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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 9381EC341C5 for ; Fri, 13 Dec 2019 20:53:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE63F2469B for ; Fri, 13 Dec 2019 20:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726802AbfLMUxT (ORCPT ); Fri, 13 Dec 2019 15:53:19 -0500 Received: from mout.kundenserver.de ([212.227.126.134]:46181 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726671AbfLMUxQ (ORCPT ); Fri, 13 Dec 2019 15:53:16 -0500 Received: from threadripper.lan ([149.172.19.189]) by mrelayeu.kundenserver.de (mreue012 [212.227.15.129]) with ESMTPA (Nemesis) id 1MeDYt-1i6oQm1xF1-00bIho; Fri, 13 Dec 2019 21:53:07 +0100 From: Arnd Bergmann To: y2038@lists.linaro.org, linux-kernel@vger.kernel.org Cc: Arnd Bergmann , Al Viro , Richard Fontana , Thomas Gleixner Subject: [PATCH v2 06/24] acct: stop using get_seconds() Date: Fri, 13 Dec 2019 21:52:11 +0100 Message-Id: <20191213205221.3787308-3-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20191213204936.3643476-1-arnd@arndb.de> References: <20191213204936.3643476-1-arnd@arndb.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:st6X4iFmtJPxqaDEnWHJh5aO982P37Ptwn8bOhTHFWKcELag9Vj u9uy/F7aNCOxmXM8GDWXhPfPSVohIQLF/cpqmdRNDJlyjs5FoLkKZXuOl1wSWlYQ+1kjRh1 MXR+HAXY+hf6qeZTKw5iO08MRRwWmloaOTspzIIzU3UYsnTgVrHP72aqgmTNlwyM7j30jQ2 ewbhl+TxIIDPyaymGx+bQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:/P5Nke/yFgs=:XJpZhgz8TDetTezFII4o2+ eXtRcfcirHDAi9Zi9JHrQDJaNR+fsE6lgyR707lukk/IkDM5bdUiibJAQ8wFN2sk1x185EgE5 aCcIicl9JjgSh/3cxoeTedHnNmfg1HeleLIzCjxIYdYjLvquUQ0glGyP5LwcXSoExbYO6mVFE k5kXjzj8TxswNKV/NprsXkAmOdvMes1Rgz3pO19JRyXoMNqziMbjrT341AOaPEXbSC6gUGf8p abvoniCwWC0GkuJYSjw2qu97X5on4kRIS5wWU0dL6v9u9eg+tZWj5NVZz5prgYthgfvZ1yMjH Qe298ynwsh/zQY702mgpyvtXeNkSWK3fE6Fm5xoSfSYpDL2Tm86jGicej116D5fLtske8/c2N qThlrJvEkG/VomPdkDfKgJB7SE9E18ESIoOhHB8chd0fkzMSCF3jTzC4/OKRvC3kLQTp6xkuy p+F3k62RNvB9ErWZq4Ul8Cu3fgdqnoxHT6J9uGyYilnUH8HCDjxYVfz9j2O212z6ouv1yzqIq iT1G4fOMAVL4Pf2abMV4314Xdj/8ZCqa+wNa2okbhe9kfPM2TG3Nd9agKIBIF5IDGQgeJSbH0 bf3F/RlQJ9IGAfWsNOt3X1fbZjlPQqnz7WL3pHPfZgEyCNq6bAEMKQlpJUovkamad/tr3BC+D DsQTqla5WW7KA1bmzTQ7nYz2YWitL+QoR9Ws1azKdiaa0vl4DEVUbXGEMoCDOkMP4VyzzSbYP wLYnd/v1HIBAAgmrdLwXsj9HYxHN6PaZSaC0NXOI1y9HrOUJTCNKeDSOy1MXmBb3HzdrvBIbW BSRYylPiHr0k8ZgJbYFXWRqFac/9Cl0riOhWctfDhLU8LLgOIgGzpCem/gwaLXqQOKHzi5wXc EIJXG1qqpjICfJ6VXKwA== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In 'struct acct', 'struct acct_v3', and 'struct taskstats' we have a 32-bit 'ac_btime' field containing an absolute time value, which will overflow in year 2106. There are two possible ways to deal with it: a) let it overflow and have user space code deal with reconstructing the data based on the current time, or b) truncate the times based on the range of the u32 type. Neither of them solves the actual problem. Pick the second one to best document what the issue is, and have someone fix it in a future