Since commit 03db8b583d ("perf tools: Fix
maps__find_symbol_by_name()") introduced map address range check in
maps__find_symbol_by_name(), we can not get "_etext" from kernel map
because _etext is placed on the edge of the kernel .text section (=
kernel map in perf.)
To fix this issue, this checks the address correctness by map address
range information (map->start and map->end) instead of using _etext
address.
This can cause an error if the target inlined function is embedded in
both __init function and normal function.
For exaample, request_resource() is a normal function but also embedded
in __init reserve_setup(). In this case, the probe point in
reserve_setup() must be skipped.
However, without this fix, it failes to setup all probe points:
# ./perf probe -v request_resource
probe-definition(0): request_resource
symbol:request_resource file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
Looking at the vmlinux_path (8 entries long)
Using /usr/lib/debug/lib/modules/5.5.17-200.fc31.x86_64/vmlinux for symbols
Open Debuginfo file: /usr/lib/debug/lib/modules/5.5.17-200.fc31.x86_64/vmlinux
Try to find probe point from debuginfo.
Matched function: request_resource [15e29ad]
found inline addr: 0xffffffff82fbf892
Probe point found: reserve_setup+204
found inline addr: 0xffffffff810e9790
Probe point found: request_resource+0
Found 2 probe_trace_events.
Opening /sys/kernel/debug/tracing//kprobe_events write=1
Opening /sys/kernel/debug/tracing//README write=0
Writing event: p:probe/request_resource _text+33290386
Failed to write event: Invalid argument
Error: Failed to add events. Reason: Invalid argument (Code: -22)
#
With this fix,
# ./perf probe request_resource
reserve_setup is out of .text, skip it.
Added new events:
(null):(null) (on request_resource)
probe:request_resource (on request_resource)
You can now use it in all perf tools, such as:
perf record -e probe:request_resource -aR sleep 1
#
Fixes: 03db8b583d ("perf tools: Fix maps__find_symbol_by_name()")
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/158763967332.30755.4922496724365529088.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2ae5d0d7d8