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* [PATCH] task delay accounting fixesShailabh Nagar2006-09-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cleanup allocation and freeing of tsk->delays used by delay accounting. This solves two problems reported for delay accounting: 1. oops in __delayacct_blkio_ticks http://www.uwsg.indiana.edu/hypermail/linux/kernel/0608.2/1844.html Currently tsk->delays is getting freed too early in task exit which can cause a NULL tsk->delays to get accessed via reading of /proc/<tgid>/stats. The patch fixes this problem by freeing tsk->delays closer to when task_struct itself is freed up. As a result, it also eliminates the use of tsk->delays_lock which was only being used (inadequately) to safeguard access to tsk->delays while a task was exiting. 2. Possible memory leak in kernel/delayacct.c http://www.uwsg.indiana.edu/hypermail/linux/kernel/0608.2/1389.html The patch cleans up tsk->delays allocations after a bad fork which was missing earlier. The patch has been tested to fix the problems listed above and stress tested with rapid calls to delay accounting's taskstats command interface (which is the other path that can access the same data, besides the /proc interface causing the oops above). Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] ptrace: make pid of child process available for PTRACE_EVENT_VFORK_DONEChuck Ebbert2006-08-06
| | | | | | | | | | | | | | When delivering PTRACE_EVENT_VFORK_DONE, provide pid of the child process when tracer calls ptrace(PTRACE_GETEVENTMSG). This is already (accidentally) available when the tracer is tracing VFORK in addition to VFORK_DONE. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Cc: Daniel Jacobowitz <dan@debian.org> Cc: Albert Cahalan <acahalan@gmail.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] delay accounting taskstats interface send tgid onceShailabh Nagar2006-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Send per-tgid data only once during exit of a thread group instead of once with each member thread exit. Currently, when a thread exits, besides its per-tid data, the per-tgid data of its thread group is also sent out, if its thread group is non-empty. The per-tgid data sent consists of the sum of per-tid stats for all *remaining* threads of the thread group. This patch modifies this sending in two ways: - the per-tgid data is sent only when the last thread of a thread group exits. This cuts down heavily on the overhead of sending/receiving per-tgid data, especially when other exploiters of the taskstats interface aren't interested in per-tgid stats - the semantics of the per-tgid data sent are changed. Instead of being the sum of per-tid data for remaining threads, the value now sent is the true total accumalated statistics for all threads that are/were part of the thread group. The patch also addresses a minor issue where failure of one accounting subsystem to fill in the taskstats structure was causing the send of taskstats to not be sent at all. The patch has been tested for stability and run cerberus for over 4 hours on an SMP. [akpm@osdl.org: bugfixes] Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] per-task-delay-accounting: setupShailabh Nagar2006-07-15
| | | | | | | | | | | | | | | | | | Initialization code related to collection of per-task "delay" statistics which measure how long it had to wait for cpu, sync block io, swapping etc. The collection of statistics and the interface are in other patches. This patch sets up the data structures and allows the statistics collection to be disabled through a kernel boot parameter. Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Balbir Singh <balbir@in.ibm.com> Cc: Jes Sorensen <jes@sgi.com> Cc: Peter Chubb <peterc@gelato.unsw.edu.au> Cc: Erich Focht <efocht@ess.nec.de> Cc: Levent Serinol <lserinol@gmail.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove the tasklist_lock exportChristoph Hellwig2006-07-10
| | | | | | | | | As announced half a year ago this patch will remove the tasklist_lock export. The previous two patches got rid of the remaining modular users. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sched: cleanup, remove task_t, convert to struct task_structIngo Molnar2006-07-03
| | | | | | | | | | | | cleanup: remove task_t and convert all the uses to struct task_struct. I introduced it for the scheduler anno and it was a mistake. Conversion was mostly scripted, the result was reviewed and all secondary whitespace and style impact (if any) was fixed up by hand. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: annotate ->mmap_semIngo Molnar2006-07-03
| | | | | | | | | | Teach special (recursive) locking code to the lock validator. Has no effect on non-lockdep kernels. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: coreIngo Molnar2006-07-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do 'make oldconfig' and accept all the defaults for new config options - reboot into the kernel and if everything goes well it should boot up fine and you should have /proc/lockdep and /proc/lockdep_stats files. Typically if the lock validator finds some problem it will print out voluminous debug output that begins with "BUG: ..." and which syslog output can be used by kernel developers to figure out the precise locking scenario. What does the lock validator do? It "observes" and maps all locking rules as they occur dynamically (as triggered by the kernel's natural use of spinlocks, rwlocks, mutexes and rwsems). Whenever the lock validator subsystem detects a new locking scenario, it validates this new rule against the existing set of rules. If this new rule is consistent with the existing set of rules then the new rule is added transparently and the kernel continues as normal. If the new rule could create a deadlock scenario then this condition is printed out. When determining validity of locking, all possible "deadlock scenarios" are considered: assuming arbitrary number of CPUs, arbitrary irq context and task context constellations, running arbitrary combinations of all the existing locking scenarios. In a typical system this means millions of separate scenarios. This is why we call it a "locking correctness" validator - for all rules that are observed the lock validator proves it with mathematical certainty that a deadlock could not occur (assuming that the lock validator implementation itself is correct and its internal data structures are not corrupted by some other kernel subsystem). [see