From nobody Sun Feb 8 07:57:53 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AB90C001DB for ; Fri, 4 Aug 2023 07:32:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234051AbjHDHcc (ORCPT ); Fri, 4 Aug 2023 03:32:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234070AbjHDHcG (ORCPT ); Fri, 4 Aug 2023 03:32:06 -0400 Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E430E46A0; Fri, 4 Aug 2023 00:31:08 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046050;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0Vp.c2JM_1691134193; Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0Vp.c2JM_1691134193) by smtp.aliyun-inc.com; Fri, 04 Aug 2023 15:29:55 +0800 From: Shuai Xue To: alexander.shishkin@linux.intel.com, peterz@infradead.org, james.clark@arm.com, leo.yan@linaro.org Cc: mingo@redhat.com, baolin.wang@linux.alibaba.com, acme@kernel.org, mark.rutland@arm.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, nathan@kernel.org, bpf@vger.kernel.org Subject: [PATCH v4 1/2] perf/core: Bail out early if the request AUX area is out of bound Date: Fri, 4 Aug 2023 15:29:44 +0800 Message-Id: <20230804072945.85731-2-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230804072945.85731-1-xueshuai@linux.alibaba.com> References: <20230804072945.85731-1-xueshuai@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When perf-record with a large AUX area, e.g 4GB, it fails with: #perf record -C 0 -m ,4G -e arm_spe_0// -- sleep 1 failed to mmap with 12 (Cannot allocate memory) and it reveals a WARNING with __alloc_pages(): [ 66.595604] ------------[ cut here ]------------ [ 66.600206] WARNING: CPU: 44 PID: 17573 at mm/page_alloc.c:5568 __alloc_= pages+0x1ec/0x248 [ 66.608375] Modules linked in: ip6table_filter(E) ip6_tables(E) iptable_= filter(E) ebtable_nat(E) ebtables(E) aes_ce_blk(E) vfat(E) fat(E) aes_ce_ci= pher(E) crct10dif_ce(E) ghash_ce(E) sm4_ce_cipher(E) sm4(E) sha2_ce(E) sha2= 56_arm64(E) sha1_ce(E) acpi_ipmi(E) sbsa_gwdt(E) sg(E) ipmi_si(E) ipmi_devi= ntf(E) ipmi_msghandler(E) ip_tables(E) sd_mod(E) ast(E) drm_kms_helper(E) s= yscopyarea(E) sysfillrect(E) nvme(E) sysimgblt(E) i2c_algo_bit(E) nvme_core= (E) drm_shmem_helper(E) ahci(E) t10_pi(E) libahci(E) drm(E) crc64_rocksoft(= E) i40e(E) crc64(E) libata(E) i2c_core(E) [ 66.657719] CPU: 44 PID: 17573 Comm: perf Kdump: loaded Tainted: G = E 6.3.0-rc4+ #58 [ 66.666749] Hardware name: Default Default/Default, BIOS 1.2.M1.AL.P.139= .00 03/22/2023 [ 66.674650] pstate: 23400009 (nzCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE= =3D--) [ 66.681597] pc : __alloc_pages+0x1ec/0x248 [ 66.685680] lr : __kmalloc_large_node+0xc0/0x1f8 [ 66.690285] sp : ffff800020523980 [ 66.693585] pmr_save: 000000e0 [ 66.696624] x29: ffff800020523980 x28: ffff000832975800 x27: 00000000000= 00000 [ 66.703746] x26: 0000000000100000 x25: 0000000000100000 x24: ffff8000083= 615d0 [ 66.710866] x23: 0000000000040dc0 x22: ffff000823d6d140 x21: 00000000000= 0000b [ 66.717987] x20: 000000000000000b x19: 0000000000000000 x18: 00000000000= 00030 [ 66.725108] x17: 0000000000000000 x16: ffff800008f05be8 x15: ffff000823d= 6d6d0 [ 66.732229] x14: 0000000000000000 x13: 343373656761705f x12: 726e202c302= 06574 [ 66.739350] x11: 00000000ffff7fff x10: 00000000ffff7fff x9 : ffff8000083= af570 [ 66.746471] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : 00000000000= 5fff4 [ 66.753592] x5 : 0000000000000000 x4 : ffff000823d6d8d8 x3 : 00000000000= 00000 [ 66.760713] x2 : 0000000000000000 x1 : 0000000000000001 x0 : 00000000000= 40dc0 [ 66.767834] Call trace: [ 66.770267] __alloc_pages+0x1ec/0x248 [ 66.774003] __kmalloc_large_node+0xc0/0x1f8 [ 