From: Arnaldo Carvalho de Melo acme@redhat.com
[ Upstream commit 249d98e567e25dd03e015e2d31e1b7b9648f34df ]
When setting the "dwarf" unwinder for a specific event and not specifying the max-stack, the attr.sample_max_stack ended up using an uninitialized callchain_param.max_stack, fix it by using designated initializers for that callchain_param variable, zeroing all non explicitely initialized struct members.
Here is what happened:
# perf trace -vv --no-syscalls --max-stack 4 -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1 callchain: type DWARF callchain: stack dump size 8192 perf_event_attr: type 2 size 112 config 0x730 { sample_period, sample_freq } 1 sample_type IP|TID|TIME|ADDR|CALLCHAIN|CPU|PERIOD|RAW|REGS_USER|STACK_USER|DATA_SRC exclude_callchain_user 1 { wakeup_events, wakeup_watermark } 1 sample_regs_user 0xff0fff sample_stack_user 8192 sample_max_stack 50656 sys_perf_event_open failed, error -75 Value too large for defined data type # perf trace -vv --no-syscalls --max-stack 4 -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1 callchain: type DWARF callchain: stack dump size 8192 perf_event_attr: type 2 size 112 config 0x730 sample_type IP|TID|TIME|ADDR|CALLCHAIN|CPU|PERIOD|RAW|REGS_USER|STACK_USER|DATA_SRC exclude_callchain_user 1 sample_regs_user 0xff0fff sample_stack_user 8192 sample_max_stack 30448 sys_perf_event_open failed, error -75 Value too large for defined data type #
Now the attr.sample_max_stack is set to zero and the above works as expected:
# perf trace --no-syscalls --max-stack 4 -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1 PING ::1(::1) 56 data bytes 64 bytes from ::1: icmp_seq=1 ttl=64 time=0.072 ms
--- ::1 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 0.072/0.072/0.072/0.000 ms 0.000 probe_libc:inet_pton:(7feb7a998350)) __inet_pton (inlined) gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so) __GI_getaddrinfo (inlined) [0xffffaa39b6108f3f] (/usr/bin/ping) #
Cc: Adrian Hunter adrian.hunter@intel.com Cc: David Ahern dsahern@gmail.com Cc: Hendrick Brueckner brueckner@linux.vnet.ibm.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: Thomas Richter tmricht@linux.vnet.ibm.com Cc: Wang Nan wangnan0@huawei.com Link: https://lkml.kernel.org/n/tip-is9tramondqa9jlxxsgcm9iz@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- tools/perf/util/evsel.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 1c1291afd6a6..4b52c76fb2a8 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -694,14 +694,14 @@ static void apply_config_terms(struct perf_evsel *evsel, struct perf_evsel_config_term *term; struct list_head *config_terms = &evsel->config_terms; struct perf_event_attr *attr = &evsel->attr; - struct callchain_param param; + /* callgraph default */ + struct callchain_param param = { + .record_mode = callchain_param.record_mode, + }; u32 dump_size = 0; int max_stack = 0; const char *callgraph_buf = NULL;
- /* callgraph default */ - param.record_mode = callchain_param.record_mode; - list_for_each_entry(term, config_terms, list) { switch (term->type) { case PERF_EVSEL__CONFIG_TERM_PERIOD: