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Commit c3484c27 authored by Richard Cochran's avatar Richard Cochran Committed by David S. Miller
Browse files

ptp: reduce stack usage when measuring the system time offset 



This patch removes the large buffer from the stack of the system
offset ioctl and replaces it with a kmalloced buffer.

Signed-off-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c7ec0bad

drivers/ptp/ptp_chardev.c

+14 −7
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) 
{

	struct ptp_clock_caps caps;

	struct ptp_clock_request req;

	struct ptp_sys_offset sysoff;

	struct ptp_sys_offset *sysoff = NULL;

	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);

	struct ptp_clock_info *ops = ptp->info;

	struct ptp_clock_time *pct;
@@ -94,17 +94,22 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) 
		break;



	case PTP_SYS_OFFSET:

		if (copy_from_user(&sysoff, (void __user *)arg,

				   sizeof(sysoff))) {

		sysoff = kmalloc(sizeof(*sysoff), GFP_KERNEL);

		if (!sysoff) {

			err = -ENOMEM;

			break;

		}

		if (copy_from_user(sysoff, (void __user *)arg,

				   sizeof(*sysoff))) {

			err = -EFAULT;

			break;

		}

		if (sysoff.n_samples > PTP_MAX_SAMPLES) {

		if (sysoff->n_samples > PTP_MAX_SAMPLES) {

			err = -EINVAL;

			break;

		}

		pct = &sysoff.ts[0];

		for (i = 0; i < sysoff.n_samples; i++) {

		pct = &sysoff->ts[0];

		for (i = 0; i < sysoff->n_samples; i++) {

			getnstimeofday(&ts);

			pct->sec = ts.tv_sec;

			pct->nsec = ts.tv_nsec;
@@ -117,7 +122,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) 
		getnstimeofday(&ts);

		pct->sec = ts.tv_sec;

		pct->nsec = ts.tv_nsec;

		if (copy_to_user((void __user *)arg, &sysoff, sizeof(sysoff)))

		if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))

			err = -EFAULT;

		break;
@@ -125,6 +130,8 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) 
		err = -ENOTTY;

		break;

	}



	kfree(sysoff);

	return err;

}