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Date: Sat, 13 Jun 2015 10:16:15 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
CC: Naohiro Aota <naota@...sp.net>,
Peter Zijlstra <peterz@...radead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
David Ahern <dsahern@...il.com>, namhyung@...nel.org,
Jiri Olsa <jolsa@...hat.com>, Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH perf/core 3/4] [BUGFIX] perf probe: Check non-probe-able
symbols when using symbol map
On 2015/06/13 4:17, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jun 12, 2015 at 02:08:27PM +0900, Masami Hiramatsu escreveu:
>> Fix to check both of non-exist symbols and kprobe blacklist symbols at
>> symbol-map based converting too.
>>
>> E.g. without this fix, perf-probe failes to write the event.
>> ----
>> # perf probe vfs_caches_init_early
>> Added new event:
>> Failed to write event: Invalid argument
>> Error: Failed to add events.
>> ----
>>
>> This fixes it to catch the error before adding probes.
>> ----
>> # perf probe vfs_caches_init_early
>> vfs_caches_init_early is out of .text, skip it.
>> Error: Failed to add events.
>> ----
>
> Not applying to my perf/core branch, maybe it needs the first patch in
> this series, that is not applied so far?
Yes, I'll resend the series without 2/4, with fixing previous bug...
Thank you!!
>
> - Arnaldo
>
>> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
>> ---
>> tools/perf/util/probe-event.c | 113 ++++++++++++++++++++++++++---------------
>> 1 file changed, 71 insertions(+), 42 deletions(-)
>>
>> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
>> index 7aa3efe..aa2479e 100644
>> --- a/tools/perf/util/probe-event.c
>> +++ b/tools/perf/util/probe-event.c
>> @@ -246,6 +246,20 @@ static void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs)
>> clear_probe_trace_event(tevs + i);
>> }
>>
>> +static bool kprobe_blacklist__listed(unsigned long address);
>> +static bool kprobe_warn_out_range(const char *symbol, unsigned long address)
>> +{
>> + /* Get the address of _etext for checking non-probable text symbol */
>> + if (kernel_get_symbol_address_by_name("_etext", false) < 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);
>> + else
>> + return false;
>> +
>> + return true;
>> +}
>> +
>> #ifdef HAVE_DWARF_SUPPORT
>>
>> static int kernel_get_module_dso(const char *module, struct dso **pdso)
>> @@ -559,7 +573,6 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs,
>> bool uprobe)
>> {
>> struct ref_reloc_sym *reloc_sym;
>> - u64 etext_addr;
>> char *tmp;
>> int i, skipped = 0;
>>
>> @@ -575,31 +588,28 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs,
>> pr_warning("Relocated base symbol is not found!\n");
>> return -EINVAL;
>> }
>> - /* Get the address of _etext for checking non-probable text symbol */
>> - etext_addr = kernel_get_symbol_address_by_name("_etext", false);
>>
>> for (i = 0; i < ntevs; i++) {
>> - if (tevs[i].point.address && !tevs[i].point.retprobe) {
>> - /* If we found a wrong one, mark it by NULL symbol */
>> - if (etext_addr < tevs[i].point.address) {
>> - pr_warning("%s+%lu is out of .text, skip it.\n",
>> - tevs[i].point.symbol, tevs[i].point.offset);
>> - tmp = NULL;
>> - skipped++;
>> - } else {
>> - tmp = strdup(reloc_sym->name);
>> - if (!tmp)
>> - return -ENOMEM;
>> - }
>> - /* If we have no realname, use symbol for it */
>> - if (!tevs[i].point.realname)
>> - tevs[i].point.realname = tevs[i].point.symbol;
>> - else
>> - free(tevs[i].point.symbol);
>> - tevs[i].point.symbol = tmp;
>> - tevs[i].point.offset = tevs[i].point.address -
>> - reloc_sym->unrelocated_addr;
>> + if (!tevs[i].point.address || tevs[i].point.retprobe)
>> + continue;
>> + /* If we found a wrong one, mark it by NULL symbol */
>> + if (kprobe_warn_out_range(tevs[i].point.symbol,
>> + tevs[i].point.address)) {
>> + tmp = NULL;
>> + skipped++;
>> + } else {
>> + tmp = strdup(reloc_sym->name);
>> + if (!tmp)
>> + return -ENOMEM;
>> }
>> + /* If we have no realname, use symbol for it */
>> + if (!tevs[i].point.realname)
>> + tevs[i].point.realname = tevs[i].point.symbol;
>> + else
>> + free(tevs[i].point.symbol);
>> + tevs[i].point.symbol = tmp;
>> + tevs[i].point.offset = tevs[i].point.address -
