Messages in this thread Patch in this message | | | Date | Mon, 3 Jun 2013 15:34:57 +0200 | Subject | [PATCH] timekeeping: handle epoch roll-over (2038) on 32-bit systems | From | Tobias Waldekranz <> |
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In ktime_get_update_offsets, calculate the current time in the same way as in ktime_get.
On 32-bit systems, the current time is truncated via the call to ktime_set, the following subtraction of offs_real will result in an inaccurate time when the current number of seconds since epoch can no longer fit in 31-bits (2038-01-19 03:14:07 UTC). This will send hrtimer_interrupt into an infinite loop on some architectures (arm), or emit an oops on others(x86).
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> --- kernel/time/timekeeping.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 98cd470..b484ab2 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1600,8 +1600,8 @@ ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot, do { seq = read_seqcount_begin(&timekeeper_seq);
- secs = tk->xtime_sec; - nsecs = timekeeping_get_ns(tk); + secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; + nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec;
*offs_real = tk->offs_real; *offs_boot = tk->offs_boot; @@ -1609,7 +1609,6 @@ ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot, } while (read_seqcount_retry(&timekeeper_seq, seq));
now = ktime_add_ns(ktime_set(secs, 0), nsecs); - now = ktime_sub(now, *offs_real); return now; } #endif -- 1.7.10.4
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