu_set;
+	size_t cpu_set_size;
+	int id = trace_event__id("sys_enter_open");
+
+	if (id < 0) {
+		pr_debug("is debugfs mounted on /sys/kernel/debug?\n");
+		return -1;
+	}
+
+	threads = thread_map__new(-1, getpid());
+	if (threads == NULL) {
+		pr_debug("thread_map__new\n");
+		return -1;
+	}
+
+	cpus = cpu_map__new(NULL);
+	if (threads == NULL) {
+		pr_debug("thread_map__new\n");
+		return -1;
+	}
+
+	cpu_set = CPU_ALLOC(cpus->nr);
+
+	if (cpu_set == NULL)
+		goto out_thread_map_delete;
+
+	cpu_set_size = CPU_ALLOC_SIZE(cpus->nr);
+	CPU_ZERO_S(cpu_set_size, cpu_set);
+
+	memset(&attr, 0, sizeof(attr));
+	attr.type = PERF_TYPE_TRACEPOINT;
+	attr.config = id;
+	evsel = perf_evsel__new(&attr, 0);
+	if (evsel == NULL) {
+		pr_debug("perf_evsel__new\n");
+		goto out_cpu_free;
+	}
+
+	if (perf_evsel__open(evsel, cpus, threads) < 0) {
+		pr_debug("failed to open counter: %s, "
+			 "tweak /proc/sys/kernel/perf_event_paranoid?\n",
+			 strerror(errno));
+		goto out_evsel_delete;
+	}
+
+	for (cpu = 0; cpu < cpus->nr; ++cpu) {
+		unsigned int ncalls = nr_open_calls + cpu;
+
+		CPU_SET(cpu, cpu_set);
+		sched_setaffinity(0, cpu_set_size, cpu_set);
+		for (i = 0; i < ncalls; ++i) {
+			fd = open("/etc/passwd", O_RDONLY);
+			close(fd);
+		}
+		CPU_CLR(cpu, cpu_set);
+	}
+
+	/*
+	 * Here we need to explicitely preallocate the counts, as if
+	 * we use the auto allocation it will allocate just for 1 cpu,
+	 * as we start by cpu 0.
+	 */
+	if (perf_evsel__alloc_counts(evsel, cpus->nr) < 0) {
+		pr_debug("perf_evsel__alloc_counts(ncpus=%d)\n", cpus->nr);
+		goto out_close_fd;
+	}
+
+	for (cpu = 0; cpu < cpus->nr; ++cpu) {
+		unsigned int expected;
+
+		if (perf_evsel__read_on_cpu(evsel, cpu, 0) < 0) {
+			pr_debug("perf_evsel__open_read_on_cpu\n");
+			goto out_close_fd;
+		}
+
+		expected = nr_open_calls + cpu;
+		if (evsel->counts->cpu[cpu].val != expected) {
+			pr_debug("perf_evsel__read_on_cpu: expected to intercept %d calls on cpu %d, got %Ld\n",
+				 expected, cpu, evsel->counts->cpu[cpu].val);
+			goto out_close_fd;
+		}
+	}
+
+	err = 0;
+out_close_fd:
+	perf_evsel__close_fd(evsel, 1, threads->nr);
+out_evsel_delete:
+	perf_evsel__delete(evsel);
+out_cpu_free:
+	CPU_FREE(cpu_set);
+out_thread_map_delete:
+	thread_map__delete(threads);
+	return err;
+}
+
 static struct test {
 	const char *desc;
 	int (*func)(void);
@@ -334,6 +440,10 @@ static struct test {
 		.func = test__open_syscall_event,
 	},
 	{
+		.desc = "detect open syscall event on all cpus",
+		.func = test__open_syscall_event_on_all_cpus,
+	},
+	{
 		.func = NULL,
 	},
 };
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1a5591d..f5cfed6 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -127,59 +127,75 @@ int __perf_evsel__read(struct perf_evsel *evsel,
 	return 0;
 }
 
-int perf_evsel__open_per_cpu(struct perf_evsel *evsel, struct cpu_map *cpus)
+static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
+			      struct thread_map *threads)
 {
-	int cpu;
+	int cpu, thread;
 
-	if (evsel->fd == NULL && perf_evsel__alloc_fd(evsel, cpus->nr, 1) < 0)
+	if (evsel->fd == NULL &&
+	    perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
 		return -1;
 
 	for (cpu = 0; cpu < cpus->nr; cpu++) {
-		FD(evsel, cpu, 0) = sys_perf_event_open(&evsel->attr, -1,
-							cpus->map[cpu], -1, 0);
-		if (FD(evsel, cpu, 0) < 0)
-			goto out_close;
+		for (thread = 0; thread < threads->nr; thread++) {
+			FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
+								     threads->map[thread],
+								     cpus->map[cpu], -1, 0);
+			if (FD(evsel, cpu, thread) < 0)
+				goto out_close;
+		}
 	}
 
 	return 0;
 
 out_close:
-	while (--cpu >= 0) {
-		close(FD(evsel, cpu, 0));
-		FD(evsel, cpu, 0) = -1;
-	}
+	do {
+		while (--thread >= 0) {
+			close(FD(evsel, cpu, thread));
+			FD(evsel, cpu, thread) = -1;
+		}
+		thread = threads->nr;
+	} while (--cpu >= 0);
 	return -1;
 }
 
