From patchwork Fri Nov 8 21:32:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 178992 Delivered-To: patch@linaro.org Received: by 2002:a92:38d5:0:0:0:0:0 with SMTP id g82csp3313415ilf; Fri, 8 Nov 2019 13:35:53 -0800 (PST) X-Google-Smtp-Source: APXvYqxITLuwS3hUfgUgCJykZKaGFW/x4Bt74P/sG7Ozvwl1ZCpQiTaVKV7sCMJ/aXTVs+MC6Iqk X-Received: by 2002:a17:906:bc9:: with SMTP id y9mr9015080ejg.64.1573248953698; Fri, 08 Nov 2019 13:35:53 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1573248953; cv=none; d=google.com; s=arc-20160816; b=ORSyKijPEmR1xHwwjvzGCIkLFPY/bdWbXNIfLHpMPwDv41lui31ERpVszfffFb2Oe0 ZlyO7TmWxY5pyda5Igf0bi49QiG5OXtZb1Rxid4d5OGamPRsCnOHLiyuy1FNoU4yc6AM HeJ2/7W4agj32RmlsWURSVLUdR3Oi+lmmgGmYMHiAGnmUAWGsX++CIhupOx4gzsW8HIJ MpAP9FdLAhbL2oj2vpZG5W6qSzDr7INeYWfXvZnbhO04MTT3VZSz9axhdtzXTH86uijf gVEqmsvz92uXJLBAcNJA1EjJaRugvn1DtUy73NTCn/0MvIqsWrKp1p29cLa4YHk62snz c7dA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=/EIJXv4Rd5fLnsILTNp7L9ciVJLbLbdXCnfxYhN/HEU=; b=GTHGhuatJhRC4vEhOsVAdiiMkfXYYzqikrzv3uYDiPK6WdluV6oiJf4bcPvJGSaGDO 1fRxrf36gidU2H/BSH6o9FUhFB+F4gIpwk4bT/MnMpHTT16cTfYhWF3ADanGD+mWGSni s1Ua+flgr9LySRusmcuznoVAztWAj3g9CTcoFwcj/7diYV78kbd8WHjeCG7C8AOs9cpS j2WsMnYUCuseETjnOyuseHofMZWbwEF1HR8GE76O4gbqi04pUkZpgBvyN5G7u2QmkbCh 4zFLhmotec5Id9yWoDeGOtcyI/MtTqmW4mqgtQpbd0LbG/YaOmPKCBnp01yRRdOb5UIN YL9w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id v2si5501721ede.61.2019.11.08.13.35.53; Fri, 08 Nov 2019 13:35:53 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387802AbfKHVfv (ORCPT + 26 others); Fri, 8 Nov 2019 16:35:51 -0500 Received: from mout.kundenserver.de ([212.227.126.187]:37887 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387700AbfKHVfv (ORCPT ); Fri, 8 Nov 2019 16:35:51 -0500 Received: from threadripper.lan ([149.172.19.189]) by mrelayeu.kundenserver.de (mreue011 [212.227.15.129]) with ESMTPA (Nemesis) id 1MyK1E-1hheq037vA-00yfkO; Fri, 08 Nov 2019 22:35:40 +0100 From: Arnd Bergmann To: y2038@lists.linaro.org Cc: linux-kernel@vger.kernel.org, Arnd Bergmann , Al Viro , Thomas Gleixner , Richard Fontana Subject: [PATCH 07/16] acct: stop using get_seconds() Date: Fri, 8 Nov 2019 22:32:45 +0100 Message-Id: <20191108213257.3097633-8-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20191108213257.3097633-1-arnd@arndb.de> References: <20191108213257.3097633-1-arnd@arndb.de> MIME-Version: 1.0 X-Provags-ID: V03:K1:MvCmw8KZeUaCp8UqvAYmNhTL2rs0z/UL28/zpU8LBknjj8+U4pP pcYX5LoofEAaw6KYwpc6x17n34w/sKg6L9j6t/L4zZY7B6fKAZcIUpK2mXEKU8Mtbj4Q2de qEnNGj9XgUf9aYvlWbmVmwSRw8O38+8uX8yuBMGU4hHJBR5GtxWSYqgHkPFpXB8gbkFLvcZ QhE0VAW7PqzOU1XQoLp5Q== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1; V03:K0:4RFwLd9Ulic=:rITuPaqqQQO0WKu19dX8Tj Jm7c02EzCGuP2qODrhxkcuhXNv2+4aBeDdZAo7JiVra27cEP9Hmuv7YtlJbIiLsjeUbEFRznA g8TLpWCooqVYSlFnCJerjeLaKicNV1Gu2OixEJ/GARxSKas1KXt+0OSrkQMtH0zC3FH1W5dfz KP8tk56zSUp9hKHChaDeYdZnIeNqdfCMTL6fNOFqcQc0HLofvEo5imk6WDHgjmnsda8LvhDpH APU1qxqtGaIhQ13KNvWNfGPnf//JNE0ypNnraxc16pPQc0rFp0p0sp40M6dnc7ATGxI2tgOLM IW2m+4uqKbX8OzjW1s2Oy2PRkedwtZBOUULXgPZE8QGZt1gRHZSBKvkDkUtWqwnVf8teTdjA7 vat1HR6p1GTIHWniLEMmhBtVCmsOHEXDK6hRXY3IFPInVNfs9CQvxO3uPwvMfinYcwXJevRza 1fCHW3LXFAWGfXiUqHBMG+blCR8T8bGKYlmdBYH1DfdpYctFWXgIwZA5iw6uXjeyvAikAkOxZ z+QeI/N816XcY2gNgQuoM+n0ZANbrSuyBgLqJ8JFgSrZzaSatmEYFd6VjMwMPf8t/zhweL89d Keq4AL/5KVX6aiNLg+dBuDgBQbr55y6tBBnvI4P5urfLwhqyjxUEP9hbx4pEWrjZY4TuqsKnk 7cn1T8pzkv2e10YFZNYA+twYD6mkk46atnArJi3BwNorZuv/0+FI3f6PIU3A0iA9YG+/yixDa mYTbtvuAZir5DhVTF1YxfoSJh4wQgPn/JKEVo1Kr93/7BFIZrClvLomRphRhpRKm7eqLu/XuX 6J++42E3FR02EP8nlHBG8YZ/kh3gNCQNiJsZWa8OMViGYhshwLGQuFrrPD4YmUuX9oE3R/9IK EIfRk5sFTd+jO5CSffig== 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(-) -- 2.20.0 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)