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2006-11-06[PATCH] sysctl: allow a zero ctl_name in the middle of a sysctl tableEric W. Biederman
Since it is becoming clear that there are just enough users of the binary sysctl interface that completely removing the binary interface from the kernel will not be an option for foreseeable future, we need to find a way to address the sysctl maintenance issues. The basic problem is that sysctl requires one central authority to allocate sysctl numbers, or else conflicts and ABI breakage occur. The proc interface to sysctl does not have that problem, as names are not densely allocated. By not terminating a sysctl table until I have neither a ctl_name nor a procname, it becomes simple to add sysctl entries that don't show up in the binary sysctl interface. Which allows people to avoid allocating a binary sysctl value when not needed. I have audited the kernel code and in my reading I have not found a single sysctl table that wasn't terminated by a completely zero filled entry. So this change in behavior should not affect anything. I think this mechanism eases the pain enough that combined with a little disciple we can solve the reoccurring sysctl ABI breakage. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-06[PATCH] Improve the removed sysctl warningsEric W. Biederman
Don't warn about libpthread's access to kernel.version. When it receives -ENOSYS it will read /proc/sys/kernel/version. If anything else shows up print the sysctl number string. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Cal Peake <cp@absolutedigital.net> Cc: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-06[PATCH] lockdep: fix delayacct locking bugPeter Zijlstra
Make the delayacct lock irqsave; this avoids the possible deadlock where an interrupt is taken while holding the delayacct lock which needs to take the delayacct lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-06[PATCH] Fix the spurious unlock_cpu_hotplug false warningsGautham R Shenoy
Cpu-hotplug locking has a minor race case caused because of setting the variable "recursive" to NULL *after* releasing the cpu_bitmask_lock in the function unlock_cpu_hotplug,instead of doing so before releasing the cpu_bitmask_lock. This was the cause of most of the recent false spurious lock_cpu_unlock warnings. This should fix the problem reported by Martin Lorenz reported in http://lkml.org/lkml/2006/10/29/127. Thanks to Srinivasa DS for pointing it out. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-04Make sure "user->sigpending" count is in syncLinus Torvalds
The previous commit (45c18b0bb579b5c1b89f8c99f1b6ffa4c586ba08, aka "Fix unlikely (but possible) race condition on task->user access") fixed a potential oops due to __sigqueue_alloc() getting its "user" pointer out of sync with switch_user(), and accessing a user pointer that had been de-allocated on another CPU. It still left another (much less serious) problem, where a concurrent __sigqueue_alloc and swich_user could cause sigqueue_alloc to do signal pending reference counting for a _different_ user than the one it then actually ended up using. No oops, but we'd end up with the wrong signal accounting. Another case of Oleg's eagle-eyes picking up the problem. This is trivially fixed by just making sure we load whichever "user" structure we decide to use (it doesn't matter _which_ one we pick, we just need to pick one) just once. Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Andrew Morton <akpm@osdl.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-04Fix unlikely (but possible) race condition on task->user accessLinus Torvalds
There's a possible race condition when doing a "switch_uid()" from one user to another, which could race with another thread doing a signal allocation and looking at the old thread ->user pointer as it is freed. This explains an oops reported by Lukasz Trabinski: http://permalink.gmane.org/gmane.linux.kernel/462241 We fix this by delaying the (reference-counted) freeing of the user structure until the thread signal handler lock has been released, so that we know that the signal allocation has either seen the new value or has properly incremented the reference count of the old one. Race identified by Oleg Nesterov. Cc: Lukasz Trabinski <lukasz@wsisiz.edu.pl> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Andrew Morton <akpm@osdl.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-03[PATCH] Create compat_sys_migrate_pagesStephen Rothwell
This is needed on bigendian 64bit architectures. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-03[PATCH] swsusp: debuggingRafael J. Wysocki
Add a swsusp debugging mode. This does everything that's needed for a suspend except for actually suspending. So we can look in the log messages and work out a) what code is being slow and b) which drivers are misbehaving. (1) # echo testproc > /sys/power/disk # echo disk > /sys/power/state This should turn off the non-boot CPU, freeze all processes, wait for 5 seconds and then thaw the processes and the CPU. (2) # echo test > /sys/power/disk # echo disk > /sys/power/state This should turn off the non-boot CPU, freeze all processes, shrink memory, suspend all devices, wait for 5 seconds, resume the devices etc. Cc: Pavel Machek <pavel@ucw.cz> Cc: Stefan Seyfried <seife@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-03[PATCH] schedule removal of FUTEX_FDAndrew Morton
