Messages in this thread | | | Subject | Re: [PATCH 2/2] perf tools: Fix hybrid config terms list corruption | From | Adrian Hunter <> | Date | Sat, 11 Sep 2021 09:23:06 +0300 |
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On 10/09/21 10:32 pm, Jiri Olsa wrote: > On Thu, Sep 09, 2021 at 03:55:08PM +0300, Adrian Hunter wrote: >> A config terms list was spliced twice, resulting in a never-ending loop >> when the list was traversed. Fix by using list_splice_init() and copying >> and freeing the lists as necessary. >> >> This patch also depends on patch "perf tools: Factor out >> copy_config_terms() and free_config_terms()" >> >> Example on ADL: >> >> Before: >> >> # perf record -e '{intel_pt//,cycles/aux-sample-size=4096/pp}' uname & >> # jobs >> [1]+ Running perf record -e "{intel_pt//,cycles/aux-sample-size=4096/pp}" uname >> # perf top -E 10 >> PerfTop: 4071 irqs/sec kernel: 6.9% exact: 100.0% lost: 0/0 drop: 0/0 [4000Hz cycles], (all, 24 CPUs) >> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- >> >> 97.60% perf [.] __evsel__get_config_term >> 0.25% [kernel] [k] kallsyms_expand_symbol.constprop.13 >> 0.24% perf [.] kallsyms__parse >> 0.15% [kernel] [k] _raw_spin_lock >> 0.14% [kernel] [k] number >> 0.13% [kernel] [k] advance_transaction >> 0.08% [kernel] [k] format_decode >> 0.08% perf [.] map__process_kallsym_symbol >> 0.08% perf [.] rb_insert_color >> 0.08% [kernel] [k] vsnprintf >> exiting. >> # kill %1 >> >> After: >> >> # perf record -e '{intel_pt//,cycles/aux-sample-size=4096/pp}' uname & >> Linux >> [ perf record: Woken up 1 times to write data ] >> [ perf record: Captured and wrote 0.060 MB perf.data ] >> # perf script | head >> perf-exec 604 [001] 1827.312293: psb: psb offs: 0 ffffffffb8415e87 pt_config_start+0x37 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb856a3bd event_sched_in.isra.133+0xfd ([kernel.kallsyms]) => ffffffffb856a9a0 perf_pmu_nop_void+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb856b10e merge_sched_in+0x26e ([kernel.kallsyms]) => ffffffffb856a2c0 event_sched_in.isra.133+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb856a45d event_sched_in.isra.133+0x19d ([kernel.kallsyms]) => ffffffffb8568b80 perf_event_set_state.part.61+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb8568b86 perf_event_set_state.part.61+0x6 ([kernel.kallsyms]) => ffffffffb85662a0 perf_event_update_time+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb856a35c event_sched_in.isra.133+0x9c ([kernel.kallsyms]) => ffffffffb8567610 perf_log_itrace_start+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb856a377 event_sched_in.isra.133+0xb7 ([kernel.kallsyms]) => ffffffffb8403b40 x86_pmu_add+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb8403b86 x86_pmu_add+0x46 ([kernel.kallsyms]) => ffffffffb8403940 collect_events+0x0 ([kernel.kallsyms]) >> perf-exec 604 1827.312293: 1 branches: ffffffffb8403a7b collect_events+0x13b ([kernel.kallsyms]) => ffffffffb8402cd0 collect_event+0x0 ([kernel.kallsyms]) >> >> Fixes: 94da591b1c7913 ("perf parse-events: Create two hybrid raw events") >> Fixes: 9cbfa2f64c04d9 ("perf parse-events: Create two hybrid hardware events") >> Fixes: 30def61f64bac5 ("perf parse-events: Create two hybrid cache events") >> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> >> --- >> tools/perf/util/parse-events-hybrid.c | 18 +++++++++++++++--- >> tools/perf/util/parse-events.c | 18 ++++++++++++------ >> 2 files changed, 27 insertions(+), 9 deletions(-) >> >> diff --git a/tools/perf/util/parse-events-hybrid.c b/tools/perf/util/parse-events-hybrid.c >> index 10160ab126f9..b234d95fb10a 100644 >> --- a/tools/perf/util/parse-events-hybrid.c >> +++ b/tools/perf/util/parse-events-hybrid.c >> @@ -76,12 +76,16 @@ static int add_hw_hybrid(struct parse_events_state *parse_state, >> int ret; >> >> perf_pmu__for_each_hybrid_pmu(pmu) { >> + LIST_HEAD(terms); >> + >> if (pmu_cmp(parse_state, pmu)) >> continue; >> >> + copy_config_terms(&terms, config_terms); >> ret = create_event_hybrid(PERF_TYPE_HARDWARE, >> &parse_state->idx, list, attr, name, >> - config_terms, pmu); >> + &terms, pmu); >> + free_config_terms(&terms); > > hm, why is this needed.. there's now list_splice_init &terms within > create_event_hybrid call right? so there should be nothing nothing > to clean
create_event_hybrid() can fail and not consume 'terms'. By using list_splice_init(), free_config_terms() will only free unconsumed terms.
