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2008-02-03Remove one useless extern declarationPierre Peiffer
The file exit.c contains one useless extern declaration of sem_exit(). Moreover, it refers to nothing. This trivial patch removes it. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Signed-off-by: Adrian Bunk <bunk@kernel.org>
2008-02-02Merge branch 'suspend' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 * 'suspend' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (38 commits) suspend: cleanup reference to swsusp_pg_dir[] PM: Remove obsolete /sys/devices/.../power/state docs Hibernation: Invoke suspend notifications after console switch Suspend: Invoke suspend notifications after console switch Suspend: Clean up suspend_64.c Suspend: Add config option to disable the freezer if architecture wants that ACPI: Print message before calling _PTS ACPI hibernation: Call _PTS before suspending devices Hibernation: Introduce begin() and end() callbacks ACPI suspend: Call _PTS before suspending devices ACPI: Separate disabling of GPEs from _PTS ACPI: Separate invocations of _GTS and _BFS from _PTS and _WAK Suspend: Introduce begin() and end() callbacks suspend: fix ia64 allmodconfig build ACPI: clear GPE earily in resume to avoid warning Suspend: Clean up Kconfig (V2) Hibernation: Clean up Kconfig (V2) Hibernation: Update messages Suspend: Use common prefix in messages Hibernation: Remove unnecessary variable declaration ...
2008-02-02debug: softlockup looping fixPeter Zijlstra
Rafael J. Wysocki reported weird, multi-seconds delays during suspend/resume and bisected it back to: commit 82a1fcb90287052aabfa235e7ffc693ea003fe69 Author: Ingo Molnar <mingo@elte.hu> Date: Fri Jan 25 21:08:02 2008 +0100 softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks fix it: - restore the old wakeup mechanism - fix break usage in do_each_thread() { } while_each_thread(). - fix the hotplug switch stmt, a fall-through case was broken. Bisected-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01Hibernation: Invoke suspend notifications after console switchRafael J. Wysocki
Following the recent change in the suspend code path, switch consoles before calling PM notifiers during hibernation. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Invoke suspend notifications after console switchJohannes Berg
In order to fix APM emulation it is necessary to enable apm-emulation notifications for suspends triggered in various ways via the suspend notifiers. However, this will cause the systems using APM emulation to lock up between X being needed to switch away from the VT and X already waiting for resume in the APM ioctl. This patch moves the console switch (if enabled) before the suspend notification (and after the resume notification) to avoid this issue. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Add config option to disable the freezer if architecture wants thatJohannes Berg
This patch makes the freezer optional for suspend to allow the system to work (or not work) like the original PMU suspend. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Introduce begin() and end() callbacksRafael J. Wysocki
Introduce global hibernation callback .end() and rename global hibernation callback .start() to .begin(), in analogy with the recent modifications of the global suspend callbacks. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Introduce begin() and end() callbacksRafael J. Wysocki
On ACPI systems the target state set by acpi_pm_set_target() is reset by acpi_pm_finish(), but that need not be called if the suspend fails.  All platforms that use the .set_target() global suspend callback are affected by analogous issues. For this reason, we need an additional global suspend callback that will reset the target state regardless of whether or not the suspend is successful.  Also, it is reasonable to rename the .set_target() callback, since it will be used for a different purpose on ACPI systems (due to ACPI 1.0x code ordering requirements). Introduce the global suspend callback .end() to be executed at the end of the suspend sequence and rename the .set_target() global suspend callback to .begin(). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01suspend: fix ia64 allmodconfig buildRafael J. Wysocki
kernel/power/main.c:488: error: ‘pm_test_attr’ undeclared here (not in a function) Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Clean up Kconfig (V2)Johannes Berg
This cleans up the suspend Kconfig and removes the need to declare centrally which architectures support suspend. All architectures that currently support suspend are modified accordingly. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Russell King <rmk@arm.linux.org.uk> Acked-by: Paul Mackerras <paulus@samba.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Pavel Machek <pavel@suse.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Clean up Kconfig (V2)Johannes Berg
This cleans up the hibernation Kconfig and removes the need to declare centrally which architectures support hibernation. All architectures that currently support hibernation are modified accordingly. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Paul Mackerras <paulus@samba.org> Cc: Pavel Machek <pavel@suse.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Update messagesRafael J. Wysocki
Make hibernation messages start with one common prefix "PM: " and use the word "hibernation" in the messages as a synonym of "suspend to disk". Turn some KERN_INFO messages into debug ones. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Use common prefix in messagesRafael J. Wysocki
Make suspend messages start with one common prefix "PM: ". Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Remove unnecessary variable declarationRafael J. Wysocki
