From: kosaki.motohiro@gmail.com
To: linux-kernel@vger.kernel.org
Cc: Olivier Langlois <olivier@trillion01.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>,
David Miller <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
a.p.zijlstra@chello.nl, paulus@samba.org,
acme@ghostprotocols.net
Subject: [PATCH 01/10] events: Protect access via task_subsys_state_check()
Date: Mon, 29 Apr 2013 23:17:09 -0400 [thread overview]
Message-ID: <1367291838-5490-2-git-send-email-kosaki.motohiro@gmail.com> (raw)
In-Reply-To: <1367291838-5490-1-git-send-email-kosaki.motohiro@gmail.com>
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The following RCU splat indicates lack of RCU protection:
[ 953.267649] ===============================
[ 953.267652] [ INFO: suspicious RCU usage. ]
[ 953.267657] 3.9.0-0.rc6.git2.4.fc19.ppc64p7 #1 Not tainted
[ 953.267661] -------------------------------
[ 953.267664] include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage!
[ 953.267669]
[ 953.267669] other info that might help us debug this:
[ 953.267669]
[ 953.267675]
[ 953.267675] rcu_scheduler_active = 1, debug_locks = 0
[ 953.267680] 1 lock held by glxgears/1289:
[ 953.267683] #0: (&sig->cred_guard_mutex){+.+.+.}, at: [<c00000000027f884>] .prepare_bprm_creds+0x34/0xa0
[ 953.267700]
[ 953.267700] stack backtrace:
[ 953.267704] Call Trace:
[ 953.267709] [c0000001f0d1b6e0] [c000000000016e30] .show_stack+0x130/0x200 (unreliable)
[ 953.267717] [c0000001f0d1b7b0] [c0000000001267f8] .lockdep_rcu_suspicious+0x138/0x180
[ 953.267724] [c0000001f0d1b840] [c0000000001d43a4] .perf_event_comm+0x4c4/0x690
[ 953.267731] [c0000001f0d1b950] [c00000000027f6e4] .set_task_comm+0x84/0x1f0
[ 953.267737] [c0000001f0d1b9f0] [c000000000280414] .setup_new_exec+0x94/0x220
[ 953.267744] [c0000001f0d1ba70] [c0000000002f665c] .load_elf_binary+0x58c/0x19b0
...
This commit therefore adds the required RCU read-side critical
section to perf_event_comm().
Reported-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Link: http://lkml.kernel.org/r/20130419190124.GA8638@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Gustavo Luiz Duarte <gusld@br.ibm.com>
---
kernel/events/core.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4d3124b..9fcb094 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4596,6 +4596,7 @@ void perf_event_comm(struct task_struct *task)
struct perf_event_context *ctx;
int ctxn;
+ rcu_read_lock();
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (!ctx)
@@ -4603,6 +4604,7 @@ void perf_event_comm(struct task_struct *task)
perf_event_enable_on_exec(ctx);
}
+ rcu_read_unlock();
if (!atomic_read(&nr_comm_events))
return;
--
1.7.1
next prev parent reply other threads:[~2013-04-30 3:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-30 3:17 [PATCH v3 0/7] posix-cpu-timers fixlet kosaki.motohiro
2013-04-30 3:17 ` kosaki.motohiro [this message]
2013-04-30 3:17 ` [PATCH 02/10] vm: add no-mmu vm_iomap_memory() stub kosaki.motohiro
2013-04-30 3:17 ` [PATCH 03/10] ARM: OMAP4: hwmod data: make 'ocp2scp_usb_phy_phy_48m" as the main clock kosaki.motohiro
2013-04-30 3:17 ` [PATCH 04/10] posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting kosaki.motohiro
2013-04-30 3:38 ` KOSAKI Motohiro
2013-04-30 3:17 ` [PATCH 05/10] posix-cpu-timers: fix acounting delta_exec twice kosaki.motohiro
2013-04-30 3:17 ` [PATCH 06/10] posix-cpu-timers: fix wrong timer initialization kosaki.motohiro
2013-04-30 13:34 ` Olivier Langlois
2013-04-30 3:17 ` [PATCH 07/10] posix-cpu-timers: timer functions must use timer time instead of clock time kosaki.motohiro
2013-04-30 3:17 ` [PATCH 08/10] posix-cpu-timers: check_thread_timers() uses task_sched_runtime() kosaki.motohiro
2013-04-30 3:17 ` [PATCH 09/10] sched: task_sched_runtime introduce micro optimization kosaki.motohiro
2013-05-01 11:00 ` Peter Zijlstra
2013-05-01 11:50 ` Paul Turner
2013-05-01 18:55 ` KOSAKI Motohiro
2013-05-01 18:42 ` KOSAKI Motohiro
2013-04-30 3:17 ` [PATCH 10/10] posix-cpu-timers: cleanup cpu_{clock,timer}_sample{,_group} kosaki.motohiro
2013-05-01 11:01 ` [PATCH v3 0/7] posix-cpu-timers fixlet Peter Zijlstra
2013-05-01 18:45 ` KOSAKI Motohiro
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