Messages in this thread | | | Date | Tue, 23 Jun 2015 12:07:33 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v2] perf probe: Fix failure to probe events on arm |
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On 2015/06/18 11:49, He Kuang wrote: > 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
Looks good to me :)
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Thanks!
> > 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); >
-- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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