The blktrace code stores the current time in a 32-bit word in its
user interface. This is a bad idea because 32-bit seconds overflow
at some point.
We probably have until 2106 before this one overflows, as it seems
to use an 'unsigned' variable, but we should confirm that user
space treats it the same way.
Aside from this, we want to stop using 'struct timespec' here,
so I'm adding a comment about the overflow and change the code
to use timespec64 instead to make the loss of range more obvious.
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
---
kernel/trace/blktrace.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index ef86b965ade3..b0816e4a61a5 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -127,12 +127,13 @@ static void trace_note_tsk(struct task_struct *tsk)
static void trace_note_time(struct blk_trace *bt)
{
- struct timespec now;
+ struct timespec64 now;
unsigned long flags;
u32 words[2];
- getnstimeofday(&now);
- words[0] = now.tv_sec;
+ /* need to check user space to see if this breaks in y2038 or y2106 */
+ ktime_get_real_ts64(&now);
+ words[0] = (u32)now.tv_sec;
words[1] = now.tv_nsec;
local_irq_save(flags);
--
2.9.0
The conversion to the 64-bit time based ptp methods left two instances
of 'struct timespec' in place. This is harmless because 64-bit
architectures define timespec64 as timespec, and this driver is
not used on 32-bit machines.
However, using 'struct timespec64' directly is obviously the right
thing to do, and will help us remove 'struct timespec' in the future.
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
Fixes: b9acf24f779c ("ptp: tilegx: convert to the 64 bit get/set time methods.")
---
drivers/net/ethernet/tile/tilegx.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c
index 0a15acc075b3..11213a38c795 100644
--- a/drivers/net/ethernet/tile/tilegx.c
+++ b/drivers/net/ethernet/tile/tilegx.c
@@ -462,7 +462,7 @@ static void tile_tx_timestamp(struct sk_buff *skb, int instance)
if (unlikely((shtx->tx_flags & SKBTX_HW_TSTAMP) != 0)) {
struct mpipe_data *md = &mpipe_data[instance];
struct skb_shared_hwtstamps shhwtstamps;
- struct timespec ts;
+ struct timespec64 ts;
shtx->tx_flags |= SKBTX_IN_PROGRESS;
gxio_mpipe_get_timestamp(&md->context, &ts);
@@ -886,9 +886,9 @@ static struct ptp_clock_info ptp_mpipe_caps = {
/* Sync mPIPE's timestamp up with Linux system time and register PTP clock. */
static void register_ptp_clock(struct net_device *dev, struct mpipe_data *md)
{
- struct timespec ts;
+ struct timespec64 ts;
- getnstimeofday(&ts);
+ ktime_get_ts64(&ts);
gxio_mpipe_set_timestamp(&md->context, &ts);
mutex_init(&md->ptp_lock);
--
2.9.0
The sequencer client manager reports timestamps in units of unsigned
32-bit seconds/nanoseconds, but that does not suffer from the y2038
overflow because it stores only the delta since the 'last_update'
time was recorded.
However, the use of the do_gettimeofday() function is problematic
and we have to replace it to avoid the overflow on on 32-bit
architectures.
This uses 'struct timespec64' to record 'last_update', and changes
the code to use monotonic timestamps that do not suffer from leap
seconds and settimeofday updates.
As a side-effect, the code can now use the timespec64_sub() helper
and become more readable and also avoid a multiplication to convert
from microseconds to nanoseconds.
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
---
sound/core/seq/seq_timer.c | 23 +++++++++--------------
sound/core/seq/seq_timer.h | 2 +-
2 files changed, 10 insertions(+), 15 deletions(-)
diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c
index 293104926098..dcc102813aef 100644
--- a/sound/core/seq/seq_timer.c
+++ b/sound/core/seq/seq_timer.c
@@ -165,7 +165,7 @@ static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
snd_seq_timer_update_tick(&tmr->tick, resolution);
/* register actual time of this timer update */
- do_gettimeofday(&tmr->last_update);
+ ktime_get_ts64(&tmr->last_update);
spin_unlock_irqrestore(&tmr->lock, flags);
@@ -392,7 +392,7 @@ static int seq_timer_start(struct snd_seq_timer *tmr)
return -EINVAL;
snd_timer_start(tmr->timeri, tmr->ticks);
tmr->running = 1;
- do_gettimeofday(&tmr->last_update);
+ ktime_get_ts64(&tmr->last_update);
return 0;
}
@@ -420,7 +420,7 @@ static int seq_timer_continue(struct snd_seq_timer *tmr)
}
snd_timer_start(tmr->timeri, tmr->ticks);
tmr->running = 1;
- do_gettimeofday(&tmr->last_update);
+ ktime_get_ts64(&tmr->last_update);
return 0;
}
@@ -444,17 +444,12 @@ snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr)
spin_lock_irqsave(&tmr->lock, flags);
cur_time = tmr->cur_time;
if (tmr->running) {
- struct timeval tm;
- int usec;
- do_gettimeofday(&tm);
- usec = (int)(tm.tv_usec - tmr->last_update.tv_usec);
- if (usec < 0) {
- cur_time.tv_nsec += (1000000 + usec) * 1000;
- cur_time.tv_sec += tm.tv_sec - tmr->last_update.tv_sec - 1;
- } else {
- cur_time.tv_nsec += usec * 1000;
- cur_time.tv_sec += tm.tv_sec - tmr->last_update.tv_sec;
- }
+ struct timespec64 tm;
+
+ ktime_get_ts64(&tm);
+ tm = timespec64_sub(tm, tmr->last_update);
+ cur_time.tv_nsec = tm.tv_nsec;
+ cur_time.tv_sec = tm.tv_sec;
snd_seq_sanity_real_time(&cur_time);
}
spin_unlock_irqrestore(&tmr->lock, flags);
diff --git a/sound/core/seq/seq_timer.h b/sound/core/seq/seq_timer.h
index 88dfb71805ae..9506b661fe5b 100644
--- a/sound/core/seq/seq_timer.h
+++ b/sound/core/seq/seq_timer.h
@@ -52,7 +52,7 @@ struct snd_seq_timer {
unsigned int skew;
unsigned int skew_base;
- struct timeval last_update; /* time of last clock update, used for interpolation */
+ struct timespec64 last_update; /* time of last clock update, used for interpolation */
spinlock_t lock;
};
--
2.9.0
/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.
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
---
fs/proc/stat.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 510413eb25b8..7907e456ac4f 100644
--- 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());
--
2.9.0