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由 Masami Hiramatsu 提交于
Fix perf probe to probe on some symbols which have some optimzation suffixes, e.g. ".part", ".isra", and ".constprop". To fix this issue, instead of using the DIE name, perf probe uses the symbol name found by dwfl_module_addrsym(). This also involves a perf probe --vars operation update which now shows the symbol name instead of the DIE name. Without this patch, putting a probe on an inlined function which was compiled with a suffixed symbol will fail like this: $ perf probe -v getname_flags probe-definition(0): getname_flags symbol:getname_flags file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Looking at the vmlinux_path (6 entries long) Using /lib/modules/3.11.0+/build/vmlinux for symbols found inline addr: 0xffffffff8119bb70 Probe point found: getname_flags+0 found inline addr: 0xffffffff8119bcb6 Probe point found: getname+6 found inline addr: 0xffffffff811a06a6 Probe point found: user_path_at_empty+6 find 3 probe_trace_events. Opening /sys/kernel/debug//tracing/kprobe_events write=1 Added new events: Writing event: p:probe/getname_flags getname_flags+0 Failed to write event: No such file or directory Error: Failed to add events. (-1) Because the debuginfo knows only the original (non suffix) symbol name, it uses the original symbol for probe address but the kernel (kallsyms) knows only suffixed symbol. Then, the kernel rejects that original symbol. This patch uses dwfl_module_addrsym() to get the correct (suffixed) symbol from symtab when a probe point is found. Reported-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20130925131616.31632.46658.stgit@udc4-manage.rcp.hitachi.co.jpSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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