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Commit ac62c5e0 authored by Divya Ojha's avatar Divya Ojha Committed by Banajit Goswami
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drivers: qcom: ultrasound: check concurrent device open operations 



Make opened device count atomic variable to avoid probable race
condition. Race condition leads to memory leak and list corruption.

Change-Id: I4da98f27d36f616bc8fa7b1a848c20cc7eea04e5
Signed-off-by: default avatarDivya Ojha <dojha@codeaurora.org>
parent b8841c42

drivers/misc/qcom/qdsp6v2/ultrasound/usf.c

+4 −7
Original line number Diff line number Diff line
@@ -179,7 +179,7 @@ static const int s_button_map[] = { 
};



/* The opened devices container */

static int s_opened_devs[MAX_DEVS_NUMBER];

static atomic_t s_opened_devs[MAX_DEVS_NUMBER];



static struct wakeup_source usf_wakeup_source;
@@ -2348,14 +2348,11 @@ static uint16_t add_opened_dev(int minor) 
	uint16_t ind = 0;



	for (ind = 0; ind < MAX_DEVS_NUMBER; ++ind) {

		if (minor == s_opened_devs[ind]) {

		if (minor == atomic_cmpxchg(&s_opened_devs[ind], 0, minor)) {

			pr_err("%s: device %d is already opened\n",

			       __func__, minor);

			return USF_UNDEF_DEV_ID;

		}



		if (s_opened_devs[ind] == 0) {

			s_opened_devs[ind] = minor;

		} else {

			pr_debug("%s: device %d is added; ind=%d\n",

				__func__, minor, ind);

			return ind;
@@ -2410,7 +2407,7 @@ static int usf_release(struct inode *inode, struct file *file) 
	usf_disable(&usf->usf_tx);

	usf_disable(&usf->usf_rx);



	s_opened_devs[usf->dev_ind] = 0;

	atomic_set(&s_opened_devs[usf->dev_ind], 0);



	wakeup_source_trash(&usf_wakeup_source);

	mutex_unlock(&usf->mutex);