[PARISC] Fix do_gettimeofday() hang (61c34016) · Commits · 戴 / test

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:

James Bottomley <jejb@parisc-linux.org> Signed-off-by:

Kyle McMartin <kyle@parisc-linux.org>

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;
		}

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