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  1. 16 May, 2011 1 commit
    • Thomas Gleixner's avatar
      tick: Clear broadcast active bit when switching to oneshot · 07f4beb0
      Thomas Gleixner authored 
      The first cpu which switches from periodic to oneshot mode switches
also the broadcast device into oneshot mode. The broadcast device
serves as a backup for per cpu timers which stop in deeper
C-states. To avoid starvation of the cpus which might be in idle and
depend on broadcast mode it marks the other cpus as broadcast active
and sets the brodcast expiry value of those cpus to the next tick.

The oneshot mode broadcast bit for the other cpus is sticky and gets
only cleared when those cpus exit idle. If a cpu was not idle while
the bit got set in consequence the bit prevents that the broadcast
device is armed on behalf of that cpu when it enters idle for the
first time after it switched to oneshot mode.

In most cases that goes unnoticed as one of the other cpus has usually
a timer pending which keeps the broadcast device armed with a short
timeout. Now if the only cpu which has a short timer active has the
bit set then the broadcast device will not be armed on behalf of that
cpu and will fire way after the expected timer expiry. In the case of
Christians bug report it took ~145 seconds which is about half of the
wrap around time of HPET (the limit for that device) due to the fact
that all other cpus had no timers armed which expired before the 145
seconds timeframe.

The solution is simply to clear the broadcast active bit
unconditionally when a cpu switches to oneshot mode after the first
cpu switched the broadcast device over. It's not idle at that point
otherwise it would not be executing that code.

[ I fundamentally hate that broadcast crap. Why the heck thought some
  folks that when going into deep idle it's a brilliant concept to
  switch off the last device which brings the cpu back from that
  state? ]

Thanks to Christian for providing all the valuable debug information!
Reported-and-tested-by: default avatarChristian Hoffmann <email@christianhoffmann.info>
Cc: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1105161105170.3078%40ionos%3E
Cc: stable@kernel.org
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      07f4beb0
  3. 12 May, 2011 1 commit
  5. 07 May, 2011 11 commits
    • Uwe Kleine-König's avatar
      rtc: mc13xxx: Don't call rtc_device_register while holding lock · 156229b3
      Uwe Kleine-König authored 
      Since commit f44f7f96 (RTC: Initialize kernel state from RTC)
rtc_device_register reads the programmed alarm. As reading the alarm
needs to take the mc13xxx lock, release it before calling
rtc_device_register.

This fixes a deadlock during boot:

	INFO: task swapper:1 blocked for more than 120 seconds.
	"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
	swapper         D c02b175c     0     1      0 0x00000000
	[<c02b175c>] (schedule+0x304/0x4f4) from [<c02b25a8>] (__mutex_lock_slowpath+0x7c/0x110)
	[<c02b25a8>] (__mutex_lock_slowpath+0x7c/0x110) from [<c020b4cc>] (mc13xxx_rtc_read_time+0x1c/0x118)
	[<c020b4cc>] (mc13xxx_rtc_read_time+0x1c/0x118) from [<c0208f04>] (__rtc_read_time+0x58/0x5c)
	[<c0208f04>] (__rtc_read_time+0x58/0x5c) from [<c0209508>] (rtc_read_time+0x30/0x48)
	[<c0209508>] (rtc_read_time+0x30/0x48) from [<c0209dd4>] (__rtc_read_alarm+0x1c/0x290)
	[<c0209dd4>] (__rtc_read_alarm+0x1c/0x290) from [<c0208d58>] (rtc_device_register+0x150/0x27c)
	[<c0208d58>] (rtc_device_register+0x150/0x27c) from [<c02b0b74>] (mc13xxx_rtc_probe+0x128/0x17c)
	[<c02b0b74>] (mc13xxx_rtc_probe+0x128/0x17c) from [<c01d5280>] (platform_drv_probe+0x1c/0x24)
	[<c01d5280>] (platform_drv_probe+0x1c/0x24) from [<c01d3e58>] (driver_probe_device+0x80/0x1a8)
	[<c01d3e58>] (driver_probe_device+0x80/0x1a8) from [<c01d400c>] (__driver_attach+0x8c/0x90)
	[<c01d400c>] (__driver_attach+0x8c/0x90) from [<c01d3654>] (bus_for_each_dev+0x60/0x8c)
	[<c01d3654>] (bus_for_each_dev+0x60/0x8c) from [<c01d2f6c>] (bus_add_driver+0x180/0x248)
	[<c01d2f6c>] (bus_add_driver+0x180/0x248) from [<c01d4664>] (driver_register+0x70/0x15c)
	[<c01d4664>] (driver_register+0x70/0x15c) from [<c01d5700>] (platform_driver_probe+0x18/0x98)
	[<c01d5700>] (platform_driver_probe+0x18/0x98) from [<c00273a8>] (do_one_initcall+0x2c/0x168)
	[<c00273a8>] (do_one_initcall+0x2c/0x168) from [<c00083ac>] (kernel_init+0xa0/0x150)
	[<c00083ac>] (kernel_init+0xa0/0x150) from [<c0033ff8>] (kernel_thread_exit+0x0/0x8)
Reported-by: default avatarVagrant Cascadian <vagrant@debian.org>
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Closes: http://bugs.debian.org/625804
[Tweaked commit log -jstultz]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      156229b3
    • John Stultz's avatar
      rtc: rp5c01: Initialize drvdata before registering device · 130107b2
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      130107b2
    • John Stultz's avatar
      rtc: pcap: Initialize drvdata before registering device · 4b3687f9
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      4b3687f9
    • John Stultz's avatar
      rtc: msm6242: Initialize drvdata before registering device · 93015236
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      93015236
    • John Stultz's avatar
      rtc: max8998: Initialize drvdata before registering device · 03cf7c47
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      03cf7c47
    • John Stultz's avatar
      rtc: max8925: Initialize drvdata before registering device · 2f5c4fe8
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      2f5c4fe8
    • John Stultz's avatar
      rtc: m41t80: Initialize clientdata before registering device · a015dbc1
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the clientdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the clientdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      a015dbc1
    • John Stultz's avatar
      rtc: ds1286: Initialize drvdata before registering device · 9a281a67
      John Stultz authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      9a281a67
    • Wolfram Sang's avatar
      rtc: ep93xx: Initialize drvdata before registering device · 92d921c5
      Wolfram Sang authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
[Fixed up commit log -jstultz]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      92d921c5
    • Wolfram Sang's avatar
      rtc: davinci: Initialize drvdata before registering device · f4e708ae
      Wolfram Sang authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
[fixed up commit log -jstultz]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      f4e708ae
    • Wolfram Sang's avatar
      rtc: mxc: Initialize drvdata before registering device · 5f54c8a0
      Wolfram Sang authored 
      Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
[fixed up commit log -jstultz]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      5f54c8a0
  7. 05 May, 2011 1 commit
  9. 04 May, 2011 13 commits
  11. 03 May, 2011 13 commits
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