From: kbuild test robot <lkp@intel.com>
To: Waiman Long <longman@redhat.com>
Cc: kbuild-all@01.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Scott J Norton <scott.norton@hpe.com>,
Waiman Long <longman@redhat.com>
Subject: Re: [PATCH v4 14/20] TP-futex: Support userspace reader/writer locks
Date: Fri, 30 Dec 2016 02:34:59 +0800 [thread overview]
Message-ID: <201612300204.5srRoFC9%fengguang.wu@intel.com> (raw)
In-Reply-To: <1483028026-10305-15-git-send-email-longman@redhat.com>
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Hi Waiman,
[auto build test WARNING on linus/master]
[also build test WARNING on v4.10-rc1 next-20161224]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Waiman-Long/futex-Introducing-throughput-optimized-TP-futexes/20161230-020021
config: i386-randconfig-x006-201652 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
All warnings (new ones prefixed by >>):
kernel/futex.c: In function 'futex_lock':
>> kernel/futex.c:3776:13: warning: 'rspin_timeout' may be used uninitialized in this function [-Wmaybe-uninitialized]
else if (curtime > rspin_timeout)
^
kernel/futex.c:3656:6: note: 'rspin_timeout' was declared here
u64 rspin_timeout;
^~~~~~~~~~~~~
vim +/rspin_timeout +3776 kernel/futex.c
3760
3761 if (!owner_task && (reader_value >= 0)) {
3762 int old_count = reader_value;
3763
3764 /*
3765 * Reset timeout value if the old reader
3766 * count is 0 or the reader value changes and
3767 * handoff time hasn't been reached. Otherwise,
3768 * disable reader spinning if the handoff time
3769 * is reached.
3770 */
3771 reader_value = (uval & FUTEX_TID_MASK);
3772 if (!old_count || (!handoff_set
3773 && (reader_value != old_count)))
3774 rspin_timeout = curtime +
3775 TP_RSPIN_TIMEOUT;
> 3776 else if (curtime > rspin_timeout)
3777 reader_value = -1;
3778 }
3779 if (!handoff_set && (curtime > handoff_time)) {
3780 WARN_ON(READ_ONCE(state->handoff_pid));
3781 WRITE_ONCE(state->handoff_pid, vpid);
3782
3783 /*
3784 * Disable handoff check.
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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next prev parent reply other threads:[~2016-12-29 18:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-29 16:13 [PATCH v4 00/20] futex: Introducing throughput-optimized (TP) futexes Waiman Long
2016-12-29 16:13 ` [PATCH v4 01/20] futex: Consolidate duplicated timer setup code Waiman Long
2016-12-29 16:13 ` [PATCH v4 02/20] futex: Rename futex_pi_state to futex_state Waiman Long
2016-12-29 16:13 ` [PATCH v4 03/20] futex: Add helpers to get & cmpxchg futex value without lock Waiman Long
2016-12-29 16:13 ` [PATCH v4 04/20] futex: Consolidate pure pi_state_list add & delete codes to helpers Waiman Long
2016-12-29 16:13 ` [PATCH v4 05/20] futex: Add a new futex type field into futex_state Waiman Long
2016-12-29 16:13 ` [PATCH v4 06/20] futex: Allow direct attachment of futex_state objects to hash bucket Waiman Long
2016-12-29 16:13 ` [PATCH v4 07/20] futex: Introduce throughput-optimized (TP) futexes Waiman Long
2016-12-29 21:17 ` kbuild test robot
2016-12-29 16:13 ` [PATCH v4 08/20] TP-futex: Enable robust handling Waiman Long
2016-12-29 16:13 ` [PATCH v4 09/20] TP-futex: Implement lock handoff to prevent lock starvation Waiman Long
2016-12-29 16:13 ` [PATCH v4 10/20] TP-futex: Return status code on FUTEX_LOCK calls Waiman Long
2016-12-29 16:13 ` [PATCH v4 11/20] TP-futex: Add timeout support Waiman Long
2016-12-29 16:13 ` [PATCH v4 12/20] TP-futex, doc: Add TP futexes documentation Waiman Long
2016-12-29 16:13 ` [PATCH v4 13/20] perf bench: New microbenchmark for userspace mutex performance Waiman Long
2017-01-02 17:16 ` Arnaldo Carvalho de Melo
2017-01-02 18:17 ` Waiman Long
2016-12-29 16:13 ` [PATCH v4 14/20] TP-futex: Support userspace reader/writer locks Waiman Long
2016-12-29 18:34 ` kbuild test robot [this message]
2016-12-29 16:13 ` [PATCH v4 15/20] TP-futex: Enable kernel reader lock stealing Waiman Long
2016-12-29 16:13 ` [PATCH v4 16/20] TP-futex: Group readers together in wait queue Waiman Long
2016-12-29 19:53 ` kbuild test robot
2016-12-29 20:16 ` kbuild test robot
2016-12-29 16:13 ` [PATCH v4 17/20] TP-futex, doc: Update TP futexes document on shared locking Waiman Long
2016-12-29 16:13 ` [PATCH v4 18/20] perf bench: New microbenchmark for userspace rwlock performance Waiman Long
2016-12-29 16:13 ` [PATCH v4 19/20] sched, TP-futex: Make wake_up_q() return wakeup count Waiman Long
2016-12-29 16:13 ` [PATCH v4 20/20] futex: Dump internal futex state via debugfs Waiman Long
2016-12-29 18:55 ` kbuild test robot
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