From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Julia Cartwright <julia@ni.com>,
Daniel Wagner <daniel.wagner@siemens.com>,
tom.zanussi@linux.intel.com, Alex Shi <alex.shi@linaro.org>
Subject: [PATCH RT 03/10] random: avoid preempt_disable()ed section
Date: Thu, 23 Nov 2017 00:33:44 -0500 [thread overview]
Message-ID: <20171123053433.594374450@goodmis.org> (raw)
In-Reply-To: 20171123053341.174002403@goodmis.org
[-- Attachment #1: 0003-random-avoid-preempt_disable-ed-section.patch --]
[-- Type: text/plain, Size: 2160 bytes --]
4.4.97-rt111-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
extract_crng() will use sleeping locks while in a preempt_disable()
section due to get_cpu_var().
Work around it with local_locks.
Cc: stable-rt@vger.kernel.org # where it applies to
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
drivers/char/random.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index fecc40a69df8..b41745c5962c 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -260,6 +260,7 @@
#include <linux/irq.h>
#include <linux/syscalls.h>
#include <linux/completion.h>
+#include <linux/locallock.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
@@ -1796,6 +1797,7 @@ int random_int_secret_init(void)
static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash)
__aligned(sizeof(unsigned long));
+static DEFINE_LOCAL_IRQ_LOCK(hash_entropy_int_lock);
/*
* Get a random word for internal kernel use only. Similar to urandom but
@@ -1811,12 +1813,12 @@ unsigned int get_random_int(void)
if (arch_get_random_int(&ret))
return ret;
- hash = get_cpu_var(get_random_int_hash);
+ hash = &get_locked_var(hash_entropy_int_lock, get_random_int_hash);
hash[0] += current->pid + jiffies + random_get_entropy();
md5_transform(hash, random_int_secret);
ret = hash[0];
- put_cpu_var(get_random_int_hash);
+ put_locked_var(hash_entropy_int_lock, get_random_int_hash);
return ret;
}
@@ -1833,12 +1835,12 @@ unsigned long get_random_long(void)
if (arch_get_random_long(&ret))
return ret;
- hash = get_cpu_var(get_random_int_hash);
+ hash = &get_locked_var(hash_entropy_int_lock, get_random_int_hash);
hash[0] += current->pid + jiffies + random_get_entropy();
md5_transform(hash, random_int_secret);
ret = *(unsigned long *)hash;
- put_cpu_var(get_random_int_hash);
+ put_locked_var(hash_entropy_int_lock, get_random_int_hash);
return ret;
}
--
2.13.2
next prev parent reply other threads:[~2017-11-23 5:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-23 5:33 [PATCH RT 00/10] Linux 4.4.97-rt111-rc2 Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 01/10] timer/hrtimer: check properly for a running timer Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 02/10] rtmutex: Make lock_killable work Steven Rostedt
2017-11-23 5:33 ` Steven Rostedt [this message]
2017-11-24 6:26 ` [PATCH RT 03/10] random: avoid preempt_disable()ed section Alex Shi
2017-11-28 2:18 ` Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 04/10] sched: Prevent task state corruption by spurious lock wakeup Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 05/10] sched: Remove TASK_ALL Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 06/10] sched/migrate disable: handle updated task-mask mg-dis section Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 08/10] fs: convert two more BH_Uptodate_Lock related bitspinlocks Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 09/10] md/raid5: do not disable interrupts Steven Rostedt
2017-11-23 5:33 ` [PATCH RT 10/10] Linux 4.4.97-rt111-rc2 Steven Rostedt
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