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FAILED: patch "[PATCH] perf probe: Fix to check blacklist address correctly" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Jun 19, 2020

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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 80526491c2ca6abc028c0f0dbb0707a1f35fb18a Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <[email protected]>
Date: Thu, 23 Apr 2020 20:01:04 +0900
Subject: [PATCH] perf probe: Fix to check blacklist address correctly

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 <[email protected]>
Tested-by Arnaldo Carvalho de Melo <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Namhyung Kim <[email protected]>
Cc [email protected]
Link http://lore.kernel.org/lkml/158763966411.30755.5882376357738273695.stgit@devnote2 open here
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
tools/perf/util/probe-event.c +15 -6
index c6bcf5709564..63d936f6e993 100644
@@ -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_ref_reloc_sym(void)
 	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_name(const char *name, u64 *addr,
 	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(struct probe_trace_event *tevs,
 				       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(struct probe_trace_event *tevs,
 		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(struct probe_trace_event *tevs,
 			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 {

@@ -2935,7 +2944,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	/* 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;