From aa2bf9bc6414b6972b9e51903c1ce7b1f057aee2 Mon Sep 17 00:00:00 2001 From: Sasikantha babu Date: Wed, 21 Mar 2012 20:10:54 +0530 Subject: itimer: Schedule silent NULL pointer fixup in setitimer() for removal setitimer() should return -EFAULT if called with an invalid pointer for value. The current code excludes a NULL pointer from this rule and silently uses it to stop the timer. This violates the spec. Warn about user space apps which rely on that feature and schedule it for removal. [ tglx: Massaged changelog, warn message and Doc entry ] Signed-off-by: Sasikantha babu Link: http://lkml.kernel.org/r/1332340854-26053-1-git-send-email-sasikanth.v19@gmail.com Signed-off-by: Thomas Gleixner --- kernel/itimer.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/itimer.c b/kernel/itimer.c index 22000c3db0dd..c70369a74b5a 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -284,8 +284,11 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, if (value) { if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) return -EFAULT; - } else + } else { memset((char *) &set_buffer, 0, sizeof(set_buffer)); + WARN_ONCE(1, "setitimer: new_value pointer is NULL." + " Misfeature support will be removed\n"); + } error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); if (error || !ovalue) -- cgit v1.2.1 From 3872c48b14259d8c0a00c9fff06a4a4123f7f4eb Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 31 Mar 2012 12:45:43 +0200 Subject: tick: Document TICK_ONESHOT config option This option has been selected from arch code as it was assumed that it's necessary to support oneshot mode clockevent devices. But it's just a core internal helper to compile tick-oneshot.c if NOHZ or HIG_RES_TIMERS are selected. Reported-by: Russell King Signed-off-by: Thomas Gleixner --- kernel/time/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 2cf9cc7aa103..a20dc8a3c949 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -1,6 +1,10 @@ # # Timer subsystem related configuration options # + +# Core internal switch. Selected by NO_HZ / HIGH_RES_TIMERS. This is +# only related to the tick functionality. Oneshot clockevent devices +# are supported independ of this. config TICK_ONESHOT bool -- cgit v1.2.1 From 6f103929f8979d2638e58d7f7fda0beefcb8ee7e Mon Sep 17 00:00:00 2001 From: Neal Cardwell Date: Tue, 27 Mar 2012 15:09:37 -0400 Subject: nohz: Fix stale jiffies update in tick_nohz_restart() Fix tick_nohz_restart() to not use a stale ktime_t "now" value when calling tick_do_update_jiffies64(now). If we reach this point in the loop it means that we crossed a tick boundary since we grabbed the "now" timestamp, so at this point "now" refers to a time in the old jiffy, so using the old value for "now" is incorrect, and is likely to give us a stale jiffies value. In particular, the first time through the loop the tick_do_update_jiffies64(now) call is always a no-op, since the caller, tick_nohz_restart_sched_tick(), will have already called tick_do_update_jiffies64(now) with that "now" value. Note that tick_nohz_stop_sched_tick() already uses the correct approach: when we notice we cross a jiffy boundary, grab a new timestamp with ktime_get(), and *then* update jiffies. Signed-off-by: Neal Cardwell Cc: Ben Segall Cc: Ingo Molnar Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1332875377-23014-1-git-send-email-ncardwell@google.com Signed-off-by: Thomas Gleixner --- kernel/time/tick-sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 3526038f2836..6a3a5b9ff561 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -534,9 +534,9 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now) hrtimer_get_expires(&ts->sched_timer), 0)) break; } - /* Update jiffies and reread time */ - tick_do_update_jiffies64(now); + /* Reread time and update jiffies */ now = ktime_get(); + tick_do_update_jiffies64(now); } } -- cgit v1.2.1 From 9886f444129171569461d8c39983e16f4871e3b4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 10 Apr 2012 10:50:55 +0200 Subject: itimer: Use printk_once instead of WARN_ONCE David pointed out, that WARN_ONCE() to report usage of an deprecated misfeature make folks unhappy. Use printk_once() instead. Andrew told me to stop grumbling and to remove the silly typecast while touching the file. Reported-by: David Rientjes Cc: Andrew Morton Signed-off-by: Thomas Gleixner --- kernel/itimer.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/itimer.c b/kernel/itimer.c index c70369a74b5a..8d262b467573 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -285,9 +285,10 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) return -EFAULT; } else { - memset((char *) &set_buffer, 0, sizeof(set_buffer)); - WARN_ONCE(1, "setitimer: new_value pointer is NULL." - " Misfeature support will be removed\n"); + memset(&set_buffer, 0, sizeof(set_buffer)); + printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer." + " Misfeature support will be removed\n", + current->comm); } error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); -- cgit v1.2.1 From fa4da365bc7772c2cd6d5405bdf151612455f957 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 9 Apr 2012 15:41:44 -0700 Subject: clockevents: tTack broadcast device mode change in tick_broadcast_switch_to_oneshot() In the commit 77b0d60c5adf39c74039e2142a1d3cd1e4d53799, "clockevents: Leave the broadcast device in shutdown mode when not needed", we were bailing out too quickly in tick_broadcast_switch_to_oneshot(), with out tracking the broadcast device mode change to 'TICKDEV_MODE_ONESHOT'. This breaks the platforms which need broadcast device oneshot services during deep idle states. tick_broadcast_oneshot_control() thinks that it is in periodic mode and fails to take proper decisions based on the CLOCK_EVT_NOTIFY_BROADCAST_[ENTER, EXIT] notifications during deep idle entry/exit. Fix this by tracking the broadcast device mode as 'TICKDEV_MODE_ONESHOT', before leaving the broadcast HW device in shutdown mode if there are no active requests for the moment. Reported-and-tested-by: Santosh Shilimkar Signed-off-by: Suresh Siddha Cc: johnstul@us.ibm.com Link: http://lkml.kernel.org/r/1334011304.12400.81.camel@sbsiddha-desk.sc.intel.com Signed-off-by: Thomas Gleixner --- kernel/time/tick-broadcast.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index e883f57a3cd3..bf57abdc7bd0 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -575,10 +575,12 @@ void tick_broadcast_switch_to_oneshot(void) unsigned long flags; raw_spin_lock_irqsave(&tick_broadcast_lock, flags); + + tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT; + if (cpumask_empty(tick_get_broadcast_mask())) goto end; - tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT; bc = tick_broadcast_device.evtdev; if (bc) tick_broadcast_setup_oneshot(bc); -- cgit v1.2.1