* [PATCH] perf tools: Fix segfault for kernel.kptr_restrict=2
@ 2017-06-26 9:51 Jiri Olsa
2017-06-27 7:21 ` [tip:perf/urgent] perf machine: " tip-bot for Jiri Olsa
0 siblings, 1 reply; 2+ messages in thread
From: Jiri Olsa @ 2017-06-26 9:51 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: lkml, Ingo Molnar, Peter Zijlstra, Namhyung Kim, David Ahern,
Michael Petlan
Michael reported the segfault when kernel.kptr_restrict=2 is set.
$ perf record ls
...
perf: Segmentation fault
Obtained 16 stack frames.
./perf(dump_stack+0x2d) [0x5068df]
./perf(sighandler_dump_stack+0x2d) [0x5069bf]
./perf() [0x43e47b]
/lib64/libc.so.6(+0x3594f) [0x7f762004794f]
/lib64/libc.so.6(strlen+0x26) [0x7f762009ef86]
/lib64/libc.so.6(__strdup+0xd) [0x7f762009ecbd]
./perf(maps__set_kallsyms_ref_reloc_sym+0x4d) [0x51590f]
./perf(machine__create_kernel_maps+0x136) [0x50a7de]
./perf(perf_session__create_kernel_maps+0x2c) [0x510a81]
./perf(perf_session__new+0x13d) [0x510e23]
./perf() [0x43fd61]
./perf(cmd_record+0x704) [0x441823]
./perf() [0x4bc1a0]
./perf() [0x4bc40d]
./perf() [0x4bc55f]
./perf(main+0x2d5) [0x4bc939]
Segmentation fault (core dumped)
The reason is that with kernel.kptr_restrict=2, we don't get
the symbol from machine__get_running_kernel_start, which we
want to use in maps__set_kallsyms_ref_reloc_sym and we crash.
Check the symbol name value before calling
maps__set_kallsyms_ref_reloc_sym and succeed without
ref_reloc_sym being set. It's safe because we check
its existence before we use it.
Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/util/machine.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index d7f31cb0a4cb..5de2b86b9880 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1209,10 +1209,12 @@ int machine__create_kernel_maps(struct machine *machine)
*/
map_groups__fixup_end(&machine->kmaps);
- if (machine__get_running_kernel_start(machine, &name, &addr)) {
- } else if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
- machine__destroy_kernel_maps(machine);
- return -1;
+ if (!machine__get_running_kernel_start(machine, &name, &addr)) {
+ if (name &&
+ maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
+ machine__destroy_kernel_maps(machine);
+ return -1;
+ }
}
return 0;
--
2.9.4
^ permalink raw reply related [flat|nested] 2+ messages in thread* [tip:perf/urgent] perf machine: Fix segfault for kernel.kptr_restrict=2
2017-06-26 9:51 [PATCH] perf tools: Fix segfault for kernel.kptr_restrict=2 Jiri Olsa
@ 2017-06-27 7:21 ` tip-bot for Jiri Olsa
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Jiri Olsa @ 2017-06-27 7:21 UTC (permalink / raw)
To: linux-tip-commits
Cc: hpa, jolsa, tglx, linux-kernel, a.p.zijlstra, mingo, namhyung,
dsahern, acme, mpetlan
Commit-ID: 3f938ee2f6c4fff8d95b24636a0964b5a93cf547
Gitweb: http://git.kernel.org/tip/3f938ee2f6c4fff8d95b24636a0964b5a93cf547
Author: Jiri Olsa <jolsa@kernel.org>
AuthorDate: Mon, 26 Jun 2017 11:51:53 +0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 26 Jun 2017 11:52:37 -0300
perf machine: Fix segfault for kernel.kptr_restrict=2
Michael reported the segfault when kernel.kptr_restrict=2 is set.
$ perf record ls
...
perf: Segmentation fault
Obtained 16 stack frames.
./perf(dump_stack+0x2d) [0x5068df]
./perf(sighandler_dump_stack+0x2d) [0x5069bf]
./perf() [0x43e47b]
/lib64/libc.so.6(+0x3594f) [0x7f762004794f]
/lib64/libc.so.6(strlen+0x26) [0x7f762009ef86]
/lib64/libc.so.6(__strdup+0xd) [0x7f762009ecbd]
./perf(maps__set_kallsyms_ref_reloc_sym+0x4d) [0x51590f]
./perf(machine__create_kernel_maps+0x136) [0x50a7de]
./perf(perf_session__create_kernel_maps+0x2c) [0x510a81]
./perf(perf_session__new+0x13d) [0x510e23]
./perf() [0x43fd61]
./perf(cmd_record+0x704) [0x441823]
./perf() [0x4bc1a0]
./perf() [0x4bc40d]
./perf() [0x4bc55f]
./perf(main+0x2d5) [0x4bc939]
Segmentation fault (core dumped)
The reason is that with kernel.kptr_restrict=2, we don't get
the symbol from machine__get_running_kernel_start, which we
want to use in maps__set_kallsyms_ref_reloc_sym and we crash.
Check the symbol name value before calling
maps__set_kallsyms_ref_reloc_sym() and succeed without ref_reloc_sym
being set. It's safe because we check its existence before we use it.
Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170626095153.553-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/machine.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index d7f31cb..5de2b86 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1209,10 +1209,12 @@ int machine__create_kernel_maps(struct machine *machine)
*/
map_groups__fixup_end(&machine->kmaps);
- if (machine__get_running_kernel_start(machine, &name, &addr)) {
- } else if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
- machine__destroy_kernel_maps(machine);
- return -1;
+ if (!machine__get_running_kernel_start(machine, &name, &addr)) {
+ if (name &&
+ maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
+ machine__destroy_kernel_maps(machine);
+ return -1;
+ }
}
return 0;
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2017-06-27 7:21 ` [tip:perf/urgent] perf machine: " tip-bot for Jiri Olsa
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