Messages in this thread Patch in this message | | | From | He Kuang <> | Subject | [PATCH v2] perf probe: Fix failure to probe events on arm | Date | Thu, 18 Jun 2015 02:49:10 +0000 |
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Fix failure to probe events on arm, problem is introduced by commit 5a51fcd1f30c ("perf probe: Skip kernel symbols which is out of .text"). For some architectures, label '_etext' is not in the .text section(in .notes section for arm/arm64). Label out of .text section is not loaded as symbols and we got a zero value when look up its address, which causes all events be wrongly skiped.
This patch skip checking text address range when failed to get the address of '_etext' and fixes the problem.
Problem can be reproduced on arm as following:
# perf probe --add='generic_perform_write' generic_perform_write+0 is out of .text, skip it. Probe point 'generic_perform_write' not found. Error: Failed to add events.
After this patch:
# perf probe --add='generic_perform_write' Added new event: probe:generic_perform_write (on generic_perform_write)
You can now use it in all perf tools, such as:
perf record -e probe:generic_perform_write -aR sleep 1
Signed-off-by: He Kuang <hekuang@huawei.com> --- tools/perf/util/probe-event.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 076527b..381f23a 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -249,8 +249,12 @@ static void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs) static bool kprobe_blacklist__listed(unsigned long address); static bool kprobe_warn_out_range(const char *symbol, unsigned long address) { + u64 etext_addr; + /* Get the address of _etext for checking non-probable text symbol */ - if (kernel_get_symbol_address_by_name("_etext", false) < address) + etext_addr = kernel_get_symbol_address_by_name("_etext", false); + + if (etext_addr != 0 && etext_addr < address) pr_warning("%s is out of .text, skip it.\n", symbol); else if (kprobe_blacklist__listed(address)) pr_warning("%s is blacklisted function, skip it.\n", symbol); -- 1.8.5.2
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