From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f73.google.com (mail-dl1-f73.google.com [74.125.82.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6CF63B3C10 for ; Sat, 25 Apr 2026 22:52:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777157541; cv=none; b=S4hRp9bV6Gh85QzxgezS7uLNKaDGJXkhuE/wrr4QkhWqqIiRBNouGrW94zniCjKZn5c4+BwHkAulO0viHlj8ik8thPq9eLkWEUpo9kuD3XZfTiet1y8r9SwK1ZWc8a3TumJAd6aaXBU47/BfDQ12g1Z6NdZpMllcZiWLIb1BWAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777157541; c=relaxed/simple; bh=b8WChMU2GFjZaAMy6D9g7SBa1GQPwudhcSXhEV1GN7A=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=RXOANWmqQ9pmBpGobEB+GzGzF80n85SHz1o7Z+debiT8cKyxu2JUKhvYDRqpZ1rJbF5rVR6UCzUD+krROSrq4N8kwSuZIPNxBU+ippSy+Rz2ENODKiHmd9UMP20PTuKc8Eo61zmspaeCSp6moGxcmg9lVDulo5lCSOVd9qJb1Sg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=rWr2KJ0P; arc=none smtp.client-ip=74.125.82.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rWr2KJ0P" Received: by mail-dl1-f73.google.com with SMTP id a92af1059eb24-126e8ee6227so9133595c88.0 for ; Sat, 25 Apr 2026 15:52:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1777157537; x=1777762337; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=OlWrNjVnLs3USTmPSqIGY0FmcUo+LUNpaODSh5R9ico=; b=rWr2KJ0Ph1FkpA4POYAAyK4sLHB+RVt3XWpYgYDmcW5NaKzwdAbF9rz/eTDm1QFywo MrGlbplgpQhDM8hf4mu4I17uQWrXmGirNvLrj/ETLskaEvX3ZwIfALHUZGwOKtdP+1fN b8m2VApNtU3FHfotPqlaHKgvRAV4pBKjfQZp0K5CyqK9ciIirX9I673NKKS7O+X75De/ Uuc8H7oQ8Yr/rzEveQRNi0BtUWyTd7rrb0sW70548jUabbzWZ1aFisCFwux5JYfZ89hM itSp8tuZYP4tAv0LYI/nf93fNAAa0GB2Lli0+ZiHa4AjkvLxnBkCMNcyuByIwKmnYd2k hqzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777157537; x=1777762337; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OlWrNjVnLs3USTmPSqIGY0FmcUo+LUNpaODSh5R9ico=; b=k8p1OK/00xwNssb8O4STScRHYFDNLW3oU3+xp2lEN4vz/JLu44usRnCHQidb5795MD 7gd/4BsX5p7zN3dsuhKSgwdWL3/ajUoNLQ7hRtyuWpdi5OyiGdYxTWh49ytUs9KylB4w xuoCXDovPryvGLbxX647H8UXhI4VX/vxGAwTYotAV7t5uAYEVKVcszXckSfDlTFms1Hz y6iczygud8vywSp1eOpZDErneyMn0oRzkhPJBLUykpVXdnjgHUO/PtkjZ+uR57ykkT59 4LshPp6vy/izd8mFelmPnvdm6i1B1TGruFXgC3Yk2FzwCb4+XKpRYWNOwhIF8hdMJCMO lAmg== X-Forwarded-Encrypted: i=1; AFNElJ8RX3dbPMoGcf3L+D7C7GlCIOcjyd6GdXKgASPKgmxE3fzqWcXLjdgtUDkLWcVKrzFJ4oZxewkfRhRWJlkeO/ZN@vger.kernel.org X-Gm-Message-State: AOJu0Ywg9DzsQ4jPCdMCBtL6b8zMcVcH8+txXfkZNgH6uOgHgrVu5a8n 09luW8AuiEvpm0SbdGOoYFTbbvVYUAPMcgxQSHbSvN2KmVXbKuC4qvXOPtKbJrI7RCfK3lL+SNA /de78XrRhEg== X-Received: from dlbrh4.prod.google.com ([2002:a05:7022:f304:b0:12b:eb91:8863]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:23a1:b0:12d:ce34:3fa0 with SMTP id a92af1059eb24-12dce344079mr1783349c88.32.1777157536815; Sat, 25 Apr 2026 15:52:16 -0700 (PDT) Date: Sat, 25 Apr 2026 15:49:51 -0700 In-Reply-To: <20260425224951.174663-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260425174858.3922152-1-irogers@google.com> <20260425224951.174663-1-irogers@google.com> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260425224951.174663-60-irogers@google.com> Subject: [PATCH v7 59/59] perf sched stats: Fix segmentation faults in diff mode From: Ian Rogers To: acme@kernel.org, adrian.hunter@intel.com, james.clark@linaro.org, leo.yan@linux.dev, namhyung@kernel.org, tmricht@linux.ibm.com Cc: alice.mei.rogers@gmail.com, dapeng1.mi@linux.intel.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, Ian Rogers Content-Type: text/plain; charset="UTF-8" Address several segmentation fault vectors in `perf sched stats diff`: 1. When processing invalid or empty data files, the CPU domain maps may be NULL. Added NULL checks for `cd_map1` and `cd_map2` in `show_schedstat_data()` to fail gracefully. 