All of lore.kernel.org
 help / color / mirror / Atom feed
From: tip-bot for Peter Zijlstra <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: gregkh@linuxfoundation.org, tglx@linutronix.de, hpa@zytor.com,
	rusty@rustcorp.com.au, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	mingo@kernel.org, fengguang.wu@intel.com, peterz@infradead.org
Subject: [tip:sched/core] sched, modules: Fix nested sleep in add_unformed_module()
Date: Tue, 28 Oct 2014 04:11:24 -0700	[thread overview]
Message-ID: <tip-3c9b2c3d64a49f264422d7743599cf7f6535972d@git.kernel.org> (raw)
In-Reply-To: <20140924082242.458562904@infradead.org>

Commit-ID:  3c9b2c3d64a49f264422d7743599cf7f6535972d
Gitweb:     http://git.kernel.org/tip/3c9b2c3d64a49f264422d7743599cf7f6535972d
Author:     Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 24 Sep 2014 10:18:53 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 28 Oct 2014 10:56:30 +0100

sched, modules: Fix nested sleep in add_unformed_module()

This is a genuine bug in add_unformed_module(), we cannot use blocking
primitives inside a wait loop.

So rewrite the wait_event_interruptible() usage to use the fresh
wait_woken() stuff.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: tglx@linutronix.de
Cc: ilya.dryomov@inktank.com
Cc: umgwanakikbuti@gmail.com
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: oleg@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20140924082242.458562904@infradead.org
[ So this is probably complex to backport and the race wasn't reported AFAIK,
  so not marked for -stable. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/module.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 88cec1d..e52a873 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3097,6 +3097,32 @@ static int may_init_module(void)
 }
 
 /*
+ * Can't use wait_event_interruptible() because our condition
+ * 'finished_loading()' contains a blocking primitive itself (mutex_lock).
+ */
+static int wait_finished_loading(struct module *mod)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	int ret = 0;
+
+	add_wait_queue(&module_wq, &wait);
+	for (;;) {
+		if (finished_loading(mod->name))
+			break;
+
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+
+		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+	}
+	remove_wait_queue(&module_wq, &wait);
+
+	return ret;
+}
+
+/*
  * We try to place it in the list now to make sure it's unique before
  * we dedicate too many resources.  In particular, temporary percpu
  * memory exhaustion.
@@ -3116,8 +3142,8 @@ again:
 		    || old->state == MODULE_STATE_UNFORMED) {
 			/* Wait in case it fails to load. */
 			mutex_unlock(&module_mutex);
-			err = wait_event_interruptible(module_wq,
-					       finished_loading(mod->name));
+
+			err = wait_finished_loading(mod);
 			if (err)
 				goto out_unlocked;
 			goto again;

  parent reply	other threads:[~2014-10-28 11:12 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 ` [PATCH 04/11] exit: Deal with nested sleeps Peter Zijlstra
2014-10-28 11:10   ` [tip:sched/core] sched, " 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-bot for Peter Zijlstra [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=tip-3c9b2c3d64a49f264422d7743599cf7f6535972d@git.kernel.org \
    --to=tipbot@zytor.com \
    --cc=akpm@linux-foundation.org \
    --cc=fengguang.wu@intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=peterz@infradead.org \
    --cc=rusty@rustcorp.com.au \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.