procfs: avoid 32-bit time_t in /proc/*/stat

/proc/stat shows (among lots of other things) the current boottime (i.e.
number of seconds since boot).  While a 32-bit number is sufficient for
this particular case, we want to get rid of the 'struct timespec'
suffers from a 32-bit overflow in 2038.

This changes the code to use a struct timespec64, which is known to be
safe in all cases.

Link: http://lkml.kernel.org/r/20160617201247.2292101-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 510413eb25b8bbff35853232c5b72f0881eaf78c..7907e456ac4f8e8c42091ba74c5415e5397a14db 100644 (file)
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -80,19 +80,17 @@ static u64 get_iowait_time(int cpu)
 static int show_stat(struct seq_file *p, void *v)
 {
        int i, j;
-       unsigned long jif;
        u64 user, nice, system, idle, iowait, irq, softirq, steal;
        u64 guest, guest_nice;
        u64 sum = 0;
        u64 sum_softirq = 0;
        unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
-       struct timespec boottime;
+       struct timespec64 boottime;
 
        user = nice = system = idle = iowait =
                irq = softirq = steal = 0;
        guest = guest_nice = 0;
-       getboottime(&boottime);
-       jif = boottime.tv_sec;
+       getboottime64(&boottime);
 
        for_each_possible_cpu(i) {
                user += kcpustat_cpu(i).cpustat[CPUTIME_USER];
@@ -163,12 +161,12 @@ static int show_stat(struct seq_file *p, void *v)
 
        seq_printf(p,
                "\nctxt %llu\n"
-               "btime %lu\n"
+               "btime %llu\n"
                "processes %lu\n"
                "procs_running %lu\n"
                "procs_blocked %lu\n",
                nr_context_switches(),
-               (unsigned long)jif,
+               (unsigned long long)boottime.tv_sec,
                total_forks,
                nr_running(),
                nr_iowait());