From 4dfc896e90359df04c80da5ab08ec31e87846c43 Mon Sep 17 00:00:00 2001
From: Jiri Kosina <jkosina@suse.cz>
Date: Wed, 28 Mar 2007 18:12:34 +0200
Subject: [PATCH] [PATCH] oprofile: fix potential deadlock on oprofilefs_lock
nmi_cpu_setup() is called from hardirq context and acquires oprofilefs_lock.
alloc_event_buffer() and oprofilefs_ulong_from_user() acquire this lock
without disabling irqs, which could deadlock.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/oprofile/event_buffer.c | 5 +++--
drivers/oprofile/oprofilefs.c | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/oprofile/event_buffer.c b/drivers/oprofile/event_buffer.c
index 00e937e9240e..e7fbac529935 100644
--- a/drivers/oprofile/event_buffer.c
+++ b/drivers/oprofile/event_buffer.c
@@ -70,11 +70,12 @@ void wake_up_buffer_waiter(void)
int alloc_event_buffer(void)
{
int err = -ENOMEM;
+ unsigned long flags;
- spin_lock(&oprofilefs_lock);
+ spin_lock_irqsave(&oprofilefs_lock, flags);
buffer_size = fs_buffer_size;
buffer_watershed = fs_buffer_watershed;
- spin_unlock(&oprofilefs_lock);
+ spin_unlock_irqrestore(&oprofilefs_lock, flags);
if (buffer_watershed >= buffer_size)
return -EINVAL;
diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c
index 6e67b42ca46d..8543cb26cf34 100644
--- a/drivers/oprofile/oprofilefs.c
+++ b/drivers/oprofile/oprofilefs.c
@@ -65,6 +65,7 @@ ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user * buf, size_t co
int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count)
{
char tmpbuf[TMPBUFSIZE];
+ unsigned long flags;
if (!count)
return 0;
@@ -77,9 +78,9 @@ int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, siz
if (copy_from_user(tmpbuf, buf, count))
return -EFAULT;
- spin_lock(&oprofilefs_lock);
+ spin_lock_irqsave(&oprofilefs_lock, flags);
*val = simple_strtoul(tmpbuf, NULL, 0);
- spin_unlock(&oprofilefs_lock);
+ spin_unlock_irqrestore(&oprofilefs_lock, flags);
return 0;
}
--
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