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From: Yang Jihong <yangjihong1@huawei.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <peterz@infradead.org>, <mingo@redhat.com>, <acme@kernel.org>,
	<mark.rutland@arm.com>, <alexander.shishkin@linux.intel.com>,
	<jolsa@redhat.com>, <namhyung@kernel.org>, <irogers@google.com>,
	<fche@redhat.com>, <ravi.bangoria@linux.ibm.com>,
	<yao.jin@linux.intel.com>, <srikar@linux.vnet.ibm.com>,
	<Jianlin.Lv@arm.com>, <lihuafei1@huawei.com>,
	<linux-perf-users@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] perf probe: Fix add event failed when 32-bit perf running in 64-bit kernel
Date: Thu, 15 Jul 2021 19:40:57 +0800	[thread overview]
Message-ID: <de8ee605-4376-fc9d-e842-c3f488d673a7@huawei.com> (raw)
In-Reply-To: <20210715180505.11d1209c91d37c239abe65d7@kernel.org>

Hello Hiramatsu,

On 2021/7/15 17:05, Masami Hiramatsu wrote:
> On Thu, 15 Jul 2021 14:37:23 +0800
> Yang Jihong <yangjihong1@huawei.com> wrote:
> 
>> The "address" member  of "struct probe_trace_point" uses long data type.
>> If kernel is 64-bit and perf program is 32-bit, size of "address" variable is
>> 32 bits. As a result, upper 32 bits of address read from kernel are truncated,
>> An error occurs during address comparison in kprobe_warn_out_range function.
>>
>> Before:
>>
>>    # perf probe -a schedule
>>    schedule is out of .text, skip it.
>>      Error: Failed to add events.
>>
>> Solution:
>>    Change data type of "address" variable to u64 and change corresponding
>> address printing and value assignment.
>>
>> After:
>>
>>    # perf.new.new probe -a schedule
>>    Added new event:
>>      probe:schedule       (on schedule)
>>
>>    You can now use it in all perf tools, such as:
>>
>>            perf record -e probe:schedule -aR sleep 1
>>
>>    # perf probe -l
>>      probe:schedule       (on schedule@kernel/sched/core.c)
>>    # perf record -e probe:schedule -aR sleep 1
>>    [ perf record: Woken up 1 times to write data ]
>>    [ perf record: Captured and wrote 0.156 MB perf.data (1366 samples) ]
>>    # perf report --stdio
>>    # To display the perf.data header info, please use --header/--header-only options.
>>    #
>>    #
>>    # Total Lost Samples: 0
>>    #
>>    # Samples: 1K of event 'probe:schedule'
>>    # Event count (approx.): 1366
>>    #
>>    # Overhead  Command          Shared Object      Symbol
>>    # ........  ...............  .................  ............
>>    #
>>         6.22%  migration/0      [kernel.kallsyms]  [k] schedule
>>         6.22%  migration/1      [kernel.kallsyms]  [k] schedule
>>         6.22%  migration/2      [kernel.kallsyms]  [k] schedule
>>         6.22%  migration/3      [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/10     [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/11     [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/12     [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/13     [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/14     [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/15     [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/4      [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/5      [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/6      [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/7      [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/8      [kernel.kallsyms]  [k] schedule
>>         6.15%  migration/9      [kernel.kallsyms]  [k] schedule
>>         0.22%  rcu_sched        [kernel.kallsyms]  [k] schedule
>>    ...
>>    #
>>    # (Cannot load tips.txt file, please install perf!)
>>    #
>>
> 
> OK, this looks good to me :)
> 
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
> 
Thanks for the Acked :)

Jihong

  reply	other threads:[~2021-07-15 11:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15  6:37 [PATCH v2] perf probe: Fix add event failed when 32-bit perf running in 64-bit kernel Yang Jihong
2021-07-15  9:05 ` Masami Hiramatsu
2021-07-15 11:40   ` Yang Jihong [this message]
2021-07-18 12:32   ` Arnaldo Carvalho de Melo

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