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SubjectRe: [PATCH v2] perf probe: Fix add event failed when 32-bit perf running in 64-bit kernel
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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

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