Apparently FUTEX_FD is unfixably racy and nothing uses it (or if it does, it shouldn't). Add a warning printk, give any remaining users six months to migrate off it. Cc: Ulrich Drepper <drepper@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-03[PATCH] Add printk_timed_ratelimit()Andrew Morton
printk_ratelimit() has global state which makes it not useful for callers which wish to perform ratelimiting at a particular frequency. Add a printk_timed_ratelimit() which utilises caller-provided state storage to permit more flexibility. This function can in fact be used for things other than printk ratelimiting and is perhaps poorly named. Cc: Ulrich Drepper <drepper@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-31[PATCH] taskstats: fix sub-threads accountingOleg Nesterov
If there are no listeners, taskstats_exit_send() just returns because taskstats_exit_alloc() didn't allocate *tidstats. This is wrong, each sub-thread should do fill_tgid_exit() on exit, otherwise its ->delays is not recorded in ->signal->stats and lost. Q: We don't send TASKSTATS_TYPE_AGGR_TGID when single-threaded process exits. Is it good? How can the listener figure out that it was actually a process exit, not sub-thread? Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-30[PATCH] xacct_add_tsk: fix pure theoretical ->mm use-after-freeOleg Nesterov
Paranoid fix. The task can free its ->mm after the 'if (p->mm)' check. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-30[PATCH] ndiswrapper: don't set the module->taints flagsRandy Dunlap
For ndiswrapper, don't set the module->taints flags, just set the kernel global tainted flag. This should allow ndiswrapper to continue to use GPL symbols. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Florin Malita <fmalita@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-29[PATCH] taskstats: fix sk_buff size calculationOleg Nesterov
prepare_reply() adds GENL_HDRLEN to the payload (genlmsg_total_size()), but then it does genlmsg_put()->nlmsg_put(). This means we forget to reserve a room for 'struct nlmsghdr'. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Thomas Graf <tgraf@suug.ch> Cc: Andrew Morton <akpm@osdl.org> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-29[PATCH] taskstats: fix sk_buff leakOleg Nesterov
'return genlmsg_cancel()' in taskstats_user_cmd/taskstats_exit_send potentially leaks a skb. Unless we pass 'rep_skb' to the netlink layer we own sk_buff. This means we should always do kfree_skb() on failure. [ Thomas acked and pointed out missing return value in original version ] Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Thomas Graf <tgraf@suug.ch> Cc: Andrew Morton <akpm@osdl.org> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] workqueue: update kerneldocAlan Stern
This patch (as812) changes the kerneldoc comments explaining the return values from queue_work(), queue_delayed_work(), and queue_delayed_work_on(). The updated comments explain more accurately the meaning of the return code and avoid suggesting that a 0 value means the routine was unsuccessful. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] cpu-hotplug: release `workqueue_mutex' properly on CPU hot-removeSatoru Takeuchi
_cpu_down() acquires `workqueue_mutex' on its process, but doen't release it if __cpu_disable() fails. Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] time_adjust cleared before useJim Houston
I notice that the code which implements adjtime clears the time_adjust value before using it. The attached patch makes the obvious fix. Acked-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Jim Houston <jim.houston@ccur.com> Cc: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] fill_tgid: cleanup delays accountingOleg Nesterov
fill_tgid() should skip not only an already exited group leader. If the task has ->exit_state != 0 it already did exit_notify(), so it also did fill_tgid_exit()->delayacct_add_tsk(->signal->stats) and we should skip it to avoid a double accounting. This patch doesn't close the race completely, but it cleanups the code. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] taskstats: don't use tasklist_lockOleg Nesterov
Remove tasklist_lock from taskstats.c. find_task_by_pid() is rcu-safe. ->siglock allows us to traverse subthread without tasklist. Q: delay accounting looks wrong to me. If sub-thread has already called taskstats_exit_send() but didn't call release_task(self) yet it will be accounted twice. The window is big. No? Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] taskstats: kill ->taskstats_lock in favor of ->siglockOleg Nesterov
signal_struct is (mostly) protected by ->sighand->siglock, I think we don't need ->taskstats_lock to protect ->stats. This also allows us to simplify the locking in fill_tgid(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] taskstats_tgid_free: fix usageOleg Nesterov
