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Commit 51abf45c authored by Salah Triki's avatar Salah Triki Committed by Greg Kroah-Hartman
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staging: dgnc: take a lock when storing value in dgnc_poll_tick 



Reads of dgnc_poll_tick are protected by dgnc_poll_lock spinlock, but the write
to dgnc_poll_tick is not. It could theoretically race.

Signed-off-by: default avatarSalah Triki <salah.triki@acm.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6d99d6a3

drivers/staging/dgnc/dgnc_driver.c

+1 −1
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ static const struct file_operations dgnc_BoardFops = { 
uint			dgnc_NumBoards;

struct dgnc_board		*dgnc_Board[MAXBOARDS];

DEFINE_SPINLOCK(dgnc_global_lock);

DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */

uint			dgnc_Major;

int			dgnc_poll_tick = 20;	/* Poll interval - 20 ms */
@@ -74,7 +75,6 @@ static struct class *dgnc_class; 
/*

 * Poller stuff

 */

static DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */

static ulong		dgnc_poll_time; /* Time of next poll */

static uint		dgnc_poll_stop; /* Used to tell poller to stop */

static struct timer_list dgnc_poll_timer;

drivers/staging/dgnc/dgnc_driver.h

+1 −0
Original line number Diff line number Diff line
@@ -390,6 +390,7 @@ struct channel_t { 
extern uint		dgnc_Major;		/* Our driver/mgmt major */

extern int		dgnc_poll_tick;		/* Poll interval - 20 ms */

extern spinlock_t	dgnc_global_lock;	/* Driver global spinlock */

extern spinlock_t	dgnc_poll_lock;		/* Poll scheduling lock */

extern uint		dgnc_NumBoards;		/* Total number of boards */

extern struct dgnc_board	*dgnc_Board[MAXBOARDS];	/* Array of board structs */

drivers/staging/dgnc/dgnc_sysfs.c

+8 −1
Original line number Diff line number Diff line
@@ -56,11 +56,18 @@ static ssize_t dgnc_driver_pollrate_show(struct device_driver *ddp, char *buf) 
static ssize_t dgnc_driver_pollrate_store(struct device_driver *ddp,

					  const char *buf, size_t count)

{

	unsigned long flags;

	int tick;

	int ret;



	ret = sscanf(buf, "%d\n", &dgnc_poll_tick);

	ret = sscanf(buf, "%d\n", &tick);

	if (ret != 1)

		return -EINVAL;



	spin_lock_irqsave(&dgnc_poll_lock, flags);

	dgnc_poll_tick = tick;

	spin_unlock_irqrestore(&dgnc_poll_lock, flags);



	return count;

}

static DRIVER_ATTR(pollrate, (S_IRUSR | S_IWUSR), dgnc_driver_pollrate_show,