> > same below
That also has the same reasoning.
> >> if (ret) >> return ret; >> } >> @@ -115,11 +119,15 @@ static int add_raw_hybrid(struct parse_events_state *parse_state, >> int ret; >> >> perf_pmu__for_each_hybrid_pmu(pmu) { >> + LIST_HEAD(terms); >> + >> if (pmu_cmp(parse_state, pmu)) >> continue; >> >> + copy_config_terms(&terms, config_terms); >> ret = create_raw_event_hybrid(&parse_state->idx, list, attr, >> - name, config_terms, pmu); >> + name, &terms, pmu); >> + free_config_terms(&terms); >> if (ret) >> return ret; >> } >> @@ -165,11 +173,15 @@ int parse_events__add_cache_hybrid(struct list_head *list, int *idx, >> >> *hybrid = true; >> perf_pmu__for_each_hybrid_pmu(pmu) { >> + LIST_HEAD(terms); >> + >> if (pmu_cmp(parse_state, pmu)) >> continue; >> >> + copy_config_terms(&terms, config_terms); >> ret = create_event_hybrid(PERF_TYPE_HW_CACHE, idx, list, >> - attr, name, config_terms, pmu); >> + attr, name, &terms, pmu); >> + free_config_terms(&terms); >> if (ret) >> return ret; >> } >> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c >> index ded5808798f9..51a2219df601 100644 >> --- a/tools/perf/util/parse-events.c >> +++ b/tools/perf/util/parse-events.c >> @@ -387,7 +387,7 @@ __add_event(struct list_head *list, int *idx, >> evsel->name = strdup(name); >> >> if (config_terms) >> - list_splice(config_terms, &evsel->config_terms); >> + list_splice_init(config_terms, &evsel->config_terms); >> >> if (list) >> list_add_tail(&evsel->core.node, list); >> @@ -535,9 +535,12 @@ int parse_events_add_cache(struct list_head *list, int *idx, >> config_name ? : name, &config_terms, >> &hybrid, parse_state); >> if (hybrid) >> - return ret; >> + goto out_free_terms; >> >> - return add_event(list, idx, &attr, config_name ? : name, &config_terms); >> + ret = add_event(list, idx, &attr, config_name ? : name, &config_terms); >> +out_free_terms: >> + free_config_terms(&config_terms); > > .. apart from this one and below, when coming from 'goto out_free_terms' > we should call free_config_terms > > jirka > >> + return ret; >> } >> >> static void tracepoint_error(struct parse_events_error *e, int err, >> @@ -1457,10 +1460,13 @@ int parse_events_add_numeric(struct parse_events_state *parse_state, >> get_config_name(head_config), >> &config_terms, &hybrid); >> if (hybrid) >> - return ret; >> + goto out_free_terms; >> >> - return add_event(list, &parse_state->idx, &attr, >> - get_config_name(head_config), &config_terms); >> + ret = add_event(list, &parse_state->idx, &attr, >> + get_config_name(head_config), &config_terms); >> +out_free_terms: >> + free_config_terms(&config_terms); >> + return ret; >> } >> >> int parse_events_add_tool(struct parse_events_state *parse_state, >> -- >> 2.17.1 >> >
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