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Re: [PATCH v3 2/6] perf probe: Fix list result when neither dwarf nor map can't find symbol

From "Wangnan (F)" <wangnan0@huawei.com>
Newsgroups linux.kernel
Subject Re: [PATCH v3 2/6] perf probe: Fix list result when neither dwarf nor map can't find symbol
Date 2015-08-26 13:10 +0200
Message-ID <q1GKC-3VH-19@gated-at.bofh.it> (permalink)
References <q1GAW-3v0-5@gated-at.bofh.it> <q1GKC-3VH-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Please ignore this one, and use the identical one with shorter title.

Sorry for the noisy.

On 2015/8/26 18:57, Wang Nan wrote:
> 'perf probe -l' reports error if it is unable find symbol through
> address. Here is an example.
>
>   # echo 'p:probe_libc/abs_5 /lib64/libc.so.6:0x5' >
>            /sys/kernel/debug/tracing/uprobe_events
>   # cat /sys/kernel/debug/tracing/uprobe_events
>    p:probe_libc/abs_5 /lib64/libc.so.6:0x0000000000000005
>   # perf probe -l
>     Error: Failed to show event list
>
> Also, this situation triggers a logical inconsistency in
> convert_to_perf_probe_point() that, it returns ENOMEM but actually
> it never try strdup().
>
> This patch removes !tp->module && !is_kprobe condition, so it
> always uses address to build function name if symbol not found.
>
> Test result:
>
>   # perf probe -l
>     probe_libc:abs_5     (on 0x5 in /lib64/libc.so.6)
>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> ---
>   tools/perf/util/probe-event.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 6c7e538..f7bacbb 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1866,7 +1866,7 @@ static int convert_to_perf_probe_point(struct probe_trace_point *tp,
>   	if (tp->symbol) {
>   		pp->function = strdup(tp->symbol);
>   		pp->offset = tp->offset;
> -	} else if (!tp->module && !is_kprobe) {
> +	} else {
>   		ret = e_snprintf(buf, 128, "0x%" PRIx64, (u64)tp->address);
>   		if (ret < 0)
>   			return ret;


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Thread

[PATCH v3 0/6] perf probe, tracing/uprobes: Support probing at absolute address Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:00 +0200
  [PATCH v3 6/6] tracing/uprobes: Do not print '0x (null)' when offset is 0 Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:00 +0200
    [tip:perf/core] tracing/uprobes: Do not print '0x (null)'   when offset is 0 tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-28 08:50 +0200
  [PATCH v3 2/6] perf probe: Fix list result when symbol can't be found Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:00 +0200
    RE: [PATCH v3 2/6] perf probe: Fix list result when symbol can't be  found 平松雅巳 / HIRAMATU,MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2015-08-26 14:30 +0200
    [tip:perf/core] perf probe: Fix list result when symbol can'  t be found tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-28 08:50 +0200
  [PATCH v3 5/6] perf probe: Support probing at absolute address Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:00 +0200
    RE: [PATCH v3 5/6] perf probe: Support probing at absolute address 平松雅巳 / HIRAMATU,MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2015-08-26 14:20 +0200
    [tip:perf/core] perf probe: Support probing at absolute address tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-28 08:50 +0200
  [PATCH v3 4/6] perf probe: Fix error reported when offset without function Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:00 +0200
    RE: [PATCH v3 4/6] perf probe: Fix error reported when offset  without function 平松雅巳 / HIRAMATU,MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2015-08-26 14:30 +0200
    [tip:perf/core] perf probe:   Fix error reported when offset without function tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-28 08:50 +0200
  [PATCH v3 3/6] perf probe: Fix list result when address is zero Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:10 +0200
    RE: [PATCH v3 3/6] perf probe: Fix list result when address is zero 平松雅巳 / HIRAMATU,MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2015-08-26 14:20 +0200
    [tip:perf/core] perf probe: Fix list result when address is zero tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-28 08:50 +0200
  Re: [PATCH v3 2/6] perf probe: Fix list result when neither dwarf  nor map can't find symbol "Wangnan (F)" <wangnan0@huawei.com> - 2015-08-26 13:10 +0200
  [PATCH v3 2/6] perf probe: Fix list result when neither dwarf nor map can't find symbol Wang Nan <wangnan0@huawei.com> - 2015-08-26 13:10 +0200

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