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authorMasami Hiramatsu <mhiramat@kernel.org>2020-04-23 14:01:13 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-05-28 16:03:24 +0300
commit2ae5d0d7d8868df7c05c2013c0b9cddd4d40610e (patch)
tree52bc911d4f53f60619bd074c5c76be9588dbd321 /tools/perf/builtin-probe.c
parent80526491c2ca6abc028c0f0dbb0707a1f35fb18a (diff)
downloadlinux-2ae5d0d7d8868df7c05c2013c0b9cddd4d40610e.tar.xz
perf probe: Check address correctness by map instead of _etext
Since commit 03db8b583d1c ("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: 03db8b583d1c ("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>
Diffstat (limited to 'tools/perf/builtin-probe.c')
0 files changed, 0 insertions, 0 deletions