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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no 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 19E8DC432C3 for ; Sun, 1 Dec 2019 01:50:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C2799217AB for ; Sun, 1 Dec 2019 01:50:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Cnq+ZFLS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C2799217AB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6E5B86B028C; Sat, 30 Nov 2019 20:50:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 696366B028E; Sat, 30 Nov 2019 20:50:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5AC966B028F; Sat, 30 Nov 2019 20:50:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0197.hostedemail.com [216.40.44.197]) by kanga.kvack.org (Postfix) with ESMTP id 42EF36B028C for ; Sat, 30 Nov 2019 20:50:36 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id E399640DD for ; Sun, 1 Dec 2019 01:50:35 +0000 (UTC) X-FDA: 76214893230.08.lamp77_52ca8aeb6309 X-HE-Tag: lamp77_52ca8aeb6309 X-Filterd-Recvd-Size: 9369 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Sun, 1 Dec 2019 01:50:35 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2669C208C3; Sun, 1 Dec 2019 01:50:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575165034; bh=y7ntZQuT7q0/JIh2SYpCHrQiJDOQzIO0HD5EFHs+i6U=; h=Date:From:To:Subject:From; b=Cnq+ZFLS5bCQm69f5FPVezdckITKSZVQ8nWSlQih8PtTECSn/nmRVdyP5CHbVyQgC 17spmkjJFxYRtLCXnBDxpKFmWH8GMyZGfkzWgCHta45kuG6STwnT+ZF6hBxtgcRb7V FnQCP1/SPrPqIPBsQmZBvQGrYpShyN3f5afg6D4c= Date: Sat, 30 Nov 2019 17:50:33 -0800 From: akpm@linux-foundation.org To: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, carmenjackson@google.com, dan.j.williams@intel.com, dancol@google.com, ilkos@google.com, jglisse@redhat.com, joel@joelfernandes.org, linux-mm@kvack.org, mayankgupta@google.com, mhocko@suse.com, minchan@kernel.org, mm-commits@vger.kernel.org, pmladek@suse.com, rcampbell@nvidia.com, rostedt@goodmis.org, timmurray@google.com, torvalds@linux-foundation.org, vbabka@suse.cz, willy@infradead.org Subject: [patch 027/158] rss_stat: add support to detect RSS updates of external mm Message-ID: <20191201015033.5BEWpolbT%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: "Joel Fernandes (Google)" Subject: rss_stat: add support to detect RSS updates of external mm When a process updates the RSS of a different process, the rss_stat tracepoint appears in the context of the process doing the update. This can confuse userspace that the RSS of process doing the update is updated, while in reality a different process's RSS was updated. This issue happens in reclaim paths such as with direct reclaim or background reclaim. This patch adds more information to the tracepoint about whether the mm being updated belongs to the current process's context (curr field). We also include a hash of the mm pointer so that the process who the mm belongs to can be uniquely identified (mm_id field). Also vsprintf.c is refactored a bit to allow reuse of hashing code. [akpm@linux-foundation.org: remove unused local `str'] [joelaf@google.com: inline call to ptr_to_hashval] Link: http://lore.kernel.org/r/20191113153816.14b95acd@gandalf.local.home Link: http://lkml.kernel.org/r/20191114164622.GC233237@google.com Link: http://lkml.kernel.org/r/20191106024452.81923-1-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) Reported-by: Ioannis Ilkos Acked-by: Petr Mladek [lib/vsprintf.c] Cc: Tim Murray Cc: Michal Hocko Cc: Carmen Jackson Cc: Mayank Gupta Cc: Daniel Colascione Cc: Steven Rostedt (VMware) Cc: Minchan Kim Cc: "Aneesh Kumar K.V" Cc: Dan Williams Cc: Jerome Glisse Cc: Matthew Wilcox Cc: Ralph Campbell Cc: Vlastimil Babka Cc: Steven Rostedt Signed-off-by: Andrew Morton --- include/linux/mm.h | 8 +++--- include/linux/string.h | 2 + include/trace/events/kmem.h | 32 ++++++++++++++++++++++++--- lib/vsprintf.c | 40 ++++++++++++++++++++++++---------- mm/memory.c | 4 +-- 5 files changed, 66 insertions(+), 20 deletions(-) --- a/include/linux/mm.h~rss_stat-add-support-to-detect-rss-updates-of-external-mm +++ a/include/linux/mm.h @@ -1643,27 +1643,27 @@ static inline unsigned long get_mm_count return (unsigned long)val; } -void mm_trace_rss_stat(int member, long count); +void mm_trace_rss_stat(struct mm_struct *mm, int member, long count); static inline void add_mm_counter(struct mm_struct *mm, int member, long value) { long count = atomic_long_add_return(value, &mm->rss_stat.count[member]); - mm_trace_rss_stat(member, count); + mm_trace_rss_stat(mm, member, count); } static