From 2d602bf28316e2f61a553f13d279f3d74c2e5189 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 24 Oct 2019 16:34:25 +0200 Subject: acct: stop using get_seconds() In 'struct acct', 'struct acct_v3', and 'struct taskstats' we have a 32-bit 'ac_btime' field containing an absolute time value, which will overflow in year 2106. There are two possible ways to deal with it: a) let it overflow and have user space code deal with reconstructing the data based on the current time, or b) truncate the times based on the range of the u32 type. Neither of them solves the actual problem. Pick the second one to best document what the issue is, and have someone fix it in a future version. Signed-off-by: Arnd Bergmann --- kernel/acct.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/acct.c') diff --git a/kernel/acct.c b/kernel/acct.c index 81f9831a7859..11ff4a596d6b 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -416,6 +416,7 @@ static void fill_ac(acct_t *ac) { struct pacct_struct *pacct = ¤t->signal->pacct; u64 elapsed, run_time; + time64_t btime; struct tty_struct *tty; /* @@ -448,7 +449,8 @@ static void fill_ac(acct_t *ac) } #endif do_div(elapsed, AHZ); - ac->ac_btime = get_seconds() - elapsed; + btime = ktime_get_real_seconds() - elapsed; + ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX); #if ACCT_VERSION==2 ac->ac_ahz = AHZ; #endif -- cgit v1.2.3