From: Masami Hiramatsu mhiramat@kernel.org
commit 80526491c2ca6abc028c0f0dbb0707a1f35fb18a upstream.
Fix to check kprobe blacklist address correctly with relocated address by adjusting debuginfo address.
Since the address in the debuginfo is same as objdump, it is different from relocated kernel address with KASLR. Thus, 'perf probe' always misses to catch the blacklisted addresses.
Without this patch, 'perf probe' can not detect the blacklist addresses on a KASLR enabled kernel.
# perf probe kprobe_dispatcher Failed to write event: Invalid argument Error: Failed to add events. #
With this patch, it correctly shows the error message.
# perf probe kprobe_dispatcher kprobe_dispatcher is blacklisted function, skip it. Probe point 'kprobe_dispatcher' not found. Error: Failed to add events. #
Fixes: 9aaf5a5f479b ("perf probe: Check kprobes blacklist when adding new events") Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/158763966411.30755.5882376357738273695.stgit@dev... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- tools/perf/util/probe-event.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-)
--- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -102,7 +102,7 @@ void exit_probe_symbol_maps(void) symbol__exit(); }
-static struct ref_reloc_sym *kernel_get_ref_reloc_sym(void) +static struct ref_reloc_sym *kernel_get_ref_reloc_sym(struct map **pmap) { /* kmap->ref_reloc_sym should be set if host_machine is initialized */ struct kmap *kmap; @@ -114,6 +114,10 @@ static struct ref_reloc_sym *kernel_get_ kmap = map__kmap(map); if (!kmap) return NULL; + + if (pmap) + *pmap = map; + return kmap->ref_reloc_sym; }
@@ -125,7 +129,7 @@ static int kernel_get_symbol_address_by_ struct map *map;
/* ref_reloc_sym is just a label. Need a special fix*/ - reloc_sym = kernel_get_ref_reloc_sym(); + reloc_sym = kernel_get_ref_reloc_sym(NULL); if (reloc_sym && strcmp(name, reloc_sym->name) == 0) *addr = (reloc) ? reloc_sym->addr : reloc_sym->unrelocated_addr; else { @@ -745,6 +749,7 @@ post_process_kernel_probe_trace_events(s int ntevs) { struct ref_reloc_sym *reloc_sym; + struct map *map; char *tmp; int i, skipped = 0;
@@ -753,7 +758,7 @@ post_process_kernel_probe_trace_events(s return post_process_offline_probe_trace_events(tevs, ntevs, symbol_conf.vmlinux_name);
- reloc_sym = kernel_get_ref_reloc_sym(); + reloc_sym = kernel_get_ref_reloc_sym(&map); if (!reloc_sym) { pr_warning("Relocated base symbol is not found!\n"); return -EINVAL; @@ -764,9 +769,13 @@ post_process_kernel_probe_trace_events(s continue; if (tevs[i].point.retprobe && !kretprobe_offset_is_supported()) continue; - /* If we found a wrong one, mark it by NULL symbol */ + /* + * If we found a wrong one, mark it by NULL symbol. + * Since addresses in debuginfo is same as objdump, we need + * to convert it to addresses on memory. + */ if (kprobe_warn_out_range(tevs[i].point.symbol, - tevs[i].point.address)) { + map__objdump_2mem(map, tevs[i].point.address))) { tmp = NULL; skipped++; } else { @@ -2922,7 +2931,7 @@ static int find_probe_trace_events_from_ /* Note that the symbols in the kmodule are not relocated */ if (!pev->uprobes && !pev->target && (!pp->retprobe || kretprobe_offset_is_supported())) { - reloc_sym = kernel_get_ref_reloc_sym(); + reloc_sym = kernel_get_ref_reloc_sym(NULL); if (!reloc_sym) { pr_warning("Relocated base symbol is not found!\n"); ret = -EINVAL;