From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, oleg@redhat.com, torvalds@linux-foundation.org
Cc: tglx@linutronix.de, ilya.dryomov@inktank.com,
umgwanakikbuti@gmail.com, linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH 04/11] exit: Deal with nested sleeps
Date: Wed, 24 Sep 2014 10:18:49 +0200 [thread overview]
Message-ID: <20140924082242.186408915@infradead.org> (raw)
In-Reply-To: 20140924081845.572814794@infradead.org
[-- Attachment #1: peterz-might_sleep-exit.patch --]
[-- Type: text/plain, Size: 2625 bytes --]
do_wait() is a big wait loop, but we set TASK_RUNNING too late; we end
up calling potential sleeps before we reset it.
Not strictly a bug since we're guaranteed to exit the loop and not
call schedule(); put in annotations to quiet might_sleep().
WARNING: CPU: 0 PID: 1 at ../kernel/sched/core.c:7123 __might_sleep+0x7e/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8109a788>] do_wait+0x88/0x270
Call Trace:
[<ffffffff81694991>] dump_stack+0x4e/0x7a
[<ffffffff8109877c>] warn_slowpath_common+0x8c/0xc0
[<ffffffff8109886c>] warn_slowpath_fmt+0x4c/0x50
[<ffffffff810bca6e>] __might_sleep+0x7e/0x90
[<ffffffff811a1c15>] might_fault+0x55/0xb0
[<ffffffff8109a3fb>] wait_consider_task+0x90b/0xc10
[<ffffffff8109a804>] do_wait+0x104/0x270
[<ffffffff8109b837>] SyS_wait4+0x77/0x100
[<ffffffff8169d692>] system_call_fastpath+0x16/0x1b
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/kernel.h | 2 ++
kernel/exit.c | 5 +++++
2 files changed, 7 insertions(+)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -175,10 +175,12 @@ extern int _cond_resched(void);
*/
# define might_sleep() \
do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+# define fixup_sleep() __set_current_state(TASK_RUNNING)
#else
static inline void __might_sleep(const char *file, int line,
int preempt_offset) { }
# define might_sleep() do { might_resched(); } while (0)
+# define fixup_sleep() do { } while (0)
#endif
#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -997,6 +997,8 @@ static int wait_task_zombie(struct wait_
get_task_struct(p);
read_unlock(&tasklist_lock);
+ fixup_sleep();
+
if ((exit_code & 0x7f) == 0) {
why = CLD_EXITED;
status = exit_code >> 8;
@@ -1079,6 +1081,7 @@ static int wait_task_zombie(struct wait_
* thread can reap it because we its state == DEAD/TRACE.
*/
read_unlock(&tasklist_lock);
+ fixup_sleep();
retval = wo->wo_rusage
? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
@@ -1210,6 +1213,7 @@ static int wait_task_stopped(struct wait
pid = task_pid_vnr(p);
why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
read_unlock(&tasklist_lock);
+ fixup_sleep();
if (unlikely(wo->wo_flags & WNOWAIT))
return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
@@ -1272,6 +1276,7 @@ static int wait_task_continued(struct wa
pid = task_pid_vnr(p);
get_task_struct(p);
read_unlock(&tasklist_lock);
+ fixup_sleep();
if (!wo->wo_info) {
retval = wo->wo_rusage
next prev parent reply other threads:[~2014-09-24 8:27 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-24 8:18 [PATCH 00/11] nested sleeps, fixes and debug infrastructure Peter Zijlstra
2014-09-24 8:18 ` [PATCH 01/11] locking/mutex: Dont assume TASK_RUNNING Peter Zijlstra
2014-10-28 11:09 ` [tip:sched/core] locking/mutex: Don't " tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 02/11] wait: Provide infrastructure to deal with nested blocking Peter Zijlstra
2014-09-29 21:02 ` Oleg Nesterov
2014-10-02 7:37 ` Peter Zijlstra
2014-10-02 21:21 ` Oleg Nesterov
2014-10-28 11:09 ` [tip:sched/core] sched/wait: " tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 03/11] wait: Add might_sleep() Peter Zijlstra
2014-10-28 11:09 ` [tip:sched/core] sched/wait: Add might_sleep() checks tip-bot for Peter Zijlstra
2014-09-24 8:18 ` Peter Zijlstra [this message]
2014-10-28 11:10 ` [tip:sched/core] sched, exit: Deal with nested sleeps tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 05/11] inotify: " Peter Zijlstra
2014-10-28 11:10 ` [tip:sched/core] sched, " tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 06/11] tty: " Peter Zijlstra
2014-10-28 11:10 ` [tip:sched/core] sched, " tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 07/11] smp: Correctly deal " Peter Zijlstra
2014-10-28 11:11 ` [tip:sched/core] sched, " tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 08/11] module: Fix nested sleep Peter Zijlstra
2014-09-29 22:18 ` Oleg Nesterov
2014-09-30 13:43 ` Peter Zijlstra
2014-10-28 11:11 ` [tip:sched/core] sched, modules: Fix nested sleep in add_unformed_module() tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 09/11] net: Clean up sk_wait_event() vs might_sleep() Peter Zijlstra
2014-09-24 8:36 ` Peter Zijlstra
2014-10-28 11:11 ` [tip:sched/core] sched, net: Clean up sk_wait_event() vs. might_sleep() tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 10/11] sched: Debug nested sleeps Peter Zijlstra
2014-09-29 22:13 ` Oleg Nesterov
2014-09-30 13:49 ` Peter Zijlstra
2014-09-30 21:47 ` Oleg Nesterov
2014-10-01 16:10 ` Peter Zijlstra
2014-10-01 18:35 ` Oleg Nesterov
2014-10-02 9:07 ` Peter Zijlstra
2014-10-02 21:34 ` Oleg Nesterov
2014-10-28 11:11 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2014-09-24 8:18 ` [PATCH 11/11] sched: Exclude cond_resched() from nested sleep test Peter Zijlstra
2014-10-28 11:12 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2014-09-25 8:30 ` [PATCH 00/11] nested sleeps, fixes and debug infrastructure Mike Galbraith
2014-09-25 9:06 ` Peter Zijlstra
2014-09-25 9:10 ` Mike Galbraith
2014-09-25 9:15 ` Peter Zijlstra
2014-09-25 9:56 ` Mike Galbraith
2014-09-25 13:59 ` BUG: sleeping function called from invalid context at drivers/cpufreq/cpufreq.c:370 Mike Galbraith
2014-09-26 6:24 ` Mike Galbraith
2014-09-26 7:54 ` Mike Galbraith
2014-09-26 14:10 ` Rafael J. Wysocki
2014-09-26 22:44 ` Rafael J. Wysocki
2014-09-27 6:14 ` Mike Galbraith
2014-09-27 19:57 ` Rafael J. Wysocki
2014-10-02 10:22 ` [PATCH 00/11] nested sleeps, fixes and debug infrastructure Peter Zijlstra
2014-10-02 12:15 ` Peter Zijlstra
2014-10-27 13:41 ` Peter Zijlstra
2014-10-28 0:07 ` Oleg Nesterov
2014-10-28 8:23 ` Peter Zijlstra
2014-10-29 0:00 ` Oleg Nesterov
2014-10-29 9:35 ` Peter Zijlstra
2014-10-29 11:31 ` Peter Zijlstra
2014-10-29 11:36 ` Peter Zijlstra
2014-10-29 14:26 ` Peter Zijlstra
2014-11-04 16:08 ` [tip:sched/core] audit, sched/wait: Fixup kauditd_thread() wait loop tip-bot for Peter Zijlstra
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