>> + reloc_sym->unrelocated_addr;
>> }
>> return skipped;
>> }
>> @@ -2126,6 +2136,27 @@ kprobe_blacklist__find_by_address(struct list_head *blacklist,
>> return NULL;
>> }
>>
>> +static LIST_HEAD(kprobe_blacklist);
>> +
>> +static void kprobe_blacklist__init(void)
>> +{
>> + if (!list_empty(&kprobe_blacklist))
>> + return;
>> +
>> + if (kprobe_blacklist__load(&kprobe_blacklist) < 0)
>> + pr_debug("No kprobe blacklist support, ignored\n");
>> +}
>> +
>> +static void kprobe_blacklist__release(void)
>> +{
>> + kprobe_blacklist__delete(&kprobe_blacklist);
>> +}
>> +
>> +static bool kprobe_blacklist__listed(unsigned long address)
>> +{
>> + return !!kprobe_blacklist__find_by_address(&kprobe_blacklist, address);
>> +}
>> +
>> static int perf_probe_event__sprintf(struct perf_probe_event *pev,
>> const char *module,
>> struct strbuf *result)
>> @@ -2409,8 +2440,6 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
>> char buf[64];
>> const char *event, *group;
>> struct strlist *namelist;
>> - LIST_HEAD(blacklist);
>> - struct kprobe_blacklist_node *node;
>> bool safename;
>>
>> if (pev->uprobes)
>> @@ -2430,28 +2459,15 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
>> ret = -ENOMEM;
>> goto close_out;
>> }
>> - /* Get kprobe blacklist if exists */
>> - if (!pev->uprobes) {
>> - ret = kprobe_blacklist__load(&blacklist);
>> - if (ret < 0)
>> - pr_debug("No kprobe blacklist support, ignored\n");
>> - }
>>
>> safename = (pev->point.function && !strisglob(pev->point.function));
>> ret = 0;
>> pr_info("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
>> for (i = 0; i < ntevs; i++) {
>> tev = &tevs[i];
>> - /* Skip if the symbol is out of .text (marked previously) */
>> + /* Skip if the symbol is out of .text or blacklisted */
>> if (!tev->point.symbol)
>> continue;
>> - /* Ensure that the address is NOT blacklisted */
>> - node = kprobe_blacklist__find_by_address(&blacklist,
>> - tev->point.address);
>> - if (node) {
>> - pr_warning("Warning: Skipped probing on blacklisted function: %s\n", node->symbol);
>> - continue;
>> - }
>>
>> if (pev->event)
>> event = pev->event;
>> @@ -2513,7 +2529,6 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
>> tev->event);
>> }
>>
>> - kprobe_blacklist__delete(&blacklist);
>> strlist__delete(namelist);
>> close_out:
>> close(fd);
>> @@ -2563,7 +2578,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>> struct perf_probe_point *pp = &pev->point;
>> struct probe_trace_point *tp;
>> int num_matched_functions;
>> - int ret, i, j;
>> + int ret, i, j, skipped = 0;
>>
>> map = get_target_map(pev->target, pev->uprobes);
>> if (!map) {
>> @@ -2631,7 +2646,12 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>> }
>> /* Add one probe point */
>> tp->address = map->unmap_ip(map, sym->start) + pp->offset;
>> - if (reloc_sym) {
>> + /* If we found a wrong one, mark it by NULL symbol */
>> + if (!pev->uprobes &&
>> + kprobe_warn_out_range(sym->name, tp->address)) {
>> + tp->symbol = NULL; /* Skip it */
>> + skipped++;
>> + } else if (reloc_sym) {
>> tp->symbol = strdup_or_goto(reloc_sym->name, nomem_out);
>> tp->offset = tp->address - reloc_sym->addr;
>> } else {
>> @@ -2667,6 +2687,10 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>> }
>> arch__fix_tev_from_maps(pev, tev, map);
>> }
>> + if (ret == skipped) {
>> + ret = -ENOENT;
>> + goto err_out;
>> + }
>>
>> out:
>> put_target_map(map, pev->uprobes);
>> @@ -2737,6 +2761,9 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
>> /* Loop 1: convert all events */
>> for (i = 0; i < npevs; i++) {
>> pkgs[i].pev = &pevs[i];
>> + /* Init kprobe blacklist if needed */
>> + if (!pkgs[i].pev->uprobes)
>> + kprobe_blacklist__init();
>> /* Convert with or without debuginfo */
>> ret = convert_to_probe_trace_events(pkgs[i].pev,
>> &pkgs[i].tevs);
>> @@ -2744,6 +2771,8 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
>> goto end;
>> pkgs[i].ntevs = ret;
>> }
>> + /* This just release blacklist only if allocated */
>> + kprobe_blacklist__release();
>>
>> /* Loop 2: add all events */
>> for (i = 0; i < npevs; i++) {
>>
>
--
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@...achi.com
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