taskstats_tgid_free() is called on copy_process's error path. This is wrong. IF (clone_flags & CLONE_THREAD) We should not clear ->signal->taskstats, current uses it, it probably has a valid accumulated info. ELSE taskstats_tgid_init() set ->signal->taskstats = NULL, there is nothing to free. Move the callsite to __exit_signal(). We don't need any locking, entire thread group is exiting, nobody should have a reference to soon to be released ->signal. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] bacct_add_tsk: fix unsafe and wrong parent/group_leader dereferenceOleg Nesterov
1. ts = timespec_sub(uptime, current->group_leader->start_time); It is possible that current != tsk. Probably it was supposed to be 'tsk->group_leader->start_time. But why we are reading group_leader's start_time ? This accounting is per thread, not per procees, I changed this to 'tsk->start_time. Please corect me. 2. stats->ac_ppid = (tsk->parent) ? tsk->parent->pid : 0; tsk->parent never == NULL, and it is unsafe to dereference it. Both the task and it's parent may exit after the caller unlocks tasklist_lock, the memory could be unmapped (DEBUG_SLAB). (And we should use ->real_parent->tgid in fact). Q: I don't understand the 'if (thread_group_leader(tsk))' check. Why it is needed ? Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] fill_tgid: fix task_struct leak and possible oopsOleg Nesterov
1. fill_tgid() forgets to do put_task_struct(first). 2. release_task(first) can happen after fill_tgid() drops tasklist_lock, it is unsafe to dereference first->signal. This is a temporary fix, imho the locking should be reworked. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] Constify compat_get_bitmap argumentStephen Rothwell
This means we can call it when the bitmap we want to fetch is declared const. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28[PATCH] Add missing space in module.c for taintskernelJan Dittmer
Obvious fix. Signed-off-by: Jan Dittmer <jdi@l4x.org> Acked-by: Florin Malita <fmalita@gmail.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-21[PATCH] x86-64: Speed up dwarf2 unwinderJan Beulich
This changes the dwarf2 unwinder to do a binary search for CIEs instead of a linear work. The linker is unfortunately not able to build a proper lookup table at link time, instead it creates one at runtime as soon as the bootmem allocator is usable (so you'll continue using the linear lookup for the first [hopefully] few calls). The code should be ready to utilize a build-time created table once a fixed linker becomes available. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
2006-10-20[PATCH] kernel/nsproxy.c: use kmemdup()Alexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20[PATCH] cad_pid sysctl with PROC_FS=nRandy Dunlap
If CONFIG_PROC_FS=n: kernel/sysctl.c:148: warning: 'proc_do_cad_pid' used but never defined kernel/built-in.o:(.data+0x1228): undefined reference to `proc_do_cad_pid' make: *** [.tmp_vmlinux1] Error 1 Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20[PATCH] readjust comments of task_timeslice for kernel docBorislav Petkov
Signed-off-by: Borislav Petkov <petkov@math.uni-muenster.de> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/dtor/inputLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: fm801-gp - handle errors from pci_enable_device() Input: gameport core - handle errors returned by device_bind_driver() Input: serio core - handle errors returned by device_bind_driver() Lockdep: fix compile error in drivers/input/serio/serio.c Input: serio - add lockdep annotations Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass() Input: atkbd - supress "too many keys" error message Input: i8042 - supress ACK/NAKs when blinking during panic Input: add missing exports to fix modular build
2006-10-17[PATCH] Convert cpu hotplug notifiers to use raw_notifier instead of ↵Neil Brown
blocking_notifier The use of blocking notifier by _cpu_up and _cpu_down in cpu.c has two problem. 1/ An interaction with the workqueue notifier causes lockdep to spit a warning. 2/ A notifier could conceivable be added or removed while _cpu_up or _cpu_down are in process. As each notifier is called twice (prepare then commit/abort) this could be unhealthy. To fix to we simply take cpu_add_remove_lock while adding or removing notifiers to/from the list. This makes the 'blocking' usage unnecessary as all accesses to cpu_chain are now protected by cpu_add_remove_lock. So change "blocking" to "raw" in all relevant places. This fixes 1. Credit: Andrew Morton Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> (reporter) Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17[PATCH] rt-mutex: fixup rt-mutex debug codePeter Zijlstra
BUG: warning at kernel/rtmutex-debug.c:125/rt_mutex_debug_task_free() (Not tainted) [<c04051e3>] show_trace_log_lvl+0x58/0x16a [<c04057f0>] show_trace+0xd/0x10 [<c0405900>] dump_stack+0x19/0x1b [<c043f03d>] rt_mutex_debug_task_free+0x35/0x6a [<c04224c0>] free_task+0x15/0x24 [<c042378c>] copy_process+0x12bd/0x1324 [<c0423835>] do_fork+0x42/0x113 [<c04021dd>] sys_fork+0x19/0x1b [<c0403fb7>] syscall_call+0x7/0xb In copy_process(), dup_task_struct() also duplicates the ->pi_lock, ->pi_waiters and ->pi_blocked_on members. rt_mutex_debug_task_free() called from free_task() validates these members. However free_task() can be invoked before these members are reset for the new task. Move the initialization code before the first bail that can hit free_task(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17[PATCH] genirq: clean up irq-flow-type namingIngo Molnar
