From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19A6AC2B9F4 for ; Mon, 28 Jun 2021 14:19:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0425261C82 for ; Mon, 28 Jun 2021 14:19:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233059AbhF1OV1 (ORCPT ); Mon, 28 Jun 2021 10:21:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:54376 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232754AbhF1OVQ (ORCPT ); Mon, 28 Jun 2021 10:21:16 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4673961C86; Mon, 28 Jun 2021 14:18:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624889927; bh=eYZ+2eym8ZBweDaDbAmqdT1Jl98Aj8FvzCQhjRd5LV0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YeyBAQxadYVoHCdxvNUtlaH7m50G1KYT4VcfUc4qi69scJOW+t5X2H2PftSY0mCFk v/GclURQzo8GQXdWak22t03tBkppv1V7Au6grfCvcr/yE5IDKuQ9DDpvkoJxKeptZx K4g0OysimRLL7p3uYC4cziyc7Fe5OjYrx7mCSZWCx0mLE3LZjAHhvH17lWCUHvOlzk SDZx1Nmr4AT3TaEMviotprAtoX61kbP3L5ubGN3oB+59B6LtGjN4Gx+DE35dmeBgP8 m8w3SB9hcjX26VynaXR7lF22cylUx5Rfwm/M9oORNpSrzLKZN8UoSl5s5ZwZnj5Bz9 rj0c/5yFsfZ9Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Like Xu , Peter Zijlstra , Kan Liang , Sasha Levin Subject: [PATCH 5.12 020/110] perf/x86/lbr: Remove cpuc->lbr_xsave allocation from atomic context Date: Mon, 28 Jun 2021 10:16:58 -0400 Message-Id: <20210628141828.31757-21-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628141828.31757-1-sashal@kernel.org> References: <20210628141828.31757-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.12.14-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.12.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.12.14-rc1 X-KernelTest-Deadline: 2021-06-30T14:18+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Like Xu [ Upstream commit 488e13a489e9707a7e81e1991fdd1f20c0f04689 ] If the kernel is compiled with the CONFIG_LOCKDEP option, the conditional might_sleep_if() deep in kmem_cache_alloc() will generate the following trace, and potentially cause a deadlock when another LBR event is added: [] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:196 [] Call Trace: [] kmem_cache_alloc+0x36/0x250 [] intel_pmu_lbr_add+0x152/0x170 [] x86_pmu_add+0x83/0xd0 Make it symmetric with the release_lbr_buffers() call and mirror the existing DS buffers. Fixes: c085fb8774 ("perf/x86/intel/lbr: Support XSAVES for arch LBR read") Signed-off-by: Like Xu [peterz: simplified] Signed-off-by: Peter Zijlstra (Intel) Tested-by: Kan Liang Link: https://lkml.kernel.org/r/20210430052247.3079672-2-like.xu@linux.intel.com Signed-off-by: Sasha Levin --- arch/x86/events/core.c | 6 ++++-- arch/x86/events/intel/lbr.c | 26 ++++++++++++++++++++------ arch/x86/events/perf_event.h | 6 ++++++ 3 files changed, 30 insertions(+), 8 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 18df17129695..10cadd73a8ac 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -380,10 +380,12 @@ int x86_reserve_hardware(void) if (!atomic_inc_not_zero(&pmc_refcount)) { mutex_lock(&pmc_reserve_mutex); if (atomic_read(&pmc_refcount) == 0) { - if (!reserve_pmc_hardware()) + if (!reserve_pmc_hardware()) { err = -EBUSY; - else + } else { reserve_ds_buffers(); + reserve_lbr_buffers(); + } } if (!err) atomic_inc(&pmc_refcount); diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 21890dacfcfe..22d0e40a1920 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -658,7 +658,6 @@ static inline bool branch_user_callstack(unsigned br_sel) void intel_pmu_lbr_add(struct perf_event *event) { - struct kmem_cache *kmem_cache = event->pmu->task_ctx_cache; struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); if (!x86_pmu.lbr_nr) @@ -696,11 +695,6 @@ void intel_pmu_lbr_add(struct perf_event *event) perf_sched_cb_inc(event->ctx->pmu); if (!cpuc->lbr_users++ && !event->total_time_running) intel_pmu_lbr_reset(); - - if (static_cpu_has(X86_FEATURE_ARCH_LBR) && - kmem_cache && !cpuc->lbr_xsave && - (cpuc->lbr_users != cpuc->lbr_pebs_users)) - cpuc->lbr_xsave = kmem_cache_alloc(kmem_cache, GFP_KERNEL); } void release_lbr_buffers(void) @@ -721,6 +715,26 @@ void release_lbr_buffers(void) } } +void reserve_lbr_buffers(void) +{ + struct kmem_cache *kmem_cache; + struct cpu_hw_events *cpuc; + int cpu; + + if (!static_cpu_has(X86_FEATURE_ARCH_LBR)) + return; + + for_each_possible_cpu(cpu) { + cpuc = per_cpu_ptr(&cpu_hw_events, cpu); + kmem_cache = x86_get_pmu(cpu)->task_ctx_cache; + if (!kmem_cache || cpuc->lbr_xsave) + continue; + + cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, GFP_KERNEL, + cpu_to_node(cpu)); + } +} + void intel_pmu_lbr_del(struct perf_event *event) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 53b2b5fc23bc..7888266c76cd 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1135,6 +1135,8 @@ void reserve_ds_buffers(void); void release_lbr_buffers(void); +void reserve_lbr_buffers(void); + extern struct event_constraint bts_constraint; extern struct event_constraint vlbr_constraint; @@ -1282,6 +1284,10 @@ static inline void release_lbr_buffers(void) { } +static inline void reserve_lbr_buffers(void) +{ +} + static inline int intel_pmu_init(void) { return 0; -- 2.30.2