Messages in this thread | | | Date | Thu, 26 Nov 2015 11:22:11 +0800 | From | "Wangnan (F)" <> | Subject | Re: [PATCH] perf probe: Adjust dso->long_name for offline module |
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On 2015/11/26 3:35, Arnaldo Carvalho de Melo wrote: > Em Wed, Nov 25, 2015 at 11:30:59AM +0000, Wang Nan escreveu: >> If libelf unable to open debuginfo for an offline module but the ko has >> symtab, something unexpected may happen. >> >> # rm -rf ~/.debug/ >> # mv /usr/lib64/elfutils/libebl_x86_64.so{,.bak} >> # ./perf probe -m /home/wangnan/kmodule/mymodule.ko my_func >> [mymodule] with build id 326ab42550ef3d24944f53c817533728367effeb not found, continuing without symbols >> Failed to find symbol my_func in /home/wangnan/kmodule/mymodule.ko > Understood, since we are giving the path to that module, we can, if its > build-id matches the one for the online module, use it, is that the > case, i.e. do we check, int his scenario, that the build-id matches?
Please see my test result in v2 patch [1]. In symsrc__init() build-id would be checked.
[1] http://lkml.kernel.org/r/1448507949-187812-1-git-send-email-wangnan0@huawei.com
# ./perf probe -m ./mymodule.ko my_func Added new event: probe:my_func (on my_func in /home/wangnan/kmodule/mymodule.ko)
You can now use it in all perf tools, such as:
perf record -e probe:my_func -aR sleep 1
# ./perf probe -d '*' Removed event: probe:my_func # mv ./mymodule.{ko,.bak} # mv ./moduleb.ko mymodule.ko # ./perf probe -m ./mymodule.ko my_func /home/wangnan/kmodule/mymodule.ko with build id 326ab42550ef3d24944f53c817533728367effeb not found, continuing without symbols Failed to find symbol my_func in /home/wangnan/kmodule/mymodule.ko Error: Failed to add events.
# ./perf probe -v -m ./mymodule.ko my_func probe-definition(0): my_func symbol:my_funcfile:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Could not open debuginfo. Try to use symbols. symsrc__init: build id mismatch for /home/wangnan/kmodule/mymodule.ko. /home/wangnan/kmodule/mymodule.ko with build id 326ab42550ef3d24944f53c817533728367effeb not found, continuing without symbols Failed to find symbol my_func in /home/wangnan/kmodule/mymodule.ko Error: Failed to add events. Reason: No such file or directory (Code: -2)
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