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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 56DB0C388F7 for ; Fri, 9 Oct 2020 19:51:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24E2222282 for ; Fri, 9 Oct 2020 19:51:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403913AbgJITvZ (ORCPT ); Fri, 9 Oct 2020 15:51:25 -0400 Received: from mga11.intel.com ([192.55.52.93]:40417 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403855AbgJITvJ (ORCPT ); Fri, 9 Oct 2020 15:51:09 -0400 IronPort-SDR: 5U3LdD8JD30Qiz2Xw/HSuDHohT2eTnGXIdf1M2uidm99cBYL2HhALZbtzhz8H9lsGnLyzZh9ts a1oLaFItUWyw== X-IronPort-AV: E=McAfee;i="6000,8403,9769"; a="162067789" X-IronPort-AV: E=Sophos;i="5.77,355,1596524400"; d="scan'208";a="162067789" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2020 12:51:07 -0700 IronPort-SDR: q86t8daZNt+V6d8RNukEYKSCMEs+oCo1U1vd6Yq1DOlnqrvHVUOvZ3CGMAsBzz1plldsK41yyY 6uUXC42AACQg== X-IronPort-AV: E=Sophos;i="5.77,355,1596524400"; d="scan'208";a="317146961" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2020 12:51:06 -0700 From: ira.weiny@intel.com To: Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra Cc: Ira Weiny , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , x86@kernel.org, Dave Hansen , Dan Williams , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kexec@lists.infradead.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, devel@driverdev.osuosl.org, linux-efi@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-um@lists.infradead.org, linux-ntfs-dev@lists.sourceforge.net, reiserfs-devel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org, cluster-devel@redhat.com, ecryptfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-afs@lists.infradead.org, linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, xen-devel@lists.xenproject.org, linux-cachefs@redhat.com, samba-technical@lists.samba.org, intel-wired-lan@lists.osuosl.org Subject: [PATCH RFC PKS/PMEM 06/58] kmap: Introduce k[un]map_thread debugging Date: Fri, 9 Oct 2020 12:49:41 -0700 Message-Id: <20201009195033.3208459-7-ira.weiny@intel.com> X-Mailer: git-send-email 2.28.0.rc0.12.gb6a658bd00c9 In-Reply-To: <20201009195033.3208459-1-ira.weiny@intel.com> References: <20201009195033.3208459-1-ira.weiny@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org From: Ira Weiny Most kmap() callers use the map within a single thread and have no need for the protection domain to be enabled globally. To differentiate these kmap users, new k[un]map_thread() calls were introduced which are thread local. To aid in debugging the new use of kmap_thread(), add a reference count, a check on that count, and tracing to ID where mapping errors occur. Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Signed-off-by: Ira Weiny --- include/linux/highmem.h | 5 +++ include/linux/sched.h | 5 +++ include/trace/events/kmap_thread.h | 56 ++++++++++++++++++++++++++++++ init/init_task.c | 3 ++ kernel/fork.c | 15 ++++++++ lib/Kconfig.debug | 8 +++++ mm/debug.c | 23 ++++++++++++ 7 files changed, 115 insertions(+) create mode 100644 include/trace/events/kmap_thread.h diff --git a/include/linux/highmem.h b/include/linux/highmem.h index ef7813544719..22d1c000802e 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -247,6 +247,10 @@ static inline void kunmap(struct page *page) __kunmap(page, true); } +#ifdef CONFIG_DEBUG_KMAP_THREAD +void *kmap_thread(struct page *page); +void kunmap_thread(struct page *page); +#else static inline void *kmap_thread(struct page *page) { return __kmap(page, false); @@ -255,6 +259,7 @@ static inline void kunmap_thread(struct page *page) { __kunmap(page, false); } +#endif /* * Prevent people trying to call kunmap_atomic() as if it were kunmap() diff --git a/include/linux/sched.h b/include/linux/sched.h index 25d97ab6c757..4627ea4a49e6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1318,6 +1318,11 @@ struct task_struct { #ifdef CONFIG_ZONE_DEVICE_ACCESS_PROTECTION unsigned int dev_page_access_ref; #endif + +#ifdef CONFIG_DEBUG_KMAP_THREAD + unsigned int kmap_thread_cnt; +#endif + /* * New fields for task_struct should be added above here, so that * they are included in the randomized portion of task_struct. diff --git a/include/trace/events/kmap_thread.h b/include/trace/events/kmap_thread.h new file mode 100644 index 000000000000..e7143cfe0daf --- /dev/null +++ b/include/trace/events/kmap_thread.