[tip:perf/core] perf evlist: Fix mmap pages rounding to power of 2

tip-bot for Adrian Hunter
2013-12-11T11:05:24Z

Commit-ID: 1dbfa9387b397f2c4b8c65411b3e3fdf9284d2b1
Gitweb: http://git.kernel.org/tip/1dbfa9387b397f2c4b8c65411b3e3fdf9284d2b1
Author: Adrian Hunter <adrian.hunter@intel.com>
AuthorDate: Mon, 9 Dec 2013 15:18:39 +0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 9 Dec 2013 15:18:05 -0300

perf evlist: Fix mmap pages rounding to power of 2

'next_pow2()' only works for 'unsigned int' but the argument is
'unsigned long'. Checking for values less than (1 << 31) ensures that
'next_pow2()' is not passed a value out of range but lets anything else
go through unvalidated.

As a result mmap_pages of zero is used e.g.

perf record -v -m2147483649 uname
mmap size 0B
failed to mmap with 22 (Invalid argument)

Fixed:

perf record -m2147483649 uname
rounding mmap pages size to 17592186044416 bytes (4294967296 pages)
Invalid argument for --mmap_pages/-m

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1386595120-22978-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/evlist.c | 6 ++++--
tools/perf/util/util.h | 12 ++++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 98ec96b..af25055 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -734,9 +734,11 @@ static long parse_pages_arg(const char *str, unsigned long min,

if (pages == 0 && min == 0) {
/* leave number of pages at 0 */
- } else if (pages < (1UL << 31) && !is_power_of_2(pages)) {
+ } else if (!is_power_of_2(pages)) {
/* round pages up to next power of 2 */
- pages = next_pow2(pages);
+ pages = next_pow2_l(pages);
+ if (!pages)
+ return -EINVAL;
pr_info("rounding mmap pages size to %lu bytes (%lu pages)\n",
pages * page_size, pages);
}
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index adb39f2..659abf3 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -73,6 +73,7 @@
#include <sys/ttydefaults.h>
#include <lk/debugfs.h>
#include <termios.h>
+#include <linux/bitops.h>

extern const char *graph_line;
extern const char *graph_dotted_line;
@@ -281,6 +282,17 @@ static inline unsigned next_pow2(unsigned x)
return 1ULL << (32 - __builtin_clz(x - 1));
}

+static inline unsigned long next_pow2_l(unsigned long x)
+{
+#if BITS_PER_LONG == 64
+ if (x <= (1UL << 31))
+ return next_pow2(x);
+ return (unsigned long)next_pow2(x >> 32) << 32;
+#else
+ return next_pow2(x);
+#endif
+}
+
size_t hex_width(u64 v);
int hex2u64(const char *ptr, u64 *val);