From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751303AbdJDV4o (ORCPT ); Wed, 4 Oct 2017 17:56:44 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:38844 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120AbdJDV4m (ORCPT ); Wed, 4 Oct 2017 17:56:42 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 2/3] rcutorture: Dump writer stack if stalled Date: Wed, 4 Oct 2017 14:56:35 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20171004215609.GA14782@linux.vnet.ibm.com> References: <20171004215609.GA14782@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17100421-0024-0000-0000-000002DCD37A X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007844; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000233; SDB=6.00926542; UDB=6.00466106; IPR=6.00706754; BA=6.00005620; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017395; XFM=3.00000015; UTC=2017-10-04 21:56:40 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17100421-0025-0000-0000-000045A15739 Message-Id: <1507154196-15100-2-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-04_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710040303 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Right now, rcutorture warns if an rcu_torture_writer() kthread stalls, but this warning is not always all that helpful. This commit therefore makes the first such warning include a stack dump. This in turn requires that sched_show_task() be exported to GPL modules, so this commit makes that change as well. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 6 ++++++ kernel/sched/core.c | 1 + 2 files changed, 7 insertions(+) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 0273bc0a8586..362eb2f78b3c 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -51,6 +51,7 @@ #include #include #include +#include #include "rcu.h" @@ -1240,6 +1241,7 @@ rcu_torture_stats_print(void) long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; static unsigned long rtcv_snap = ULONG_MAX; + static bool splatted; struct task_struct *wtp; for_each_possible_cpu(cpu) { @@ -1325,6 +1327,10 @@ rcu_torture_stats_print(void) gpnum, completed, flags, wtp == NULL ? ~0UL : wtp->state, wtp == NULL ? -1 : (int)task_cpu(wtp)); + if (!splatted && wtp) { + sched_show_task(wtp); + splatted = true; + } show_rcu_gp_kthreads(); rcu_ftrace_dump(DUMP_ALL); } diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d17c5da523a0..7ae0151dcc1d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5165,6 +5165,7 @@ void sched_show_task(struct task_struct *p) show_stack(p, NULL); put_task_stack(p); } +EXPORT_SYMBOL_GPL(sched_show_task); static inline bool state_filter_match(unsigned long state_filter, struct task_struct *p) -- 2.5.2