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From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Jiri Olsa <jolsa@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.9 02/13] Revert "perf tools: Fix PMU term format max value calculation"
Date: Tue, 30 Oct 2018 09:29:12 -0400	[thread overview]
Message-ID: <20181030132923.218124-2-sashal@kernel.org> (raw)
In-Reply-To: <20181030132923.218124-1-sashal@kernel.org>

From: Jiri Olsa <jolsa@kernel.org>

[ Upstream commit 1b9caa10b31dda0866f4028e4bfb923fb6e4072f ]

This reverts commit ac0e2cd555373ae6f8f3a3ad3fbbf5b6d1e7aaaa.

Michael reported an issue with oversized terms values assignment
and I noticed there was actually a misunderstanding of the max
value check in the past.

The above commit's changelog says:

  If bit 21 is set, there is parsing issues as below.

    $ perf stat -a -e uncore_qpi_0/event=0x200002,umask=0x8/
    event syntax error: '..pi_0/event=0x200002,umask=0x8/'
                                      \___ value too big for format, maximum is 511

But there's no issue there, because the event value is distributed
along the value defined by the format. Even if the format defines
separated bit, the value is treated as a continual number, which
should follow the format definition.

In above case it's 9-bit value with last bit separated:
  $ cat uncore_qpi_0/format/event
  config:0-7,21

Hence the value 0x200002 is correctly reported as format violation,
because it exceeds 9 bits. It should have been 0x102 instead, which
sets the 9th bit - the bit 21 of the format.

  $ perf stat -vv -a -e uncore_qpi_0/event=0x102,umask=0x8/
  Using CPUID GenuineIntel-6-2D
  ...
  ------------------------------------------------------------
  perf_event_attr:
    type                             10
    size                             112
    config                           0x200802
    sample_type                      IDENTIFIER
  ...

Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: ac0e2cd55537 ("perf tools: Fix PMU term format max value calculation")
Link: http://lkml.kernel.org/r/20181003072046.29276-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/util/pmu.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index b1474dcadfa2..0f84371d4d6b 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -685,13 +685,14 @@ static void pmu_format_value(unsigned long *format, __u64 value, __u64 *v,
 
 static __u64 pmu_format_max_value(const unsigned long *format)
 {
-	__u64 w = 0;
-	int fbit;
-
-	for_each_set_bit(fbit, format, PERF_PMU_FORMAT_BITS)
-		w |= (1ULL << fbit);
+	int w;
 
-	return w;
+	w = bitmap_weight(format, PERF_PMU_FORMAT_BITS);
+	if (!w)
+		return 0;
+	if (w < 64)
+		return (1ULL << w) - 1;
+	return -1;
 }
 
 /*
-- 
2.17.1


  reply	other threads:[~2018-10-30 13:30 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-30 13:29 [PATCH AUTOSEL 4.9 01/13] bpf: do not blindly change rlimit in reuseport net selftest Sasha Levin
2018-10-30 13:29 ` Sasha Levin [this message]
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 03/13] xfrm: policy: use hlist rcu variants on insert Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 04/13] sparc: Fix single-pcr perf event counter management Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 05/13] sparc64: Make proc_id signed Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 06/13] sched/fair: Fix the min_vruntime update logic in dequeue_entity() Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 07/13] perf cpu_map: Align cpu map synthesized events properly Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 08/13] x86/fpu: Remove second definition of fpu in __fpu__restore_sig() Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 09/13] net: qla3xxx: Remove overflowing shift statement Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 10/13] r8169: fix NAPI handling under high load Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 11/13] selftests: ftrace: Add synthetic event syntax testcase Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 12/13] net: fix pskb_trim_rcsum_slow() with odd trim offset Sasha Levin
2018-10-30 13:29 ` [PATCH AUTOSEL 4.9 13/13] i2c: rcar: cleanup DMA for all kinds of failure Sasha Levin

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