Message ID | 1442332148-488079-2-git-send-email-arnd@arndb.de (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Hello Arnd, On 15.09.2015 17:49, Arnd Bergmann wrote: > The dvb demuxer code uses a 'struct timespec' to pass a timeout > as absolute time. This will cause problems on 32-bit architectures > in 2038 when time_t overflows, and it is racy with a concurrent > settimeofday() call. > > This patch changes the code to use ktime_get() instead, using > the monotonic time base to avoid both the race and the overflow. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/media/dvb-core/demux.h | 2 +- > drivers/media/dvb-core/dmxdev.c | 2 +- > drivers/media/dvb-core/dvb_demux.c | 17 ++++++----------- > drivers/media/dvb-core/dvb_demux.h | 4 ++-- > drivers/media/dvb-core/dvb_net.c | 2 +- > 5 files changed, 11 insertions(+), 16 deletions(-) > > diff --git a/drivers/media/dvb-core/demux.h b/drivers/media/dvb-core/demux.h > index 833191bcd810..d8e2b1213bef 100644 > --- a/drivers/media/dvb-core/demux.h > +++ b/drivers/media/dvb-core/demux.h > @@ -92,7 +92,7 @@ struct dmx_ts_feed { > int type, > enum dmx_ts_pes pes_type, > size_t circular_buffer_size, > - struct timespec timeout); > + ktime_t timeout); > int (*start_filtering) (struct dmx_ts_feed* feed); > int (*stop_filtering) (struct dmx_ts_feed* feed); > }; > diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c > index d0e3f9d85f34..0d20b379eeec 100644 > --- a/drivers/media/dvb-core/dmxdev.c > +++ b/drivers/media/dvb-core/dmxdev.c > @@ -558,7 +558,7 @@ static int dvb_dmxdev_start_feed(struct dmxdev *dmxdev, > struct dmxdev_filter *filter, > struct dmxdev_feed *feed) > { > - struct timespec timeout = { 0 }; > + ktime_t timeout = ktime_set(0, 0); > struct dmx_pes_filter_params *para = &filter->params.pes; > dmx_output_t otype; > int ret; > diff --git a/drivers/media/dvb-core/dvb_demux.c b/drivers/media/dvb-core/dvb_demux.c > index 6c7ff0cdcd32..d83dd0eb5757 100644 > --- a/drivers/media/dvb-core/dvb_demux.c > +++ b/drivers/media/dvb-core/dvb_demux.c > @@ -399,28 +399,23 @@ static void dvb_dmx_swfilter_packet(struct dvb_demux *demux, const u8 *buf) > int dvr_done = 0; > > if (dvb_demux_speedcheck) { > - struct timespec cur_time, delta_time; > + ktime_t cur_time; > u64 speed_bytes, speed_timedelta; > > demux->speed_pkts_cnt++; > > /* show speed every SPEED_PKTS_INTERVAL packets */ > if (!(demux->speed_pkts_cnt % SPEED_PKTS_INTERVAL)) { > - cur_time = current_kernel_time(); > + cur_time = ktime_get(); > > - if (demux->speed_last_time.tv_sec != 0 && > - demux->speed_last_time.tv_nsec != 0) { > - delta_time = timespec_sub(cur_time, > - demux->speed_last_time); > + if (ktime_to_ns(demux->speed_last_time) == 0) { if ktime_to_ns does what I think it does, then you should invert the logic. Regards, Andreas > speed_bytes = (u64)demux->speed_pkts_cnt > * 188 * 8; > /* convert to 1024 basis */ > speed_bytes = 1000 * div64_u64(speed_bytes, > 1024); > - speed_timedelta = > - (u64)timespec_to_ns(&delta_time); > - speed_timedelta = div64_u64(speed_timedelta, > - 1000000); /* nsec -> usec */ > + speed_timedelta = ktime_ms_delta(cur_time, > + demux->speed_last_time); > printk(KERN_INFO "TS speed %llu Kbits/sec \n", > div64_u64(speed_bytes, > speed_timedelta)); > @@ -667,7 +662,7 @@ out: > > static int dmx_ts_feed_set(struct dmx_ts_feed *ts_feed, u16 