Messages in this thread | | | Date | Thu, 16 Jul 2020 18:47:14 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v2 1/4] perf-probe: Avoid setting probes on same address on same event |
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Em Fri, Jul 10, 2020 at 10:11:04PM +0900, Masami Hiramatsu escreveu: > There is a case that the several same-name symbols points > same address. In that case, perf probe returns an error. > > E.g. > > perf probe -x /lib64/libc-2.30.so -v -a "memcpy arg1=%di" > probe-definition(0): memcpy arg1=%di > symbol:memcpy file:(null) line:0 offset:0 return:0 lazy:(null) > parsing arg: arg1=%di into name:arg1 %di > 1 arguments > symbol:setjmp file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:longjmp file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:longjmp_target file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:lll_lock_wait_private file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_arena_max file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_arena_test file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_tunable_tcache_max_bytes file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_tunable_tcache_count file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_tunable_tcache_unsorted_limit file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_trim_threshold file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_top_pad file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_mmap_threshold file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_mmap_max file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_perturb file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_mxfast file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_heap_new file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_arena_reuse_free_list file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_arena_reuse file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_arena_reuse_wait file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_arena_new file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_arena_retry file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_sbrk_less file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_heap_free file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_heap_less file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_tcache_double_free file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_heap_more file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_sbrk_more file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_malloc_retry file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_memalign_retry file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt_free_dyn_thresholds file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_realloc_retry file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_calloc_retry file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:memory_mallopt file:(null) line:0 offset:0 return:0 lazy:(null) > Open Debuginfo file: /usr/lib/debug/usr/lib64/libc-2.30.so.debug > Try to find probe point from debuginfo. > Opening /sys/kernel/debug/tracing//README write=0 > Failed to find the location of the '%di' variable at this address. > Perhaps it has been optimized out. > Use -V with the --range option to show '%di' location range. > An error occurred in debuginfo analysis (-2). > Trying to use symbols. > Opening /sys/kernel/debug/tracing//uprobe_events write=1 > Writing event: p:probe_libc/memcpy /usr/lib64/libc-2.30.so:0x914c0 arg1=%di > Writing event: p:probe_libc/memcpy /usr/lib64/libc-2.30.so:0x914c0 arg1=%di > Failed to write event: File exists > Error: Failed to add events. Reason: File exists (Code: -17) > > You can see the perf tried to write completely same probe definition > twice, which caused an error. > > To fix this issue, check the symbol list and drop duplicated > symbols (which has same symbol name and address) from it. > > With this patch; > > # perf probe -x /lib64/libc-2.30.so -a "memcpy arg1=%di" > Failed to find the location of the '%di' variable at this address. > Perhaps it has been optimized out. > Use -V with the --range option to show '%di' location range. > Added new events: > probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di) > probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di) > > You can now use it in all perf tools, such as: > > perf record -e probe_libc:memcpy -aR sleep 1 > > > Reported-by: Andi Kleen <andi@firstfloor.org> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > --- > Changes in V2 > - Change "find" word to "Found". > --- > tools/perf/util/probe-event.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > index df713a5d1e26..8cd1224e5f4c 100644 > --- a/tools/perf/util/probe-event.c > +++ b/tools/perf/util/probe-event.c > @@ -2968,6 +2968,16 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev, > for (j = 0; j < num_matched_functions; j++) { > sym = syms[j]; > > + /* There can be duplicated symbols in the map */ > + for (i = 0; i < j; i++) > + if (sym->start == syms[i]->start) { > + pr_debug("Found duplicated symbol %s @ %lx\n", > + sym->name, sym->start); > + break; > + }
Breaks 32-bit builds with:
CC /tmp/build/perf/util/demangle-java.o In file included from util/probe-event.c:27: util/probe-event.c: In function 'find_probe_trace_events_from_map': util/probe-event.c:2978:14: error: format '%lx' expects argument of type 'long unsigned int', but argument 5 has type 'u64' {aka 'long long unsigned int'} [-Werror=format=] pr_debug("Found duplicated symbol %s @ %lx\n", ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ util/debug.h:17:21: note: in definition of macro 'pr_fmt' #define pr_fmt(fmt) fmt ^~~ util/probe-event.c:2978:5: note: in expansion of macro 'pr_debug' pr_debug("Found duplicated symbol %s @ %lx\n", ^~~~~~~~ CC /tmp/build/perf/util/demangle-rust.o
I'll change this to use PRIx64.
- Arnaldo
> + if (i != j) > + continue; > + > tev = (*tevs) + ret; > tp = &tev->point; > if (ret == num_matched_functions) { >
--
- Arnaldo
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