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Fri, 24 Apr 2026 02:27:44 -0700 (PDT) Received: from [192.168.178.64] ([84.246.200.167]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43fe4cc0d51sm59874331f8f.10.2026.04.24.02.27.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Apr 2026 02:27:43 -0700 (PDT) Message-ID: Date: Fri, 24 Apr 2026 10:27:42 +0100 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] perf sched: Fix crash in sched stats diff due to uninitialized perf_data structure To: Athira Rajeev Cc: linux-perf-users@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, hbathini@linux.vnet.ibm.com, Tejas.Manhas1@ibm.com, Tanushree.Shah@ibm.com, Shivani.Nittor@ibm.com, acme@kernel.org, jolsa@kernel.org, adrian.hunter@intel.com, mpetlan@redhat.com, tmricht@linux.ibm.com, maddy@linux.ibm.com, irogers@google.com, namhyung@kernel.org References: <20260422173545.73144-1-atrajeev@linux.ibm.com> Content-Language: en-US From: James Clark In-Reply-To: <20260422173545.73144-1-atrajeev@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 22/04/2026 18:35, Athira Rajeev wrote: > perf sched stats diff fails sometimes with below logs: > > # perf sched stats record ls > > # perf sched stats diff > *** invalid open64 call: O_CREAT or O_TMPFILE without mode ***: terminated > Aborted (core dumped) > > Also in some runs, perf sched stats tests fails > > ./perf test "perf sched stats tests" > 92: perf sched stats tests : FAILED! > > ==172375== Conditional jump or move depends on uninitialised value(s) > ==172375== at 0x10393BD0: open_file_read (data.c:264) > ==172375== by 0x10393F63: open_file (data.c:317) > ==172375== by 0x10394067: open_file_dup (data.c:334) > ==172375== by 0x103942DF: perf_data__open (data.c:379) > ==172375== by 0x102F7CAF: __perf_session__new (session.c:169) > ==172375== by 0x100B5E63: perf_session__new (session.h:116) > ==172375== by 0x100D5D37: perf_sched__schedstat_diff (builtin-sched.c:4568) > ==172375== by 0x100D7D6F: cmd_sched (builtin-sched.c:5061) > ==172375== by 0x1010231F: run_builtin (perf.c:348) > ==172375== by 0x1010262F: handle_internal_command (perf.c:398) > ==172375== by 0x1010286F: run_argv (perf.c:442) > ==172375== by 0x10102C67: main (perf.c:549) > ==172375== > ==172375== Conditional jump or move depends on uninitialised value(s) > ==172375== at 0x10393D20: open_file_read (data.c:282) > ==172375== by 0x10393F63: open_file (data.c:317) > ==172375== by 0x10394067: open_file_dup (data.c:334) > ==172375== by 0x103942DF: perf_data__open (data.c:379) > ==172375== by 0x102F7CAF: __perf_session__new (session.c:169) > ==172375== by 0x100B5E63: perf_session__new (session.h:116) > ==172375== by 0x100D5D37: perf_sched__schedstat_diff (builtin-sched.c:4568) > ==172375== by 0x100D7D6F: cmd_sched (builtin-sched.c:5061) > ==172375== by 0x1010231F: run_builtin (perf.c:348) > ==172375== by 0x1010262F: handle_internal_command (perf.c:398) > ==172375== by 0x1010286F: run_argv (perf.c:442) > ==172375== by 0x10102C67: main (perf.c:549) > > The valgrind logs and error message from the logs points to > below snippet: > > static int open_file_read(struct perf_data *data) > { > int flags = data->in_place_update ? O_RDWR : O_RDONLY; > struct stat st; > int fd; > > fd = open(data->file.path, flags); > > The "struct perf_data" is defined here : > > static int perf_sched__schedstat_diff(struct perf_sched *sched, > int argc, const char **argv) > { > struct cpu_domain_map **cd_map0 = NULL, **cd_map1 = NULL; > struct list_head cpu_head_ses0, cpu_head_ses1; > struct perf_session *session[2]; > struct perf_data data[2]; > int ret = 0, err = 0; > static const char *defaults[] = { > "perf.data.old", > "perf.data", > }; > > Here due to uninitialized "struct perf_data", the arguments to "open" > is getting wrongly passed sometimes depending on value in stack. > When perf_data__open() function calls open_file_read(),the > "in_place_update" could contain garbage value. > > After initializing "struct perf_data" in perf_sched__schedstat_diff() function, > perf sched stats tests runs without issues in multiple attempts and also > "perf sched stats diff" ran individual without issues. > > for i in {0..20}; do ./perf test "perf sched stats tests"; done > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > 92: perf sched stats tests : Ok > > Signed-off-by: Athira Rajeev > --- > tools/perf/builtin-sched.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c > index 555247568e7a..5d2740099eed 100644 > --- a/tools/perf/builtin-sched.c > +++ b/tools/perf/builtin-sched.c > @@ -4538,7 +4538,7 @@ static int perf_sched__schedstat_diff(struct perf_sched *sched, > struct cpu_domain_map **cd_map0 = NULL, **cd_map1 = NULL; > struct list_head cpu_head_ses0, cpu_head_ses1; > struct perf_session *session[2]; > - struct perf_data data[2]; > + struct perf_data data[2] = { 0 }; > int ret = 0, err = 0; > static const char *defaults[] = { > "perf.data.old", Reviewed-by: James Clark I had a quick look for other instances of the same thing and didn't see any.