Remove the unnecessary extern declaration of resume_file[] from kernel/power/swap.c . Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Fix comment in disk.cRafael J. Wysocki
Fix a comment in kernel/power/disk.c so that it doesn't contain lines longer that 80 characters. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Fix comment in main.cRafael J. Wysocki
Fix a comment in kernel/power/main.c so that it doesn't contain lines longer that 80 characters. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Move low level resume to disk.cRafael J. Wysocki
Move the low level restore code to kernel/power/disk.c , since the corresponding low level hibernation code is already there. Make restore fail if device_power_down(PMSG_PRETHAW) returns an error. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Fix compilation warning for CONFIG_SUSPEND unsetRafael J. Wysocki
Suspend: Make debug facility depend on CONFIG_SUSPEND Make the new suspend debug facility code depend on CONFIG_SUSPEND, as appropriate, to remove the compiler warning printed when CONFIG_PM is set and CONFIG_SUSPEND is not set. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01PM: Convert PM notifiers to out-of-line codeAlan Stern
This patch (as1008b) converts the PM notifier routines from inline calls to out-of-line code. It also prevents pm_chain_head from being created when CONFIG_PM_SLEEP isn't enabled, and EXPORTs the notifier registration and unregistration routines. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01PM: Make PM_TRACE more architecture independentJohannes Berg
When trying to debug a suspend failure I started implementing PM_TRACE for powerpc. I then noticed that I'm debugging a suspend failure and so PM_TRACE isn't useful at all, but thought that nonetheless this could be useful in the future. Basically, to support PM_TRACE, you add a Kconfig option that selects PM_TRACE and provides the infrastructure as per the help text of PM_TRACE. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: New testing facility (rev. 2)Rafael J. Wysocki
Make it possible to test the hibernation core code with the help of the /sys/power/pm_test attribute introduced for suspend testing in the previous patch. Writing an appropriate string to this file causes the hibernation code to work in one of the test modes defined as follows: freezer - test the freezing of processes devices - test the freezing of processes and suspending of devices platform - test the freezing of processes, suspending of devices and platform global   control methods(*) processors - test the freezing of processes, suspending of devices, platform global   control methods(*) and the disabling of nonboot CPUs core - test the freezing of processes, suspending of devices, platform global   control methods(*), the disabling of nonboot CPUs and suspending of   platform/system devices (*) - the platform global control methods are only available on ACPI systems       and are only tested if the hibernation mode is set to "platform" Then, if a hibernation is started by normal means, the hibernation core will perform its normal operations up to the point indicated by given test level. Next, it will wait for 5 seconds and carry out the resume operations needed to transition the system back to the fully functional state. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01suspend: build fix responding to 2.6.25 kset changeRafael J. Wysocki
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Suspend: Testing facility (rev. 2)Rafael J. Wysocki
Introduce sysfs attribute /sys/power/pm_test allowing one to test the suspend core code.  Namely, writing one of the strings: freezer devices platform processors core to this file causes the suspend code to work in one of the test modes defined as follows: freezer - test the freezing of processes devices - test the freezing of processes and suspending of devices platform - test the freezing of processes, suspending of devices and platform global   control methods(*) processors - test the freezing of processes, suspending of devices, platform global   control methods and the disabling of nonboot CPUs core - test the freezing of processes, suspending of devices, platform global   control methods, the disabling of nonboot CPUs and suspending of   platform/system devices (*) These are ACPI global control methods on ACPI systems Then, if a suspend is started by normal means, the suspend core will perform its normal operations up to the point indicated by given test level.  Next, it will wait for 5 seconds and carry out the resume operations needed to transition the system back to the fully functional state. Writing "none" to /sys/power/pm_test turns the testing off. When open for reading, /sys/power/pm_test contains a space-separated list of all available tests (including "none" that represents the normal functionality) in which the current test level is indicated by square brackets. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Add PM_RESTORE_PREPARE and PM_POST_RESTORE notifiers (rev. 2)Alan Stern
Add PM_RESTORE_PREPARE and PM_POST_RESTORE notifiers to the PM core, to be used in analogy with the existing PM_HIBERNATION_PREPARE and PM_POST_HIBERNATION notifiers. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Move function prototypes to headerAdrian Bunk
This patch moves the prototypes of count_highmem_pages() and restore_highmem() to kernel/power/power.h Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Introduce exportable suspend ioctls header (rev. 2)Rafael J. Wysocki
Move the definitions of hibernation ioctls to a separate header file in include/linux, which can be exported to the user space. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Correct definitions of some ioctls (rev. 2)Rafael J. Wysocki