pid, int ts_type, > enum dmx_ts_pes pes_type, > - size_t circular_buffer_size, struct timespec timeout) > + size_t circular_buffer_size, ktime_t timeout) > { > struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed; > struct dvb_demux *demux = feed->demux; > diff --git a/drivers/media/dvb-core/dvb_demux.h b/drivers/media/dvb-core/dvb_demux.h > index ae7fc33c3231..5ed3cab4ad28 100644 > --- a/drivers/media/dvb-core/dvb_demux.h > +++ b/drivers/media/dvb-core/dvb_demux.h > @@ -83,7 +83,7 @@ struct dvb_demux_feed { > u8 *buffer; > int buffer_size; > > - struct timespec timeout; > + ktime_t timeout; > struct dvb_demux_filter *filter; > > int ts_type; > @@ -134,7 +134,7 @@ struct dvb_demux { > > uint8_t *cnt_storage; /* for TS continuity check */ > > - struct timespec speed_last_time; /* for TS speed check */ > + ktime_t speed_last_time; /* for TS speed check */ > uint32_t speed_pkts_cnt; /* for TS speed check */ > }; > > diff --git a/drivers/media/dvb-core/dvb_net.c b/drivers/media/dvb-core/dvb_net.c > index b81e026edab3..df3ba15c007e 100644 > --- a/drivers/media/dvb-core/dvb_net.c > +++ b/drivers/media/dvb-core/dvb_net.c > @@ -998,7 +998,7 @@ static int dvb_net_feed_start(struct net_device *dev) > netdev_dbg(dev, "start filtering\n"); > priv->secfeed->start_filtering(priv->secfeed); > } else if (priv->feedtype == DVB_NET_FEEDTYPE_ULE) { > - struct timespec timeout = { 0, 10000000 }; // 10 msec > + ktime_t timeout = ns_to_ktime(10 * NSEC_PER_MSEC); > > /* we have payloads encapsulated in TS */ > netdev_dbg(dev, "alloc tsfeed\n"); > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday 15 September 2015 19:55:35 Andreas Oberritter wrote: > > /* show speed every SPEED_PKTS_INTERVAL packets */ > > if (!(demux->speed_pkts_cnt % SPEED_PKTS_INTERVAL)) { > > - cur_time = current_kernel_time(); > > + cur_time = ktime_get(); > > > > - if (demux->speed_last_time.tv_sec != 0 && > > - demux->speed_last_time.tv_nsec != 0) { > > - delta_time = timespec_sub(cur_time, > > - demux->speed_last_time); > > + if (ktime_to_ns(demux->speed_last_time) == 0) { > > if ktime_to_ns does what I think it does, then you should invert the logic. Thanks for taking a critical look here, you are absolutely right, and I've now fixed it. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/media/dvb-core/demux.h b/drivers/media/dvb-core/demux.h index 833191bcd810..d8e2b1213bef 100644 --- a/drivers/media/dvb-core/demux.h +++ b/drivers/media/dvb-core/demux.h @@ -92,7 +92,7 @@ struct dmx_ts_feed { int type, enum dmx_ts_pes pes_type, size_t circular_buffer_size, - struct timespec timeout); + ktime_t timeout); int (*start_filtering) (struct dmx_ts_feed* feed); int (*stop_filtering) (struct dmx_ts_feed* feed); }; diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c index d0e3f9d85f34..0d20b379eeec 100644 --- a/drivers/media/dvb-core/dmxdev.c +++ b/drivers/media/dvb-core/dmxdev.c @@ -558,7 +558,7 @@ static int dvb_dmxdev_start_feed(struct dmxdev *dmxdev, struct dmxdev_filter *filter, struct dmxdev_feed *feed) { - struct timespec timeout = { 0 }; + ktime_t timeout = ktime_set(0, 0); struct dmx_pes_filter_params *para = &filter->params.pes; dmx_output_t otype; int ret; diff --git a/drivers/media/dvb-core/dvb_demux.c b/drivers/media/dvb-core/dvb_demux.c index 6c7ff0cdcd32..d83dd0eb5757 100644 --- a/drivers/media/dvb-core/dvb_demux.c +++ b/drivers/media/dvb-core/dvb_demux.c @@ -399,28 +399,23 @@ static void dvb_dmx_swfilter_packet(struct dvb_demux *demux, const u8 *buf) int dvr_done = 0; if (dvb_demux_speedcheck) { - struct timespec cur_time, delta_time; + ktime_t cur_time; u64 speed_bytes, speed_timedelta; demux->speed_pkts_cnt++; /* show speed every SPEED_PKTS_INTERVAL packets */ if (!(demux->speed_pkts_cnt % SPEED_PKTS_INTERVAL)) { - cur_time = current_kernel_time(); + cur_time = ktime_get(); - if (demux->speed_last_time.tv_sec != 0 && - demux->speed_last_time.tv_nsec != 0) { - delta_time = timespec_sub(cur_time, - demux->speed_last_time); + if (ktime_to_ns(demux->speed_last_time) == 0) { speed_bytes = (u64)demux->speed_pkts_cnt * 188 * 8; /* convert to 1024 basis */ speed_bytes = 1000 * div64_u64(speed_bytes, 1024); - speed_timedelta = - (u64)timespec_to_ns(&delta_time); - speed_timedelta = div64_u64(speed_timedelta, - 1000000); /* nsec -> usec */ + speed_timedelta = ktime_ms_delta(cur_time, + demux->speed_last_time); printk(KERN_INFO "TS speed %llu Kbits/sec \n", div64_u64(speed_bytes, speed_timedelta)); @@ -667,7 +662,7 @@ out: static int dmx_ts_feed_set(struct dmx_ts_feed *ts_feed, u16 pid, int ts_type, enum dmx_ts_pes pes_type, - size_t circular_buffer_size, struct timespec timeout) + size_t circular_buffer_size, ktime_t timeout) { struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed; struct dvb_demux *demux = feed->demux; diff --git a/drivers/media/dvb-core/dvb_demux.h b/drivers/media/dvb-core/dvb_demux.h index ae7fc33c3231..5ed3cab4ad28 100644 --- a/drivers/media/dvb-core/dvb_demux.h +++ b/drivers/media/dvb-core/dvb_demux.h @@ -83,7 +83,7 @@ struct dvb_demux_feed { u8 *buffer; int buffer_size; - struct timespec timeout; + ktime_t timeout; struct dvb_demux_filter *filter; int ts_type; @@ -134,7 +134,7 @@ struct dvb_demux { uint8_t *cnt_storage; /* for TS continuity check */ - struct timespec speed_last_time; /* for TS speed check */ + ktime_t speed_last_time; /* for TS speed check */ uint32_t speed_pkts_cnt; /* for TS speed check */ }; diff --git a/drivers/media/dvb-core/dvb_net.c b/drivers/media/dvb-core/dvb_net.c index b81e026edab3..df3ba15c007e 100644 --- a/drivers/media/dvb-core/dvb_net.c +++ b/drivers/media/dvb-core/dvb_net.c @@ -998,7 +998,7 @@ static int dvb_net_feed_start(struct net_device *dev) netdev_dbg(dev, "start filtering\n"); priv->secfeed->start_filtering(priv->secfeed); } else if (priv->feedtype == DVB_NET_FEEDTYPE_ULE) { - struct timespec timeout = { 0, 10000000 }; // 10 msec + ktime_t timeout = ns_to_ktime(10 * NSEC_PER_MSEC); /* we have payloads encapsulated in TS */ netdev_dbg(dev, "alloc tsfeed\n");
The dvb demuxer code uses a 'struct timespec' to pass a timeout as absolute time. This will cause problems on 32-bit architectures in 2038 when time_t overflows, and it is racy with a concurrent settimeofday() call. This patch changes the code to use ktime_get() instead, using the monotonic time base to avoid both the race and the overflow. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/media/dvb-core/demux.h | 2 +- drivers/media/dvb-core/dmxdev.c | 2 +- drivers/media/dvb-core/dvb_demux.c | 17 ++++++----------- drivers/media/dvb-core/dvb_demux.h | 4 ++-- drivers/media/dvb-core/dvb_net.c | 2 +- 5 files changed, 11 insertions(+), 16 deletions(-)