Introduce desc->name and eliminate the handle_irq_name() hack. Add set_irq_chip_and_handler_name() to set the flow type and name at once. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Matthew Wilcox <willy@debian.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17[PATCH] swsusp: fix memory leaksAndrew Morton
My fancy new swsusp IO code had a big memory leak. It's somewhat invisible because the whole mem_map[] gets overwritten after resume, but it can cause us to get low on memory during the actual suspend process. Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17[PATCH] posix-cpu-timers: prevent signal delivery starvationThomas Gleixner
The integer divisions in the timer accounting code can round the result down to 0. Adding 0 is without effect and the signal delivery stops. Clamp the division result to minimum 1 to avoid this. Problem was reported by Seongbae Park <spark@google.com>, who provided also an inital patch. Roland sayeth: I have had some more time to think about the problem, and to reproduce it using Toyo's test case. For the record, if my understanding of the problem is correct, this happens only in one very particular case. First, the expiry time has to be so soon that in cputime_t units (usually 1s/HZ ticks) it's < nthreads so the division yields zero. Second, it only affects each thread that is so new that its CPU time accumulation is zero so now+0 is still zero and ->it_*_expires winds up staying zero. For the VIRT and PROF clocks when cputime_t is tick granularity (or the SCHED clock on configurations where sched_clock's value only advances on clock ticks), this is not hard to arrange with new threads starting up and blocking before they accumulate a whole tick of CPU time. That's what happens in Toyo's test case. Note that in general it is fine for that division to round down to zero, and set each thread's expiry time to its "now" time. The problem only arises with thread's whose "now" value is still zero, so that now+0 winds up 0 and is interpreted as "not set" instead of ">= now". So it would be a sufficient and more precise fix to just use max(ticks, 1) inside the loop when setting each it_*_expires value. But, it does no harm to round the division up to one and always advance every thread's expiry time. If the thread didn't already fire timers for the expiry time of "now", there is no expectation that it will do so before the next tick anyway. So I followed Thomas's patch in lifting the max out of the loops. This patch also covers the reload cases, which are harder to write a test for (and I didn't try). I've tested it with Toyo's case and it fixes that. [toyoa@mvista.com: fix: min_t -> max_t] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Daniel Walker <dwalker@mvista.com> Cc: Toyo Abe <toyoa@mvista.com> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Seongbae Park <spark@google.com> Cc: Peter Mattis <pmattis@google.com> Cc: Rohit Seth <rohitseth@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17[PATCH] i386 Time: Avoid PIT SMP lockupsjohn stultz
Avoid possible PIT livelock issues seen on SMP systems (and reported by Andi), by not allowing it as a clocksource on SMP boxes. However, since the PIT may no longer be present, we have to properly handle the cases where SMP systems have TSC skew and fall back from the TSC. Since the PIT isn't there, it would "fall back" to the TSC again. So this changes the jiffies rating to 1, and the TSC-bad rating value to 0. Thus you will get the following behavior priority on i386 systems: tsc [if present & stable] hpet [if present] cyclone [if present] acpi_pm [if present] pit [if UP] jiffies Rather then the current more complicated: tsc [if present & stable] hpet [if present] cyclone [if present] acpi_pm [if present] pit [if cpus < 4] tsc [if present & unstable] jiffies Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17[PATCH] lockdep: increase max allowed recursion depthIngo Molnar
In general, lockdep warnings are intended to be non-fatal, so I have put in various practical limits on internal data structure failure modes. We haven't had a /single/ lockdep-internal crash ever since lockdep went upstream [the unwinder crashes are outside of lockdep], and that's largely due to the good internal checks it does. Recursion within the dependency graph is currently limited to 20, that's probably not enough on some many-CPU boxes - this patch doubles it to 40. I have written the lockdep functions to have as small stackframes as possible, so 40 should be OK too. (The practical recursion limit should be somewhere between 100 and 200 entries. If we hit that then I'll change the algorithm to be iteration-based. Graph walking logic is so easy to program via recursion, so i'd like to keep recursion as long as possible.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-16[PATCH] fix epoll_pwait when EPOLL=nRandy Dunlap
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=7371 sys_epoll_pwait needs to be listed as a conditional (weak) entry point for CONFIG_EPOLL=n. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] lockdep: fix printk recursion logicIngo Molnar
