From nobody Mon Apr 6 20:12:44 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 9CF74ECAAD5 for ; Fri, 2 Sep 2022 08:33:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235815AbiIBIdz (ORCPT ); Fri, 2 Sep 2022 04:33:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235804AbiIBIcn (ORCPT ); Fri, 2 Sep 2022 04:32:43 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C37BC1230; Fri, 2 Sep 2022 01:32:41 -0700 (PDT) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MJrdn5mV2zRhSy; Fri, 2 Sep 2022 16:28:13 +0800 (CST) Received: from kwepemm600003.china.huawei.com (7.193.23.202) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 2 Sep 2022 16:32:39 +0800 Received: from ubuntu1804.huawei.com (10.67.174.61) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 2 Sep 2022 16:32:38 +0800 From: Yang Jihong To: , , , , , , , , , CC: Subject: [PATCH RESEND v4] perf/core: Fix reentry problem in perf_output_read_group Date: Fri, 2 Sep 2022 16:29:18 +0800 Message-ID: <20220902082918.179248-1-yangjihong1@huawei.com> X-Mailer: git-send-email 2.30.GIT MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.67.174.61] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" perf_output_read_group may respond to IPI request of other cores and invoke __perf_install_in_context function. As a result, hwc configuration is modif= ied. causing inconsistency and unexpected consequences. Syzkaller has reported a problem with this scenario: Internal error: Oops - undefined instruction: 0 [#1] SMP Modules linked in: CPU: 1 PID: 15523 Comm: syz-executor.3 Not tainted 5.10.0 #6 Hardware name: linux,dummy-virt (DT) pstate: 80400005 (Nzcv daif +PAN -UAO -TCO BTYPE=3D--) pc : read_pmevcntrn+0x1e4/0x1ec arch/arm64/kernel/perf_event.c:423 lr : read_pmevcntrn+0x1e4/0x1ec arch/arm64/kernel/perf_event.c:423 sp : ffffa000174d6ee0 x29: ffffa000174d6ee0 x28: ffffedbca6b17a40 x27: ffffa000174d7310 x26: ffff4b3ec102e398 x25: 00000000ffffffff x24: 00000000ffffffff x23: ffff4b3ed8afb000 x22: ffff4b3ed8afb160 x21: ffff4b3ed8afb184 x20: ffffedbca46aa3e0 x19: ffffedbca2a524bc x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000020000100 x14: 0000000000000000 x13: 0000000000000000 x12: ffff8967db15f63d x11: 1fffe967db15f63c x10: ffff8967db15f63c x9 : ffffedbca2a5273c x8 : ffff4b3ed8afb1e7 x7 : 0000000000000001 x6 : ffff8967db15f63c x5 : ffff4b3f08b89400 x4 : 0000000000000000 x3 : ffffedbca2a00000 x2 : ffffedbca4690000 x1 : ffff4b3f08b89400 x0 : 0000000000000000 Call trace: read_pmevcntrn+0x1e4/0x1ec arch/arm64/kernel/perf_event.c:423 armv8pmu_read_evcntr arch/arm64/kernel/perf_event.c:467 [inline] armv8pmu_read_hw_counter arch/arm64/kernel/perf_event.c:475 [inline] armv8pmu_read_counter+0x10c/0x1f0 arch/arm64/kernel/perf_event.c:528 armpmu_event_update+0x9c/0x1bc drivers/perf/arm_pmu.c:247 armpmu_read+0x24/0x30 drivers/perf/arm_pmu.c:264 perf_output_read_group+0x4cc/0x71c kernel/events/core.c:6806 perf_output_read+0x78/0x1c4 kernel/events/core.c:6845 perf_output_sample+0xafc/0x1000 kernel/events/core.c:6892 __perf_event_output kernel/events/core.c:7273 [inline] perf_event_output_forward+0xd8/0x130 kernel/events/core.c:7287 __perf_event_overflow+0xbc/0x20c kernel/events/core.c:8943 perf_swevent_overflow kernel/events/core.c:9019 [inline] perf_swevent_event+0x274/0x2c0 kernel/events/core.c:9047 do_perf_sw_event kernel/events/core.c:9160 [inline] ___perf_sw_event+0x150/0x1b4 kernel/events/core.c:9191 __perf_sw_event+0x58/0x7c kernel/events/core.c:9203 perf_sw_event include/linux/perf_event.h:1177 [inline] mm_account_fault mm/memory.c:4707 [inline] handle_mm_fault+0x364/0x3f0 mm/memory.c:4758 __do_page_fault arch/arm64/mm/fault.c:438 [inline] do_page_fault+0x334/0x8f0 arch/arm64/mm/fault.c:537 do_translation_fault+0x188/0x1e0 arch/arm64/mm/fault.c:619 do_mem_abort+0x68/0x120 arch/arm64/mm/fault.c:743 el1_abort+0xc0/0x150 arch/arm64/kernel/entry-common.c:119 el1_sync_handler+0x118/0x150 arch/arm64/kernel/entry-common.c:202 el1_sync+0x74/0x100 arch/arm64/kernel/entry.S:665 __arch_clear_user+0x20/0xa0 arch/arm64/lib/clear_user.S:25 read_iter_zero+0x90/0x16c drivers/char/mem.c:718 call_read_iter include/linux/fs.h:1954 [inline] do_iter_readv_writev+0x394/0x414 fs/read_write.c:735 do_iter_read+0x1b0/0x280 fs/read_write.c:798 vfs_readv+0xf0/0x150 fs/read_write.c:918 do_readv+0x108/0x270 fs/read_write.c:955 __do_sys_readv fs/read_write.c:1046 [inline] __se_sys_readv fs/read_write.c:1043 [inline] __arm64_sys_readv+0x54/0x64 fs/read_write.c:1043 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common.constprop.0+0xf4/0x414 arch/arm64/kernel/syscall.c:155 do_el0_svc+0x50/0x11c arch/arm64/kernel/syscall.c:217 el0_svc+0x20/0x30 arch/arm64/kernel/entry-common.c:353 el0_sync_handler+0xe4/0x1e0 arch/arm64/kernel/entry-common.c:369 el0_sync+0x148/0x180 arch/arm64/kernel/entry.S:683 Code: 940c387b d53be813 17ffff9c 940c3878 (d53bebd3) ---[ end trace 6aab9f4b33ebf0aa ]--- ---------------- Code disassembly (best guess): 0: 940c387b bl 0x30e1ec 4: d53be813 mrs x19, pmevcntr0_el0 8: 17ffff9c b 0xfffffffffffffe78 c: 940c3878 bl 0x30e1ec * 10: d53bebd3 mrs x19, pmevcntr30_el0 <-- trapping instruction Interrupts are not disabled when perf_output_read_group reads PMU counter. In this case, IPI request may be received from other cores. As a result, PMU configuration is modified and an error occurs when reading PMU counter: CPU0 CPU1 __se_sys_perf_event_open perf_install_in_conte= xt perf_output_read_group smp_call_function_s= ingle for_each_sibling_event(sub, leader) { generic_exec_sing= le if ((sub !=3D event) && remote_functi= on (sub->state =3D=3D PERF_EVENT_STATE_ACTIVE)) | <----RAISE IPI-----+ __perf_install_in_context ctx_resched event_sched_out armpmu_del ... hwc->idx =3D -1; // event->hwc.idx is set to -1 ... sub->pmu->read(sub); armpmu_read armv8pmu_read_counter armv8pmu_read_hw_counter int idx =3D event->hw.idx; // idx =3D -1 u64 val =3D armv8pmu_read_evcntr(idx); u32 counter =3D ARMV8_IDX_TO_COUNTER(idx); // invalid= counter =3D 30 read_pmevcntrn(counter) // undefined instruction Signed-off-by: Yang Jihong --- Changes since v3: - Modify commit message according to Peter's suggestion. Changes since v2: - Update commit message. Changes since v1: - Adapt patch to mainline branch to solve compilation problem. kernel/events/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 2621fd24ad26..752a9079a807 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6895,6 +6895,13 @@ static void perf_output_read_group(struct perf_outpu= t_handle *handle, u64 read_format =3D event->attr.read_format; u64 values[6]; int n =3D 0; + unsigned long flags; + + /* + * Disabling interrupts avoids all counter scheduling + * (context switches, timer based rotation and IPIs). + */ + local_irq_save(flags); =20 values[n++] =3D 1 + leader->nr_siblings; =20 @@ -6931,6 +6938,8 @@ static void perf_output_read_group(struct perf_output= _handle *handle, =20 __output_copy(handle, values, n * sizeof(u64)); } + + local_irq_restore(flags); } =20 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ --=20 2.30.GIT