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In `get_all_cpu_stats()`, added `assert(!list_empty(head))` to prevent unsafe `list_first_entry()` calls on empty lists, fixed uninitialized variable `ret`, and added `list_is_last` check when iterating domains to prevent out-of-bounds reads during parallel list traversal. 2. In `show_schedstat_data()`, added NULL checks for `cd_map1` and `cd_map2` to gracefully handle invalid or empty data files. 3. Added parallel iteration termination checks using `list_is_last()` in `show_schedstat_data()` for both domain and CPU lists to safely terminate at the end of each list when files contain a different number of CPUs or domains. 4. Added CPU bounds checks (`cs1->cpu >= nr1` and `cs2->cpu >= nr2`) in `show_schedstat_data()` to prevent out-of-bounds reads from `cd_map1` and `cd_map2` when comparing files from machines with different CPU counts. 5. Added NULL checks for `cd_info1` and `cd_info2` to prevent crashes when a CPU has data samples but no corresponding domain info in the header. 6. Added domain bounds checks (`ds1->domain >= cd_info1->nr_domains` and `ds2->domain >= cd_info2->nr_domains`) to prevent out-of-bounds array accesses in the domains array. 7. Added NULL checks for `dinfo1` and `dinfo2` in `show_schedstat_data()` to prevent crashes when a domain has no corresponding domain info. 8. Zero-initialized the `perf_data` array in `perf_sched__schedstat_diff()` to prevent stack garbage from causing `perf_data_file__fd()` to attempt to use a NULL `fptr` when `use_stdio` happened to be non-zero. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers --- v2: Reduce indentation and variable scopes. Hopefully address feedback from James Clark. Previously this patch was part of a large perf script refactor: https://lore.kernel.org/lkml/20260425224951.174663-1-irogers@google.com/ --- tools/perf/builtin-sched.c | 144 +++++++++++++++++++++++++++---------- 1 file changed, 106 insertions(+), 38 deletions(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index 555247568e7a..e67241415255 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -4170,40 +4170,40 @@ static void summarize_schedstat_domain(struct schedstat_domain *summary_domain, */ static int get_all_cpu_stats(struct list_head *head) { - struct schedstat_cpu *cptr = list_first_entry(head, struct schedstat_cpu, cpu_list); - struct schedstat_cpu *summary_head = NULL; - struct perf_record_schedstat_domain *ds; - struct perf_record_schedstat_cpu *cs; - struct schedstat_domain *dptr, *tdptr; + struct schedstat_cpu *cptr, *summary_head; + struct schedstat_domain *dptr; bool is_last = false; int cnt = 1; - int ret = 0; - if (cptr) { - summary_head = zalloc(sizeof(*summary_head)); - if (!summary_head) - return -ENOMEM; + assert(!list_empty(head)); + cptr = list_first_entry(head, struct schedstat_cpu, cpu_list); - summary_head->cpu_data = zalloc(sizeof(*cs)); - memcpy(summary_head->cpu_data, cptr->cpu_data, sizeof(*cs)); + summary_head = zalloc(sizeof(*summary_head)); + if (!summary_head) + return -ENOMEM; - INIT_LIST_HEAD(&summary_head->domain_head); + summary_head->cpu_data = zalloc(sizeof(*summary_head->cpu_data)); + memcpy(summary_head->cpu_data, cptr->cpu_data, sizeof(*summary_head->cpu_data)); - list_for_each_entry(dptr, &cptr->domain_head, domain_list) { - tdptr = zalloc(sizeof(*tdptr)); - if (!tdptr) - return -ENOMEM; + INIT_LIST_HEAD(&summary_head->domain_head); - tdptr->domain_data = zalloc(sizeof(*ds)); - if (!tdptr->domain_data) - return -ENOMEM; + list_for_each_entry(dptr, &cptr->domain_head, domain_list) { + struct schedstat_domain *tdptr = zalloc(sizeof(*tdptr)); - memcpy(tdptr->domain_data, dptr->domain_data, sizeof(*ds)); - list_add_tail(&tdptr->domain_list, &summary_head->domain_head); - } + if (!tdptr) + return -ENOMEM; + + tdptr->domain_data = zalloc(sizeof(*tdptr->domain_data)); + if (!tdptr->domain_data) + return -ENOMEM; + + memcpy(tdptr->domain_data, dptr->domain_data, sizeof(*tdptr->domain_data)); + list_add_tail(&tdptr->domain_list, &summary_head->domain_head); } list_for_each_entry(cptr, head, cpu_list) { + struct schedstat_domain *tdptr; + if (list_is_first(&cptr->cpu_list, head)) continue; @@ -4212,32 +4212,47 @@ static int get_all_cpu_stats(struct list_head *head) cnt++; summarize_schedstat_cpu(summary_head, cptr, cnt, is_last); + if (list_empty(&summary_head->domain_head)) + continue; + tdptr = list_first_entry(&summary_head->domain_head, struct schedstat_domain, domain_list); list_for_each_entry(dptr, &cptr->domain_head, domain_list) { summarize_schedstat_domain(tdptr, dptr, cnt, is_last); + if (list_is_last(&tdptr->domain_list, &summary_head->domain_head)) { + tdptr = NULL; + break; + } tdptr = list_next_entry(tdptr, domain_list); } } list_add(&summary_head->cpu_list, head); - return ret; + return 