Three ioctl numbers belonging to the hibernation userland interface, SNAPSHOT_ATOMIC_SNAPSHOT, SNAPSHOT_AVAIL_SWAP, SNAPSHOT_GET_SWAP_PAGE, are defined in a wrong way (eg. not portable). Provide new ioctl numbers for these ioctls and mark the existing ones as deprecated. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Mark SNAPSHOT_SET_SWAP_FILE ioctl as deprecated (rev. 2)Rafael J. Wysocki
Mark the SNAPSHOT_SET_SWAP_FILE ioctl belonging to the hibernation userland interface as deprecated. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Rework platform support ioctls (rev. 2)Rafael J. Wysocki
Modify the hibernation userland interface by adding two new ioctls to it, SNAPSHOT_PLATFORM_SUPPORT and SNAPSHOT_POWER_OFF, that can be used, respectively, to switch the hibernation platform support on/off and to make the kernel transition the system to the hibernation state (eg. ACPI S4) using the platform (eg. ACPI) driver. These ioctls are intended to replace the misdesigned SNAPSHOT_PMOPS ioctl, which from now is regarded as obsolete and will be removed in the future. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01Hibernation: Introduce SNAPSHOT_GET_IMAGE_SIZE ioctlRafael J. Wysocki
Add a new ioctl, SNAPSHOT_GET_IMAGE_SIZE, returning the size of the (just created) hibernation image, to the hibernation userland interface. This ioctl is necessary so that the userland utilities using the interface need not access the hibernation image header, owned by the kernel, in order to obtain the size of the image. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-02Merge branch 'audit.b46' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current * 'audit.b46' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: [AUDIT] Add uid, gid fields to ANOM_PROMISCUOUS message [AUDIT] ratelimit printk messages audit [patch 2/2] audit: complement va_copy with va_end() [patch 1/2] kernel/audit.c: warning fix [AUDIT] create context if auditing was ever enabled [AUDIT] clean up audit_receive_msg() [AUDIT] make audit=0 really stop audit messages [AUDIT] break large execve argument logging into smaller messages [AUDIT] include audit type in audit message when using printk [AUDIT] do not panic on exclude messages in audit_log_pid_context() [AUDIT] Add End of Event record [AUDIT] add session id to audit messages [AUDIT] collect uid, loginuid, and comm in OBJ_PID records [AUDIT] return EINTR not ERESTART* [PATCH] get rid of loginuid races [PATCH] switch audit_get_loginuid() to task_struct *
2008-02-01[AUDIT] ratelimit printk messages auditEric Paris
some printk messages from the audit system can become excessive. This patch ratelimits those messages. It was found that messages, such as the audit backlog lost printk message could flood the logs to the point that a machine could take an nmi watchdog hit or otherwise become unresponsive. Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[patch 2/2] audit: complement va_copy with va_end()Richard Knutsson
Complement va_copy() with va_end(). Signed-off-by: Richard Knutsson <ricknu-0@student.ltu.se> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2008-02-01[patch 1/2] kernel/audit.c: warning fixAndrew Morton
kernel/audit.c: In function 'audit_log_start': kernel/audit.c:1133: warning: 'serial' may be used uninitialized in this function Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2008-02-01[AUDIT] create context if auditing was ever enabledEric Paris
Disabling audit at runtime by auditctl doesn't mean that we can stop allocating contexts for new processes; we don't want to miss them when that sucker is reenabled. (based on work from Al Viro in the RHEL kernel series) Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] clean up audit_receive_msg()Eric Paris
generally clean up audit_receive_msg() don't free random memory if selinux_sid_to_string fails for some reason. Move generic auditing to a helper function Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] make audit=0 really stop audit messagesEric Paris
Some audit messages (namely configuration changes) are still emitted even if the audit subsystem has been explicitly disabled. This patch turns those messages off as well. Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] break large execve argument logging into smaller messagesEric Paris
execve arguments can be quite large. There is no limit on the number of arguments and a 4G limit on the size of an argument. this patch prints those aruguments in bite sized pieces. a userspace size limitation of 8k was discovered so this keeps messages around 7.5k single arguments larger than 7.5k in length are split into multiple records and can be identified as aX[Y]= Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] include audit type in audit message when using printkEric Paris
Currently audit drops the audit type when an audit message goes through printk instead of the audit deamon. This is a minor annoyance in that the audit type is no longer part of the message and the information the audit type conveys needs to be carried in, or derived from the message data. The attached patch includes the type number as part of the printk. Admittedly it isn't the type name that the audit deamon provides but I think this is better than dropping the type completely. Signed-pff-by: John Johansen <jjohansen@suse.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] do not panic on exclude messages in audit_log_pid_context()Eric Paris
If we fail to get an ab in audit_log_pid_context this may be due to an exclude rule rather than a memory allocation failure. If it was due to a memory allocation failue we would have already paniced and no need to do it again. Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] Add End of Event recordEric Paris
