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[PATCH] oprofile: fix potential deadlock on oprofilefs_lock

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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>
This commit is contained in:
Jiri Kosina 2007-03-28 18:12:34 +02:00 • committed by Linus Torvalds
parent 6faee84b00
commit 4dfc896e90
2 changed files with 6 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

5
drivers/oprofile/event_buffer.c
View file

@ -70,11 +70,12 @@ void wake_up_buffer_waiter(void)
int alloc_event_buffer(void) int alloc_event_buffer(void)
{ {
int err = -ENOMEM; int err = -ENOMEM;
unsigned long flags;
spin_lock(&oprofilefs_lock); spin_lock_irqsave(&oprofilefs_lock, flags);
buffer_size = fs_buffer_size; buffer_size = fs_buffer_size;
buffer_watershed = fs_buffer_watershed; buffer_watershed = fs_buffer_watershed;
spin_unlock(&oprofilefs_lock); spin_unlock_irqrestore(&oprofilefs_lock, flags);
if (buffer_watershed >= buffer_size) if (buffer_watershed >= buffer_size)
return -EINVAL; return -EINVAL;

5
drivers/oprofile/oprofilefs.c
View file

@ -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) int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count)
{ {
char tmpbuf[TMPBUFSIZE]; char tmpbuf[TMPBUFSIZE];
unsigned long flags;
if (!count) if (!count)
return 0; 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)) if (copy_from_user(tmpbuf, buf, count))
return -EFAULT; return -EFAULT;
spin_lock(&oprofilefs_lock); spin_lock_irqsave(&oprofilefs_lock, flags);
*val = simple_strtoul(tmpbuf, NULL, 0); *val = simple_strtoul(tmpbuf, NULL, 0);
spin_unlock(&oprofilefs_lock); spin_unlock_irqrestore(&oprofilefs_lock, flags);
return 0; return 0;
} }