-int perf_evsel__open_per_thread(struct perf_evsel *evsel, struct thread_map *threads)
+static struct {
+	struct cpu_map map;
+	int cpus[1];
+} empty_cpu_map = {
+	.map.nr	= 1,
+	.cpus	= { -1, },
+};
+
+static struct {
+	struct thread_map map;
+	int threads[1];
+} empty_thread_map = {
+	.map.nr	 = 1,
+	.threads = { -1, },
+};
+
+int perf_evsel__open(struct perf_evsel *evsel,
+		     struct cpu_map *cpus, struct thread_map *threads)
 {
-	int thread;
-
-	if (evsel->fd == NULL && perf_evsel__alloc_fd(evsel, 1, threads->nr))
-		return -1;
 
-	for (thread = 0; thread < threads->nr; thread++) {
-		FD(evsel, 0, thread) = sys_perf_event_open(&evsel->attr,
-							   threads->map[thread], -1, -1, 0);
-		if (FD(evsel, 0, thread) < 0)
-			goto out_close;
+	if (cpus == NULL) {
+		/* Work around old compiler warnings about strict aliasing */
+		cpus = &empty_cpu_map.map;
 	}
 
-	return 0;
+	if (threads == NULL)
+		threads = &empty_thread_map.map;
 
-out_close:
-	while (--thread >= 0) {
-		close(FD(evsel, 0, thread));
-		FD(evsel, 0, thread) = -1;
-	}
-	return -1;
+	return __perf_evsel__open(evsel, cpus, threads);
 }
 
-int perf_evsel__open(struct perf_evsel *evsel, 
-		     struct cpu_map *cpus, struct thread_map *threads)
+int perf_evsel__open_per_cpu(struct perf_evsel *evsel, struct cpu_map *cpus)
 {
-	if (threads == NULL)
-		return perf_evsel__open_per_cpu(evsel, cpus);
+	return __perf_evsel__open(evsel, cpus, &empty_thread_map.map);
+}
 
-	return perf_evsel__open_per_thread(evsel, threads);
+int perf_evsel__open_per_thread(struct perf_evsel *evsel, struct thread_map *threads)
+{
+	return __perf_evsel__open(evsel, &empty_cpu_map.map, threads);
 }
-- 
1.6.2.5

[PATCH 6/6] perf session: Fix infinite loop in __perf_session__process_events

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

In this if statement:

        if (head + event->header.size >= mmap_size) {
                if (mmaps[map_idx]) {
                        munmap(mmaps[map_idx], mmap_size);
                        mmaps[map_idx] = NULL;
                }

                page_offset = page_size * (head / page_size);
                file_offset += page_offset;
                head -= page_offset;
                goto remap;
        }

With, for instance, these values:

head=2992
event->header.size=48
mmap_size=3040

We end up endlessly looping back to remap. Off by one.

Problem introduced in 55b4462.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
Reported-by: David Ahern <daahern@cisco.com>
Bisected-by: David Ahern <daahern@cisco.com>
Tested-by: David Ahern <daahern@cisco.com>
Cc: David Ahern <daahern@cisco.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/session.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 6fb4694..313dac2 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1007,7 +1007,7 @@ more:
 	if (size == 0)
 		size = 8;
 
-	if (head + event->header.size >= mmap_size) {
+	if (head + event->header.size > mmap_size) {
 		if (mmaps[map_idx]) {
 			munmap(mmaps[map_idx], mmap_size);
 			mmaps[map_idx] = NULL;
-- 
1.6.2.5

Re: [GIT PULL 0/6] perf/urgent fixes and improvements

[Ingo Molnar]

* Arnaldo Carvalho de Melo <acme@infradead.org> wrote:

> Hi Ingo,
> 
>         Please consider pulling from:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 perf/urgent
> 
> Regards,
> 
> - Arnaldo
> 
> Arnaldo Carvalho de Melo (4):
>   perf sched: Fix allocation result check
>   perf tools: Emit clearer message for sys_perf_event_open ENOENT return
>   perf evsel: Support perf_evsel__open(cpus > 1 && threads > 1)
>   perf session: Fix infinite loop in __perf_session__process_events
> 
> David Ahern (1):
>   perf stat: better error message for unsupported events
> 
> Jiri Pirko (1):
>   perf sched: Use PTHREAD_STACK_MIN to avoid pthread_attr_setstacksize() fail
> 
>  tools/perf/builtin-record.c |    3 +
>  tools/perf/builtin-sched.c  |    5 +-
>  tools/perf/builtin-stat.c   |    2 +
>  tools/perf/builtin-test.c   |  110 +++++++++++++++++++++++++++++++++++++++++++
>  tools/perf/builtin-top.c    |    2 +
>  tools/perf/util/evsel.c     |   82 +++++++++++++++++++-------------
>  tools/perf/util/session.c   |    2 +-
>  7 files changed, 170 insertions(+), 36 deletions(-)

Pulled, thanks a lot Arnaldo!

	Ingo