Bug reported and fixed by Tilman Schmidt <tilman@imap.cc>: if lockdep is enabled then log messages make it to /var/log/messages belatedly. The reason is a missed wakeup of klogd. Initially there was only a lockdep_internal() protection against lockdep recursion within vprintk() - it grew the 'outer' lockdep_off()/on() protection only later on. But that lockdep_off() made the release_console_sem() within vprintk() always happen under the lockdep_internal() condition, causing the bug. The right solution to remove the inner protection against recursion here - the outer one is enough. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Tilman Schmidt <tilman@imap.cc> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] lockdep: use BUILD_BUG_ONAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] bitmap: parse input from kernel and user buffersReinette Chatre
lib/bitmap.c:bitmap_parse() is a library function that received as input a user buffer. This seemed to have originated from the way the write_proc function of the /proc filesystem operates. This has been reworked to not use kmalloc and eliminates a lot of get_user() overhead by performing one access_ok before using __get_user(). We need to test if we are in kernel or user space (is_user) and access the buffer differently. We cannot use __get_user() to access kernel addresses in all cases, for example in architectures with separate address space for kernel and user. This function will be useful for other uses as well; for example, taking input for /sysfs instead of /proc, so it was changed to accept kernel buffers. We have this use for the Linux UWB project, as part as the upcoming bandwidth allocator code. Only a few routines used this function and they were changed too. Signed-off-by: Reinette Chatre <reinette.chatre@linux.intel.com> Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com> Cc: Paul Jackson <pj@sgi.com> Cc: Joe Korty <joe.korty@ccur.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] sched: likely profilingNick Piggin
This likely profiling is pretty fun. I found a few possible problems in sched.c. This patch may be not measurable, but when I did measure long ago, nooping (un)likely cost a couple of % on scheduler heavy benchmarks, so it all adds up. Tweak some branch hints: - the 2nd 64 bits in the bitmask is likely to be populated, because it contains the first 28 bits (nearly 3/4) of the normal priorities. (ratio of 669669:691 ~= 1000:1). - it isn't unlikely that context switching switches to another process. it might be very rapidly switching to and from the idle process (ratio of 475815:419004 and 471330:423544). Let the branch predictor decide. - preempt_enable seems to be very often called in a nested preempt_disable or with interrupts disabled (ratio of 3567760:87965 ~= 40:1) Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Daniel Walker <dwalker@mvista.com> Cc: Hua Zhong <hzhong@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] fix Module taint flags listing in Oops/panicFlorin Malita
Module taint flags listing in Oops/panic has a couple of issues: * taint_flags() doesn't null-terminate the buffer after printing the flags * per-module taints are only set if the kernel is not already tainted (with that particular flag) => only the first offending module gets its taint info correctly updated Some additional changes: * 'license_gplok' is no longer needed - equivalent to !(taints & TAINT_PROPRIETARY_MODULE) - so we can drop it from struct module * exporting module taint info via /proc/module: pwc 88576 0 - Live 0xf8c32000 evilmod 6784 1 pwc, Live 0xf8bbf000 (PF) Signed-off-by: Florin Malita <fmalita@gmail.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] mm: kevent threads: use MPOL_DEFAULTChristoph Lameter
Switch the memory policy of the kevent threads to MPOL_DEFAULT while leaving the kzalloc of the workqueue structure on interleave. This means that all code executed in the context of the kevent thread is allocating node local. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Alok Kataria <alok.kataria@calsoftinc.com> Cc: Andi Kleen <ak@suse.de> Cc: <pj@sgi.com> Cc: <shai@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] swsusp: Use suspend_consoleRafael J. Wysocki
Add suspend_console() and resume_console() to the suspend-to-disk code paths so that the users of netconsole can use swsusp with it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass()Peter Zijlstra
This annotation makes it possible to assign a subclass on lock init. This annotation is meant to reduce the _nested() annotations by assigning a default subclass. One could do without this annotation and rely on lockdep_set_class() exclusively, but that would require a manual stack of struct lock_class_key objects. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2006-10-10[PATCH] cpuset ANSI prototypeAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Paul Jackson <pj@sgi.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-10[PATCH] make kernel/relay.c __user-cleanAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-10[PATCH] __user annotations: futexAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>