2. When files contain a different number of CPUs or domains, the parallel list iteration in `show_schedstat_data()` could wrap around the list heads and dereference invalid memory. Added `list_is_last` checks to safely terminate iteration at the end of each list. 3. When summarizing CPU statistics in `get_all_cpu_stats()`, parallel list iteration over domains could similarly wrap around if a CPU has more domains than the first CPU. Added `list_is_last` check to prevent this. 4. Added bounds checks for `cs1->cpu` and `cs2->cpu` against `nr1` and `nr2` (passed from `env->nr_cpus_avail`) to prevent out-of-bounds reads from `cd_map1` and `cd_map2` when processing data from machines with different CPU configurations. 5. Added NULL checks for `cd_info1` and `cd_info2` in `show_schedstat_data()` to prevent crashes when a CPU has samples in the data file but no corresponding domain info in the header (which leaves the map entry NULL). 6. Added NULL checks for `dinfo1` and `dinfo2` in `show_schedstat_data()` to prevent crashes when a domain is present in the list but has no corresponding info in the CPU domain map (which leaves the entry NULL). 7. 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 --- tools/perf/builtin-sched.c | 85 +++++++++++++++++++++++++++++++------- 1 file changed, 69 insertions(+), 16 deletions(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index d3fa9c70790f..f6c7d100729a 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -4212,12 +4212,20 @@ static int get_all_cpu_stats(struct list_head *head) cnt++; summarize_schedstat_cpu(summary_head, cptr, cnt, is_last); - tdptr = list_first_entry(&summary_head->domain_head, struct schedstat_domain, - domain_list); + if (!list_empty(&summary_head->domain_head)) + tdptr = list_first_entry(&summary_head->domain_head, struct schedstat_domain, + domain_list); + else + tdptr = NULL; list_for_each_entry(dptr, &cptr->domain_head, domain_list) { - summarize_schedstat_domain(tdptr, dptr, cnt, is_last); - tdptr = list_next_entry(tdptr, domain_list); + if (tdptr) { + summarize_schedstat_domain(tdptr, dptr, cnt, is_last); + if (list_is_last(&tdptr->domain_list, &summary_head->domain_head)) + tdptr = NULL; + else + tdptr = list_next_entry(tdptr, domain_list); + } } } @@ -4225,8 +4233,8 @@ static int get_all_cpu_stats(struct list_head *head) return ret; } -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); @@ -4238,6 +4246,15 @@ static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map ** 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"); @@ -4269,12 +4286,31 @@ static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map ** struct cpu_domain_map *cd_info1 = NULL, *cd_info2 = NULL; cs1 = cptr1->cpu_data; + 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); + else + dptr2 = NULL; } if (cs2 && cs1->cpu != cs2->cpu) { @@ -4303,9 +4339,17 @@ static int show_schedstat_data(struct list_head *head1, struct cpu_domain_map ** ds1 = dptr1->domain_data; 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; 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 +4378,22 @@ 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 +4575,7 @@ 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 +4590,7 @@ 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 +4662,8 @@ 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 +4773,7 @@ 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