66.778259] __kmalloc_node+0x134/0x1e8 [ 66.782081] rb_alloc_aux+0xe0/0x298 [ 66.785643] perf_mmap+0x440/0x660 [ 66.789031] mmap_region+0x308/0x8a8 [ 66.792593] do_mmap+0x3c0/0x528 [ 66.795807] vm_mmap_pgoff+0xf4/0x1b8 [ 66.799456] ksys_mmap_pgoff+0x18c/0x218 [ 66.803365] __arm64_sys_mmap+0x38/0x58 [ 66.807187] invoke_syscall+0x50/0x128 [ 66.810922] el0_svc_common.constprop.0+0x58/0x188 [ 66.815698] do_el0_svc+0x34/0x50 [ 66.818999] el0_svc+0x34/0x108 [ 66.822127] el0t_64_sync_handler+0xb8/0xc0 [ 66.826296] el0t_64_sync+0x1a4/0x1a8 [ 66.829946] ---[ end trace 0000000000000000 ]--- 'rb->aux_pages' allocated by kcalloc() is a pointer array which is used to maintains AUX trace pages. The allocated page for this array is physically contiguous (and virtually contiguous) with an order of 0..MAX_ORDER. If the size of pointer array crosses the limitation set by MAX_ORDER, it reveals a WARNING. So bail out early with -ENOMEM if the request AUX area is out of bound, e.g.: #perf record -C 0 -m ,4G -e arm_spe_0// -- sleep 1 failed to mmap with 12 (Cannot allocate memory) Signed-off-by: Shuai Xue --- kernel/events/ring_buffer.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index a0433f37b024..c445e927368d 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -699,6 +699,9 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_ev= ent *event, watermark =3D 0; } =20 + /* Can't allocate more than MAX_ORDER */ + if (get_order((unsigned long)nr_pages * sizeof(void *)) > MAX_ORDER) + return -ENOMEM; rb->aux_pages =3D kcalloc_node(nr_pages, sizeof(void *), GFP_KERNEL, node); if (!rb->aux_pages) --=20 2.39.3 From nobody Sun Feb 8 07:57:53 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FA0AC001DB for ; Fri, 4 Aug 2023 07:32:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234327AbjHDHca (ORCPT ); Fri, 4 Aug 2023 03:32:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233944AbjHDHcD (ORCPT ); Fri, 4 Aug 2023 03:32:03 -0400 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BDCC14EE0; Fri, 4 Aug 2023 00:31:03 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R641e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0Vp.c2KL_1691134195; Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0Vp.c2KL_1691134195) by smtp.aliyun-inc.com; Fri, 04 Aug 2023 15:29:56 +0800 From: Shuai Xue To: alexander.shishkin@linux.intel.com, peterz@infradead.org, james.clark@arm.com, leo.yan@linaro.org Cc: mingo@redhat.com, baolin.wang@linux.alibaba.com, acme@kernel.org, mark.rutland@arm.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, nathan@kernel.org, bpf@vger.kernel.org Subject: [PATCH v4 2/2] perf record: Update docs regarding the maximum limitation of AUX area Date: Fri, 4 Aug 2023 15:29:45 +0800 Message-Id: <20230804072945.85731-3-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230804072945.85731-1-xueshuai@linux.alibaba.com> References: <20230804072945.85731-1-xueshuai@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The maximum AUX area is limited by the page size of the system. Update the documentation to reflect this. Signed-off-by: Shuai Xue --- tools/perf/Documentation/perf-record.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Document= ation/perf-record.txt index 680396c56bd1..b0ee7b63da0e 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -292,6 +292,9 @@ OPTIONS Also, by adding a comma, the number of mmap pages for AUX area tracing can be specified. =20 + The maximum AUX area is limited by the page size of the system. For + example with 4K pages configured, the maximum is 2GiB. + -g:: Enables call-graph (stack chain/backtrace) recording for both kernel space and user space. --=20 2.39.3