This patch adds an end of event record type. It will be sent by the kernel as the last record when a multi-record event is triggered. This will aid realtime analysis programs since they will now reliably know they have the last record to complete an event. The audit daemon filters this and will not write it to disk. Signed-off-by: Steve Grubb <sgrubb redhat com> Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] add session id to audit messagesEric Paris
In order to correlate audit records to an individual login add a session id. This is incremented every time a user logs in and is included in almost all messages which currently output the auid. The field is labeled ses= or oses= Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] collect uid, loginuid, and comm in OBJ_PID recordsEric Paris
Add uid, loginuid, and comm collection to OBJ_PID records. This just gives users a little more information about the task that received a signal. pid is rather meaningless after the fact, and even though comm isn't great we can't collect exe reasonably on this code path for performance reasons. Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[AUDIT] return EINTR not ERESTART*Eric Paris
The syscall exit code will change ERESTART* kernel internal return codes to EINTR if it does not restart the syscall. Since we collect the audit info before that point we should fix those in the audit log as well. Signed-off-by: Eric Paris <eparis@redhat.com>
2008-02-01[PATCH] get rid of loginuid racesAl Viro
Keeping loginuid in audit_context is racy and results in messier code. Taken to task_struct, out of the way of ->audit_context changes. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-02-01[PATCH] switch audit_get_loginuid() to task_struct *Al Viro
all callers pass something->audit_context Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-02-01futex: Add bitset conditional wait/wakeup functionalityThomas Gleixner
To allow the implementation of optimized rw-locks in user space, glibc needs a possibility to select waiters for wakeup depending on a bitset mask. This requires two new futex OPs: FUTEX_WAIT_BITS and FUTEX_WAKE_BITS These OPs are basically the same as FUTEX_WAIT and FUTEX_WAKE plus an additional argument - a bitset. Further the FUTEX_WAIT_BITS OP is expecting an absolute timeout value instead of the relative one, which is used for the FUTEX_WAIT OP. FUTEX_WAIT_BITS calls into the kernel with a bitset. The bitset is stored in the futex_q structure, which is used to enqueue the waiter into the hashed futex waitqueue. FUTEX_WAKE_BITS also calls into the kernel with a bitset. The wakeup function logically ANDs the bitset with the bitset stored in each waiters futex_q structure. If the result is zero (i.e. none of the set bits in the bitsets is matching), then the waiter is not woken up. If the result is not zero (i.e. one of the set bits in the bitsets is matching), then the waiter is woken. The bitset provided by the caller must be non zero. In case the provided bitset is zero the kernel returns EINVAL. Internaly the new OPs are only extensions to the existing FUTEX_WAIT and FUTEX_WAKE functions. The existing OPs hand a bitset with all bits set into the futex_wait() and futex_wake() functions. Signed-off-by: Thomas Gleixner <tgxl@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-01futex: Remove warn on in return fixup pathThomas Gleixner
The WARN_ON() in the fixup return path of futex_lock_pi() can trigger with false positives. The following scenario happens: t1 holds the futex and t2 and t3 are blocked on the kernel side rt_mutex. t1 releases the futex (and the rt_mutex) and assigned t2 to be the next owner of the futex. t2 is interrupted and returns w/o acquiring the rt_mutex, before t1 can release the rtmutex. t1 releases the rtmutex and t3 becomes the pending owner of the rtmutex. t2 notices that it is the designated owner (user space variable) and fails to acquire the rt_mutex via trylock, because it is not allowed to steal the rt_mutex from t3. Now it looks at the rt_mutex pending owner (t3) and assigns the futex and the pi_state to it. During the fixup t4 steals the rtmutex from t3. t2 returns from the fixup and the owner of the rt_mutex has changed from t3 to t4. There is no need to do another round of fixups from t2. The important part (t2 is not returning as the user space visible owner) is done. The further fixups are done, before either t3 or t4 return to user space. For the user space it is not relevant which task (t3 or t4) is the real owner, as long as those are both in the kernel, which is guaranteed by the serialization of the hash bucket lock. Both tasks (which ever returns first to userspace - t4 because it locked the rt_mutex or t3 due to a signal) are going through the lock_futex_pi() return path where the ownership is fixed before the return to user space. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-01tick-sched: add more debug informationThomas Gleixner
To allow better diagnosis of tick-sched related, especially NOHZ related problems, we need to know when the last wakeup via an irq happened and when the CPU left the idle state. Add two fields (idle_waketime, idle_exittime) to the tick_sched structure and add them to the timer_list output. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-01timekeeping: update xtime_cache when time(zone) changesThomas Gleixner
xtime_cache needs to be updated whenever xtime and or wall_to_monotic are changed. Otherwise users of xtime_cache might see a stale (and in the case of timezone changes utterly wrong) value until the next update happens. Fixup the obvious places, which miss this update. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <johnstul@us.ibm.com> Tested-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>