user/sven/linux.git/include/linux/nmi.h, branch v4.4.2

kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup

2015-11-06T03:34:48Z

In many cases of hardlockup reports, it's actually not possible to know why it triggered, because the CPU that got stuck is usually waiting on a resource (with IRQs disabled) in posession of some other CPU is holding. IOW, we are often looking at the stacktrace of the victim and not the actual offender. Introduce sysctl / cmdline parameter that makes it possible to have hardlockup detector perform all-CPU backtrace. Signed-off-by: Jiri Kosina Reviewed-by: Aaron Tomlin Cc: Ulrich Obergfell Acked-by: Don Zickus Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'nmi' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

2015-09-08T19:28:10Z

Pull NMI backtrace update from Russell King: "These changes convert the x86 NMI handling to be a library implementation which other architectures can make use of. Thomas Gleixner has reviewed and tested these changes, and wishes me to send these rather than taking them through the tip tree. The final patch in the set adds an initial implementation using this infrastructure to ARM, even though it doesn't send the IPI at "NMI" level. Patches are in progress to add the ARM equivalent of NMI, but we still need the IRQ-level fallback for systems where the "NMI" isn't available due to secure firmware denying access to it" * 'nmi' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: ARM: add basic support for on-demand backtrace of other CPUs nmi: x86: convert to generic nmi handler nmi: create generic NMI backtrace implementation

watchdog: rename watchdog_suspend() and watchdog_resume()

2015-09-04T23:54:41Z

Rename watchdog_suspend() to lockup_detector_suspend() and watchdog_resume() to lockup_detector_resume() to avoid confusion with the watchdog subsystem and to be consistent with the existing name lockup_detector_init(). Also provide comment blocks to explain the watchdog_running and watchdog_suspended variables and their relationship. Signed-off-by: Ulrich Obergfell Reviewed-by: Aaron Tomlin Cc: Guenter Roeck Cc: Don Zickus Cc: Ulrich Obergfell Cc: Jiri Olsa Cc: Michal Hocko Cc: Stephane Eranian Cc: Chris Metcalf Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

watchdog: use suspend/resume interface in fixup_ht_bug()

2015-09-04T23:54:41Z

Remove watchdog_nmi_disable_all() and watchdog_nmi_enable_all() since these functions are no longer needed. If a subsystem has a need to deactivate the watchdog temporarily, it should utilize the watchdog_suspend() and watchdog_resume() functions. [akpm@linux-foundation.org: fix build with CONFIG_LOCKUP_DETECTOR=m] Signed-off-by: Ulrich Obergfell Reviewed-by: Aaron Tomlin Cc: Guenter Roeck Cc: Don Zickus Cc: Ulrich Obergfell Cc: Jiri Olsa Cc: Michal Hocko Cc: Stephane Eranian Cc: Chris Metcalf Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

watchdog: introduce watchdog_suspend() and watchdog_resume()

2015-09-04T23:54:41Z

This interface can be utilized to deactivate the hard and soft lockup detector temporarily. Callers are expected to minimize the duration of deactivation. Multiple deactivations are allowed to occur in parallel but should be rare in practice. [akpm@linux-foundation.org: remove unneeded static initialization] Signed-off-by: Ulrich Obergfell Reviewed-by: Aaron Tomlin Cc: Guenter Roeck Cc: Don Zickus Cc: Ulrich Obergfell Cc: Jiri Olsa Cc: Michal Hocko Cc: Stephane Eranian Cc: Chris Metcalf Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/watchdog: move NMI function header declarations from watchdog.h to nmi.h

2015-09-04T23:54:41Z

The kernel's NMI watchdog has nothing to do with the watchdog subsystem. Its header declarations should be in linux/nmi.h, not linux/watchdog.h. The code provided two sets of dummy functions if HARDLOCKUP_DETECTOR is not configured, one in the include file and one in kernel/watchdog.c. Remove the dummy functions from kernel/watchdog.c and use those from the include file. Signed-off-by: Guenter Roeck Cc: Stephane Eranian Cc: Peter Zijlstra (Intel) Cc: Ingo Molnar Cc: Don Zickus Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nmi: create generic NMI backtrace implementation

2015-07-17T11:23:17Z

x86s NMI backtrace implementation (for arch_trigger_all_cpu_backtrace()) is fairly generic in nature - the only architecture specific bits are the act of raising the NMI to other CPUs, and reporting the status of the NMI handler. These are fairly simple to factor out, and produce a generic implementation which can be shared between ARM and x86. Reviewed-by: Thomas Gleixner Signed-off-by: Russell King

watchdog: add watchdog_cpumask sysctl to assist nohz

2015-06-25T00:49:40Z

Change the default behavior of watchdog so it only runs on the housekeeping cores when nohz_full is enabled at build and boot time. Allow modifying the set of cores the watchdog is currently running on with a new kernel.watchdog_cpumask sysctl. In the current system, the watchdog subsystem runs a periodic timer that schedules the watchdog kthread to run. However, nohz_full cores are designed to allow userspace application code running on those cores to have 100% access to the CPU. So the watchdog system prevents the nohz_full application code from being able to run the way it wants to, thus the motivation to suppress the watchdog on nohz_full cores, which this patchset provides by default. However, if we disable the watchdog globally, then the housekeeping cores can't benefit from the watchdog functionality. So we allow disabling it only on some cores. See Documentation/lockup-watchdogs.txt for more information. [jhubbard@nvidia.com: fix a watchdog crash in some configurations] Signed-off-by: Chris Metcalf Acked-by: Don Zickus Cc: Ingo Molnar Cc: Ulrich Obergfell Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Frederic Weisbecker Signed-off-by: John Hubbard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

watchdog: introduce the hardlockup_detector_disable() function

2015-04-14T23:48:59Z

Have kvm_guest_init() use hardlockup_detector_disable() instead of watchdog_enable_hardlockup_detector(false). Remove the watchdog_hardlockup_detector_is_enabled() and the watchdog_enable_hardlockup_detector() function which are no longer needed. Signed-off-by: Ulrich Obergfell Signed-off-by: Don Zickus Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

watchdog: enable the new user interface of the watchdog mechanism

2015-04-14T23:48:59Z

With the current user interface of the watchdog mechanism it is only possible to disable or enable both lockup detectors at the same time. This series introduces new kernel parameters and changes the semantics of some existing kernel parameters, so that the hard lockup detector and the soft lockup detector can be disabled or enabled individually. With this series applied, the user interface is as follows. - parameters in /proc/sys/kernel . soft_watchdog This is a new parameter to control and examine the run state of the soft lockup detector. . nmi_watchdog The semantics of this parameter have changed. It can now be used to control and examine the run state of the hard lockup detector. . watchdog This parameter is still available to control the run state of both lockup detectors at the same time. If this parameter is examined, it shows the logical OR of soft_watchdog and nmi_watchdog. . watchdog_thresh The semantics of this parameter are not affected by the patch. - kernel command line parameters . nosoftlockup The semantics of this parameter have changed. It can now be used to disable the soft lockup detector at boot time. . nmi_watchdog=0 or nmi_watchdog=1 Disable or enable the hard lockup detector at boot time. The patch introduces '=1' as a new option. . nowatchdog The semantics of this parameter are not affected by the patch. It is still available to disable both lockup detectors at boot time. Also, remove the proc_dowatchdog() function which is no longer needed. [dzickus@redhat.com: wrote changelog] [dzickus@redhat.com: update documentation for kernel params and sysctl] Signed-off-by: Ulrich Obergfell Signed-off-by: Don Zickus Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds