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Commit 61c34016 authored by James Bottomley's avatar James Bottomley Committed by Kyle McMartin
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[PARISC] Fix do_gettimeofday() hang 



Apparently gettimeoffset can return small negative values (usually in
the 100us range).  If xtime.tv_nsec is accidentally less than this,
though (a fortunately unlikely event) it triggers the loop forever.

I've added a test and correct adjustment for this case.  It has a
warning printk in there which I'd like to leave for the time being
just in case this problem implicates some other part of the kernel.

Signed-off-by: default avatarJames Bottomley <jejb@parisc-linux.org>
Signed-off-by: default avatarKyle McMartin <kyle@parisc-linux.org>
parent 6e1b9585

arch/parisc/kernel/time.c

+16 −2
Original line number Diff line number Diff line
@@ -157,8 +157,22 @@ do_gettimeofday (struct timeval *tv) 
		usec += (xtime.tv_nsec / 1000);

	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));



	while (usec >= 1000000) {

		usec -= 1000000;

	if (unlikely(usec > LONG_MAX)) {

		/* This can happen if the gettimeoffset adjustment is

		 * negative and xtime.tv_nsec is smaller than the

		 * adjustment */

		printk(KERN_ERR "do_gettimeofday() spurious xtime.tv_nsec of %ld\n", usec);

		usec += USEC_PER_SEC;

		--sec;

		/* This should never happen, it means the negative

		 * time adjustment was more than a second, so there's

		 * something seriously wrong */

		BUG_ON(usec > LONG_MAX);

	}





	while (usec >= USEC_PER_SEC) {

		usec -= USEC_PER_SEC;

		++sec;

	}