| From c3e0ef9a298e028a82ada28101ccd5cf64d209ee Mon Sep 17 00:00:00 2001 |
| From: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Date: Thu, 15 Dec 2011 14:56:10 +0100 |
| Subject: [S390] fix cputime overflow in uptime_proc_show |
| |
| From: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| |
| commit c3e0ef9a298e028a82ada28101ccd5cf64d209ee upstream. |
| |
| 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: Michael Abbott <michael.abbott@diamond.ac.uk> |
| Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/proc/uptime.c | 9 +++++++-- |
| 1 file changed, 7 insertions(+), 2 deletions(-) |
| |
| --- a/fs/proc/uptime.c |
| +++ b/fs/proc/uptime.c |
| @@ -11,15 +11,20 @@ static int uptime_proc_show(struct seq_f |
| { |
| struct timespec uptime; |
| struct timespec idle; |
| + cputime64_t idletime; |
| + u64 nsec; |
| + u32 rem; |
| int i; |
| - cputime_t idletime = cputime_zero; |
| |
| + idletime = 0; |
| for_each_possible_cpu(i) |
| idletime = cputime64_add(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)), |