version. Signed-off-by: Arnd Bergmann --- include/uapi/linux/acct.h | 2 ++ include/uapi/linux/taskstats.h | 1 + kernel/acct.c | 4 +++- kernel/tsacct.c | 8 +++++--- 4 files changed, 11 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/acct.h b/include/uapi/linux/acct.h index 0e72172cd23a..985b89068591 100644 --- a/include/uapi/linux/acct.h +++ b/include/uapi/linux/acct.h @@ -49,6 +49,7 @@ struct acct __u16 ac_uid16; /* LSB of Real User ID */ __u16 ac_gid16; /* LSB of Real Group ID */ __u16 ac_tty; /* Control Terminal */ + /* __u32 range means times from 1970 to 2106 */ __u32 ac_btime; /* Process Creation Time */ comp_t ac_utime; /* User Time */ comp_t ac_stime; /* System Time */ @@ -81,6 +82,7 @@ struct acct_v3 __u32 ac_gid; /* Real Group ID */ __u32 ac_pid; /* Process ID */ __u32 ac_ppid; /* Parent Process ID */ + /* __u32 range means times from 1970 to 2106 */ __u32 ac_btime; /* Process Creation Time */ #ifdef __KERNEL__ __u32 ac_etime; /* Elapsed Time */ diff --git a/include/uapi/linux/taskstats.h b/include/uapi/linux/taskstats.h index 5e8ca16a9079..7d3ea366e93b 100644 --- a/include/uapi/linux/taskstats.h +++ b/include/uapi/linux/taskstats.h @@ -112,6 +112,7 @@ struct taskstats { __u32 ac_gid; /* Group ID */ __u32 ac_pid; /* Process ID */ __u32 ac_ppid; /* Parent process ID */ + /* __u32 range means times from 1970 to 2106 */ __u32 ac_btime; /* Begin time [sec since 1970] */ __u64 ac_etime __attribute__((aligned(8))); /* Elapsed time [usec] */ diff --git a/kernel/acct.c b/kernel/acct.c index 81f9831a7859..11ff4a596d6b 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -416,6 +416,7 @@ static void fill_ac(acct_t *ac) { struct pacct_struct *pacct = ¤t->signal->pacct; u64 elapsed, run_time; + time64_t btime; struct tty_struct *tty; /* @@ -448,7 +449,8 @@ static void fill_ac(acct_t *ac) } #endif do_div(elapsed, AHZ); - ac->ac_btime = get_seconds() - elapsed; + btime = ktime_get_real_seconds() - elapsed; + ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX); #if ACCT_VERSION==2 ac->ac_ahz = AHZ; #endif diff --git a/kernel/tsacct.c b/kernel/tsacct.c index 7be3e7530841..ab12616ee6fb 100644 --- a/kernel/tsacct.c +++ b/kernel/tsacct.c @@ -24,6 +24,7 @@ void bacct_add_tsk(struct user_namespace *user_ns, const struct cred *tcred; u64 utime, stime, utimescaled, stimescaled; u64 delta; + time64_t btime; BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN); @@ -32,9 +33,10 @@ void bacct_add_tsk(struct user_namespace *user_ns, /* Convert to micro seconds */ do_div(delta, NSEC_PER_USEC); stats->ac_etime = delta; - /* Convert to seconds for btime */ - do_div(delta, USEC_PER_SEC); - stats->ac_btime = get_seconds() - delta; + /* Convert to seconds for btime (note y2106 limit) */ + btime = ktime_get_real_seconds() - div_u64(delta, USEC_PER_SEC); + stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX); + if (thread_group_leader(tsk)) { stats->ac_exitcode = tsk->exit_code; if (tsk->flags & PF_FORKNOEXEC) -- 2.20.0