inline void inc_mm_counter(struct mm_struct *mm, int member) { long count = atomic_long_inc_return(&mm->rss_stat.count[member]); - mm_trace_rss_stat(member, count); + mm_trace_rss_stat(mm, member, count); } static inline void dec_mm_counter(struct mm_struct *mm, int member) { long count = atomic_long_dec_return(&mm->rss_stat.count[member]); - mm_trace_rss_stat(member, count); + mm_trace_rss_stat(mm, member, count); } /* Optimized variant when page is already known not to be PageAnon */ --- a/include/linux/string.h~rss_stat-add-support-to-detect-rss-updates-of-external-mm +++ a/include/linux/string.h @@ -216,6 +216,8 @@ int bprintf(u32 *bin_buf, size_t size, c extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, const void *from, size_t available); +int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); + /** * strstarts - does @str start with @prefix? * @str: string to examine --- a/include/trace/events/kmem.h~rss_stat-add-support-to-detect-rss-updates-of-external-mm +++ a/include/trace/events/kmem.h @@ -316,24 +316,50 @@ TRACE_EVENT(mm_page_alloc_extfrag, __entry->change_ownership) ); +/* + * Required for uniquely and securely identifying mm in rss_stat tracepoint. + */ +#ifndef __PTR_TO_HASHVAL +static unsigned int __maybe_unused mm_ptr_to_hash(const void *ptr) +{ + int ret; + unsigned long hashval; + + ret = ptr_to_hashval(ptr, &hashval); + if (ret) + return 0; + + /* The hashed value is only 32-bit */ + return (unsigned int)hashval; +} +#define __PTR_TO_HASHVAL +#endif + TRACE_EVENT(rss_stat, - TP_PROTO(int member, + TP_PROTO(struct mm_struct *mm, + int member, long count), - TP_ARGS(member, count), + TP_ARGS(mm, member, count), TP_STRUCT__entry( + __field(unsigned int, mm_id) + __field(unsigned int, curr) __field(int, member) __field(long, size) ), TP_fast_assign( + __entry->mm_id = mm_ptr_to_hash(mm); + __entry->curr = !!(current->mm == mm); __entry->member = member; __entry->size = (count << PAGE_SHIFT); ), - TP_printk("member=%d size=%ldB", + TP_printk("mm_id=%u curr=%d member=%d size=%ldB", + __entry->mm_id, + __entry->curr, __entry->member, __entry->size) ); --- a/lib/vsprintf.c~rss_stat-add-support-to-detect-rss-updates-of-external-mm +++ a/lib/vsprintf.c @@ -761,11 +761,38 @@ static int __init initialize_ptr_random( early_initcall(initialize_ptr_random); /* Maps a pointer to a 32 bit unique identifier. */ +static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out) +{ + unsigned long hashval; + + if (static_branch_unlikely(¬_filled_random_ptr_key)) + return -EAGAIN; + +#ifdef CONFIG_64BIT + hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); + /* + * Mask off the first 32 bits, this makes explicit that we have + * modified the address (and 32 bits is plenty for a unique ID). + */ + hashval = hashval & 0xffffffff; +#else + hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key); +#endif + *hashval_out = hashval; + return 0; +} + +int ptr_to_hashval(const void *ptr, unsigned long *hashval_out) +{ + return __ptr_to_hashval(ptr, hashval_out); +} + static char *ptr_to_id(char *buf, char *end, const void *ptr, struct printf_spec spec) { const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)"; unsigned long hashval; + int ret; /* When debugging early boot use non-cryptographically secure hash. */ if (unlikely(debug_boot_weak_hash)) { @@ -773,22 +800,13 @@ static char *ptr_to_id(char *buf, char * return pointer_string(buf, end, (const void *)hashval, spec); } - if (static_branch_unlikely(¬_filled_random_ptr_key)) { + ret = __ptr_to_hashval(ptr, &hashval); + if (ret) { spec.field_width = 2 * sizeof(ptr); /* string length must be less than default_width */ return error_string(buf, end, str, spec); } -#ifdef CONFIG_64BIT - hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); - /* - * Mask off the first 32 bits, this makes explicit that we have - * modified the address (and 32 bits is plenty for a unique ID). - */ - hashval = hashval & 0xffffffff; -#else - hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key); -#endif return pointer_string(buf, end, (const void *)hashval, spec); } --- a/mm/memory.c~rss_stat-add-support-to-detect-rss-updates-of-external-mm +++ a/mm/memory.c @@ -154,9 +154,9 @@ static int __init init_zero_pfn(void) } core_initcall(init_zero_pfn); -void mm_trace_rss_stat(int member, long count) +void mm_trace_rss_stat(struct mm_struct *mm, int member, long count) { - trace_rss_stat(member, count); + trace_rss_stat(mm, member, count); } #if defined(SPLIT_RSS_COUNTING) _