0; } -static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map **cd_map1, - struct list_head *head2, struct cpu_domain_map **cd_map2, +static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map **cd_map1, int nr1, + struct list_head *head2, struct cpu_domain_map **cd_map2, int nr2, bool summary_only) { struct schedstat_cpu *cptr1 = list_first_entry(head1, struct schedstat_cpu, cpu_list); struct perf_record_schedstat_domain *ds1 = NULL, *ds2 = NULL; - struct perf_record_schedstat_cpu *cs1 = NULL, *cs2 = NULL; struct schedstat_domain *dptr1 = NULL, *dptr2 = NULL; struct schedstat_cpu *cptr2 = NULL; __u64 jiffies1 = 0, jiffies2 = 0; bool is_summary = true; int ret = 0; + if (!cd_map1) { + pr_err("Error: CPU domain map 1 is missing.\n"); + return -1; + } + if (head2 && !cd_map2) { + pr_err("Error: CPU domain map 2 is missing.\n"); + return -1; + } + printf("Description\n"); print_separator2(SEP_LEN, "", 0); printf("%-30s-> %s\n", "DESC", "Description of the field"); @@ -4267,14 +4282,36 @@ static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map ** list_for_each_entry(cptr1, head1, cpu_list) { struct cpu_domain_map *cd_info1 = NULL, *cd_info2 = NULL; + struct perf_record_schedstat_cpu *cs1 = cptr1->cpu_data; + struct perf_record_schedstat_cpu *cs2 = NULL; - cs1 = cptr1->cpu_data; + dptr2 = NULL; + if (cs1->cpu >= (u32)nr1) { + pr_err("Error: CPU %d exceeds domain map size %d\n", cs1->cpu, nr1); + return -1; + } cd_info1 = cd_map1[cs1->cpu]; + if (!cd_info1) { + pr_err("Error: CPU %d domain info is missing in map 1.\n", + cs1->cpu); + return -1; + } if (cptr2) { cs2 = cptr2->cpu_data; + if (cs2->cpu >= (u32)nr2) { + pr_err("Error: CPU %d exceeds domain map size %d\n", cs2->cpu, nr2); + return -1; + } cd_info2 = cd_map2[cs2->cpu]; - dptr2 = list_first_entry(&cptr2->domain_head, struct schedstat_domain, - domain_list); + if (!cd_info2) { + pr_err("Error: CPU %d domain info is missing in map 2.\n", + cs2->cpu); + return -1; + } + if (!list_empty(&cptr2->domain_head)) + dptr2 = list_first_entry(&cptr2->domain_head, + struct schedstat_domain, + domain_list); } if (cs2 && cs1->cpu != cs2->cpu) { @@ -4302,10 +4339,30 @@ static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map ** struct domain_info *dinfo1 = NULL, *dinfo2 = NULL; ds1 = dptr1->domain_data; + if (ds1->domain >= cd_info1->nr_domains) { + pr_err("Error: Domain %d exceeds max domains %d for CPU %d in map 1.\n", + ds1->domain, cd_info1->nr_domains, cs1->cpu); + return -1; + } dinfo1 = cd_info1->domains[ds1->domain]; + if (!dinfo1) { + pr_err("Error: Domain %d info is missing for CPU %d in map 1.\n", + ds1->domain, cs1->cpu); + return -1; + } if (dptr2) { ds2 = dptr2->domain_data; + if (ds2->domain >= cd_info2->nr_domains) { + pr_err("Error: Domain %d exceeds max domains %d for CPU %d in map 2.\n", + ds2->domain, cd_info2->nr_domains, cs2->cpu); + return -1; + } dinfo2 = cd_info2->domains[ds2->domain]; + if (!dinfo2) { + pr_err("Error: Domain %d info is missing for CPU %d in map 2.\n", + ds2->domain, cs2->cpu); + return -1; + } } if (dinfo2 && dinfo1->domain != dinfo2->domain) { @@ -4334,14 +4391,22 @@ static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map ** print_domain_stats(ds1, ds2, jiffies1, jiffies2); print_separator2(SEP_LEN, "", 0); - if (dptr2) - dptr2 = list_next_entry(dptr2, domain_list); + if (dptr2) { + if (list_is_last(&dptr2->domain_list, &cptr2->domain_head)) + dptr2 = NULL; + else + dptr2 = list_next_entry(dptr2, domain_list); + } } if (summary_only) break; - if (cptr2) - cptr2 = list_next_entry(cptr2, cpu_list); + if (cptr2) { + if (list_is_last(&cptr2->cpu_list, head2)) + cptr2 = NULL; + else + cptr2 = list_next_entry(cptr2, cpu_list); + } is_summary = false; } @@ -4523,7 +4588,9 @@ static int perf_sched__schedstat_report(struct perf_sched *sched) } cd_map = session->header.env.cpu_domain; - err = show_schedstat_data(&cpu_head, cd_map, NULL, NULL, false); + err = show_schedstat_data(&cpu_head, cd_map, + session->header.env.nr_cpus_avail, + NULL, NULL, 0, false); } out: @@ -4538,7 +4605,7 @@ 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", @@ -4610,7 +4677,8 @@ static int perf_sched__schedstat_diff(struct perf_sched *sched, goto out_delete_ses0; } - show_schedstat_data(&cpu_head_ses0, cd_map0, &cpu_head_ses1, cd_map1, true); + show_schedstat_data(&cpu_head_ses0, cd_map0, session[0]->header.env.nr_cpus_avail, + &cpu_head_ses1, cd_map1, session[1]->header.env.nr_cpus_avail, true); out_delete_ses1: free_schedstat(&cpu_head_ses1); @@ -4720,7 +4788,7 @@ static int perf_sched__schedstat_live(struct perf_sched *sched, goto out; } - show_schedstat_data(&cpu_head, cd_map, NULL, NULL, false); + show_schedstat_data(&cpu_head, cd_map, nr, NULL, NULL, 0, false); free_cpu_domain_info(cd_map, sv, nr); out: free_schedstat(&cpu_head); -- 2.54.0.545.g6539524ca2-goog