[S390] fix cputime overflow in uptime_proc_show (c3e0ef9a) · Commits · 戴 / test

For 32-bit architectures using standard jiffies the idletime calculation in uptime_proc_show will quickly overflow. It takes (2^32 / HZ) seconds of idle-time, or e.g. 12.45 days with no load on a quad-core with HZ=1000. Switch to 64-bit calculations. Cc: stable@vger.kernel.org Cc: Michael Abbott <michael.abbott@diamond.ac.uk> Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

fs/proc/uptime.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -11,15 +11,20 @@ static int uptime_proc_show(struct seq_file m, void v)
		{
		struct timespec uptime;
		struct timespec idle;
		cputime64_t idletime;
		u64 nsec;
		u32 rem;
		int i;
		cputime_t idletime = 0;

		idletime = 0;
		for_each_possible_cpu(i)
		idletime += kstat_cpu(i).cpustat.idle;

		do_posix_clock_monotonic_gettime(&uptime);
		monotonic_to_bootbased(&uptime);
		cputime_to_timespec(idletime, &idle);
		nsec = cputime64_to_jiffies64(idletime) * TICK_NSEC;
		idle.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
		idle.tv_nsec = rem;
		seq_printf(m, "%lu.%02lu %lu.%02lu\n",
		(unsigned long) uptime.tv_sec,
		(uptime.tv_nsec / (NSEC_PER_SEC / 100)),

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