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */ + +/* + * Copyright (c) 2020 Intel Corporation. All rights reserved. + * + */ + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM kmap_thread + +#if !defined(_TRACE_KMAP_THREAD_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_KMAP_THREAD_H + +#include + +DECLARE_EVENT_CLASS(kmap_thread_template, + TP_PROTO(struct task_struct *tsk, struct page *page, + void *caller_addr, int cnt), + TP_ARGS(tsk, page, caller_addr, cnt), + + TP_STRUCT__entry( + __field(int, pid) + __field(struct page *, page) + __field(void *, caller_addr) + __field(int, cnt) + ), + + TP_fast_assign( + __entry->pid = tsk->pid; + __entry->page = page; + __entry->caller_addr = caller_addr; + __entry->cnt = cnt; + ), + + TP_printk("PID %d; (%d) %pS %p", + __entry->pid, + __entry->cnt, + __entry->caller_addr, + __entry->page + ) +); + +DEFINE_EVENT(kmap_thread_template, kmap_thread, + TP_PROTO(struct task_struct *tsk, struct page *page, + void *caller_addr, int cnt), + TP_ARGS(tsk, page, caller_addr, cnt)); + +DEFINE_EVENT(kmap_thread_template, kunmap_thread, + TP_PROTO(struct task_struct *tsk, struct page *page, + void *caller_addr, int cnt), + TP_ARGS(tsk, page, caller_addr, cnt)); + + +#endif /* _TRACE_KMAP_THREAD_H */ + +#include diff --git a/init/init_task.c b/init/init_task.c index 9b39f25de59b..19f09965eb34 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -212,6 +212,9 @@ struct task_struct init_task #ifdef CONFIG_ZONE_DEVICE_ACCESS_PROTECTION .dev_page_access_ref = 0, #endif +#ifdef CONFIG_DEBUG_KMAP_THREAD + .kmap_thread_cnt = 0, +#endif }; EXPORT_SYMBOL(init_task); diff --git a/kernel/fork.c b/kernel/fork.c index b6a3ee328a89..2c66e49b7614 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -722,6 +722,17 @@ static inline void put_signal_struct(struct signal_struct *sig) free_signal_struct(sig); } +#ifdef CONFIG_DEBUG_KMAP_THREAD +static void check_outstanding_kmap_thread(struct task_struct *tsk) +{ + if (tsk->kmap_thread_cnt) + pr_warn(KERN_ERR "WARNING: PID %d; Failed to kunmap_thread() [cnt %d]\n", + tsk->pid, tsk->kmap_thread_cnt); +} +#else +static void check_outstanding_kmap_thread(struct task_struct *tsk) { } +#endif + void __put_task_struct(struct task_struct *tsk) { WARN_ON(!tsk->exit_state); @@ -734,6 +745,7 @@ void __put_task_struct(struct task_struct *tsk) exit_creds(tsk); delayacct_tsk_free(tsk); put_signal_struct(tsk->signal); + check_outstanding_kmap_thread(tsk); if (!profile_handoff_task(tsk)) free_task(tsk); @@ -943,6 +955,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) #endif #ifdef CONFIG_ZONE_DEVICE_ACCESS_PROTECTION tsk->dev_page_access_ref = 0; +#endif +#ifdef CONFIG_DEBUG_KMAP_THREAD + tsk->kmap_thread_cnt = 0; #endif return tsk; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index f015c09ba5a1..6507b43d5b0c 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -858,6 +858,14 @@ config DEBUG_HIGHMEM This option enables additional error checking for high memory systems. Disable for production systems. +config DEBUG_KMAP_THREAD + bool "Kmap debugging" + depends on DEBUG_KERNEL + help + This option enables additional error checking for kernel mapping code + specifically the k[un]map_thread() calls. Disable for production + systems. + config HAVE_DEBUG_STACKOVERFLOW bool diff --git a/mm/debug.c b/mm/debug.c index ca8d1cacdecc..68d186f3570e 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -320,3 +320,26 @@ void page_init_poison(struct page *page, size_t size) } EXPORT_SYMBOL_GPL(page_init_poison); #endif /* CONFIG_DEBUG_VM */ + +#define CREATE_TRACE_POINTS +#include + +#ifdef CONFIG_DEBUG_KMAP_THREAD +void *kmap_thread(struct page *page) +{ + trace_kmap_thread(current, page, __builtin_return_address(0), + current->kmap_thread_cnt); + current->kmap_thread_cnt++; + return __kmap(page, false); +} +EXPORT_SYMBOL_GPL(kmap_thread); + +void kunmap_thread(struct page *page) +{ + __kunmap(page, false); + current->kmap_thread_cnt--; + trace_kunmap_thread(current, page, __builtin_return_address(0), + current->kmap_thread_cnt); +} +EXPORT_SYMBOL_GPL(kunmap_thread); +#endif -- 2.28.0.rc0.12.gb6a658bd00c9