Messages in this thread Patch in this message | | | Date | Thu, 27 Aug 2015 23:40:56 -0700 | From | tip-bot for Wang Nan <> | Subject | [tip:perf/core] perf probe: Prevent segfault when reading probe point with absolute address |
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Commit-ID: e486367f0101d43a044404ed2fa35aa043b19667 Gitweb: http://git.kernel.org/tip/e486367f0101d43a044404ed2fa35aa043b19667 Author: Wang Nan <wangnan0@huawei.com> AuthorDate: Tue, 25 Aug 2015 13:27:35 +0000 Committer: Arnaldo Carvalho de Melo <acme@redhat.com> CommitDate: Wed, 26 Aug 2015 10:34:11 -0300
perf probe: Prevent segfault when reading probe point with absolute address
'perf probe -l' panic if there is a manually inserted probing point with absolute address. For example:
# echo 'p:probe/abs_ffffffff811e6615 0xffffffff811e6615' > /sys/kernel/debug/tracing/kprobe_events # perf probe -l Segmentation fault (core dumped)
This patch fix this problem by considering the situation that "tp->symbol == NULL" in find_perf_probe_point_from_dwarf() and find_perf_probe_point_from_map().
After this patch:
# perf probe -l probe:abs_ffffffff811e6615 (on SyS_write+5@fs/read_write.c)
And when debug info is missing:
# rm -rf ~/.debug # mv /lib/modules/4.2.0-rc1+/build/vmlinux /lib/modules/4.2.0-rc1+/build/vmlinux.bak # perf probe -l probe:abs_ffffffff811e6615 (on sys_write+5)
Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1440509256-193590-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/probe-event.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index f07374b..6c7e538 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -515,7 +515,7 @@ static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp, if (ret < 0) goto error; addr += stext; - } else { + } else if (tp->symbol) { addr = kernel_get_symbol_address_by_name(tp->symbol, false); if (addr == 0) goto error; @@ -1815,17 +1815,17 @@ static int find_perf_probe_point_from_map(struct probe_trace_point *tp, { struct symbol *sym = NULL; struct map *map; - u64 addr; + u64 addr = tp->address; int ret = -ENOENT; if (!is_kprobe) { map = dso__new_map(tp->module); if (!map) goto out; - addr = tp->address; sym = map__find_symbol(map, addr, NULL); } else { - addr = kernel_get_symbol_address_by_name(tp->symbol, true); + if (tp->symbol) + addr = kernel_get_symbol_address_by_name(tp->symbol, true); if (addr) { addr += tp->offset; sym = __find_kernel_function(addr, &map);
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