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Commit 41652937 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Thomas Gleixner
Browse files

hrtimer: fix *rmtp/restarts handling in compat_sys_nanosleep() 



Spotted by Pavel Emelyanov and Alexey Dobriyan.

compat_sys_nanosleep() implicitly uses hrtimer_nanosleep_restart(), this can't
work. Make a suitable compat_nanosleep_restart() helper.

Introduced by commit c70878b4
hrtimer: hook compat_sys_nanosleep up to high res timer code

Also, set ->addr_limit = KERNEL_DS before doing hrtimer_nanosleep(), this func
was changed by the previous patch and now takes the "__user *" parameter.

Thanks to Ingo Molnar for fixing the bug in this patch.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Pavel Emelyanov <xemul@sw.ru>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Toyo Abe <toyoa@mvista.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 080344b9

kernel/compat.c

+40 −4
Original line number Diff line number Diff line
@@ -40,10 +40,36 @@ int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user 
			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;

}



static long compat_nanosleep_restart(struct restart_block *restart)

{

	struct compat_timespec __user *rmtp;

	struct timespec rmt;

	mm_segment_t oldfs;

	long ret;



	rmtp = (struct compat_timespec __user *)(restart->arg1);

	restart->arg1 = (unsigned long)&rmt;

	oldfs = get_fs();

	set_fs(KERNEL_DS);

	ret = hrtimer_nanosleep_restart(restart);

	set_fs(oldfs);



	if (ret) {

		restart->fn = compat_nanosleep_restart;

		restart->arg1 = (unsigned long)rmtp;



		if (rmtp && put_compat_timespec(&rmt, rmtp))

			return -EFAULT;

	}



	return ret;

}



asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,

				     struct compat_timespec __user *rmtp)

{

	struct timespec tu, rmt;

	mm_segment_t oldfs;

	long ret;



	if (get_compat_timespec(&tu, rqtp))
@@ -52,11 +78,21 @@ asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp, 
	if (!timespec_valid(&tu))

		return -EINVAL;



	ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,

				CLOCK_MONOTONIC);

	oldfs = get_fs();

	set_fs(KERNEL_DS);

	ret = hrtimer_nanosleep(&tu,

				rmtp ? (struct timespec __user *)&rmt : NULL,

				HRTIMER_MODE_REL, CLOCK_MONOTONIC);

	set_fs(oldfs);



	if (ret) {

		struct restart_block *restart

			= &current_thread_info()->restart_block;



		restart->fn = compat_nanosleep_restart;

		restart->arg1 = (unsigned long)rmtp;



	if (ret && rmtp) {

		if (put_compat_timespec(&rmt, rmtp))

		if (rmtp && put_compat_timespec(&rmt, rmtp))

			return -EFAULT;

	}