more details and conditionals of this statement in include/linux/lockdep.h and Documentation/lockdep-design.txt] Furthermore, this "all possible scenarios" property of the validator also enables the finding of complex, highly unlikely multi-CPU multi-context races via single single-context rules, increasing the likelyhood of finding bugs drastically. In practical terms: the lock validator already found a bug in the upstream kernel that could only occur on systems with 3 or more CPUs, and which needed 3 very unlikely code sequences to occur at once on the 3 CPUs. That bug was found and reported on a single-CPU system (!). So in essence a race will be found "piecemail-wise", triggering all the necessary components for the race, without having to reproduce the race scenario itself! In its short existence the lock validator found and reported many bugs before they actually caused a real deadlock. To further increase the efficiency of the validator, the mapping is not per "lock instance", but per "lock-class". For example, all struct inode objects in the kernel have inode->inotify_mutex. If there are 10,000 inodes cached, then there are 10,000 lock objects. But ->inotify_mutex is a single "lock type", and all locking activities that occur against ->inotify_mutex are "unified" into this single lock-class. The advantage of the lock-class approach is that all historical ->inotify_mutex uses are mapped into a single (and as narrow as possible) set of locking rules - regardless of how many different tasks or inode structures it took to build this set of rules. The set of rules persist during the lifetime of the kernel. To see the rough magnitude of checking that the lock validator does, here's a portion of /proc/lockdep_stats, fresh after bootup: lock-classes: 694 [max: 2048] direct dependencies: 1598 [max: 8192] indirect dependencies: 17896 all direct dependencies: 16206 dependency chains: 1910 [max: 8192] in-hardirq chains: 17 in-softirq chains: 105 in-process chains: 1065 stack-trace entries: 38761 [max: 131072] combined max dependencies: 2033928 hardirq-safe locks: 24 hardirq-unsafe locks: 176 softirq-safe locks: 53 softirq-unsafe locks: 137 irq-safe locks: 59 irq-unsafe locks: 176 The lock validator has observed 1598 actual single-thread locking patterns, and has validated all possible 2033928 distinct locking scenarios. More details about the design of the lock validator can be found in Documentation/lockdep-design.txt, which can also found at: http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt [bunk@stusta.de: cleanups] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.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>
* [PATCH] lockdep: irqtrace subsystem, coreIngo Molnar2006-07-03
| | | | | | | | | | | | Accurate hard-IRQ-flags and softirq-flags state tracing. This allows us to attach extra functionality to IRQ flags on/off events (such as trace-on/off). Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: better lock debuggingIngo Molnar2006-07-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generic lock debugging: - generalized lock debugging framework. For example, a bug in one lock subsystem turns off debugging in all lock subsystems. - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from the mutex/rtmutex debugging code: it caused way too much prototype hackery, and lockdep will give the same information anyway. - ability to do silent tests - check lock freeing in vfree too. - more finegrained debugging options, to allow distributions to turn off more expensive debugging features. There's no separate 'held mutexes' list anymore - but there's a 'held locks' stack within lockdep, which unifies deadlock detection across all lock classes. (this is independent of the lockdep validation stuff - lockdep first checks whether we are holding a lock already) Here are the current debugging options: CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y which do: config DEBUG_MUTEXES bool "Mutex debugging, basic checks" config DEBUG_LOCK_ALLOC bool "Detect incorrect freeing of live mutexes" Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-30
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] pi-futex: futex_lock_pi/futex_unlock_pi supportIngo Molnar2006-06-27
| | | | | | | | | | | | This adds the actual pi-futex implementation, based on rt-mutexes. [dino@in.ibm.com: fix an oops-causing race] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Dinakar Guniguntala <dino@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pi-futex: rt mutex coreIngo Molnar2006-06-27
| | | | | | | | | | Core functions for the rt-mutex subsystem. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] coredump: copy_process: don't check SIGNAL_GROUP_EXITOleg Nesterov2006-06-26
| | | | | | | | | | | After the previous patch SIGNAL_GROUP_EXIT implies a pending SIGKILL, we can remove this check from copy_process() because we already checked !signal_pending(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] proc: Rewrite the proc dentry flush on exit optimizationEric W. Biederman2006-06-26
| | | | | | | | | | | | | | | | To keep the dcache from filling up with dead /proc entries we flush them on process exit. However over the years that code has gotten hairy with a dentry_pointer and a lock in task_struct and misdocumented as a correctness feature. I have rewritten this code to look and see if we have a corresponding entry in the dcache and if so flush it on process exit. This removes the extra fields in the task_struct and allows me to trivially handle the case of a /proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pacct: add pacct_struct to fix some pacct bugs.KaiGai Kohei2006-06-25
| | | | | | | | | | | The pacct facility need an i/o operation when an accounting record is generated. There is a possibility to wake OOM killer up. If OOM killer is activated, it kills some processes to make them release process memory regions. But acct_process() is called in the killed processes context before calling exit_mm(), so those processes cannot release own memory. In the results, any processes stop in this point and it finally cause a system stall.
* [PATCH] dup fd error fixPrasanna Meda2006-06-23
| | | | | | | | Set errorp in dup_fd, it will be used in sys_unshare also. Signed-off-by: Prasanna Meda <mlp@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mmput() might sleepAndrew Morton2006-06-23
| | | | | | | | | exit_aio() and exit_mmap() can sleep. But it's easy to accidentally call mmput() from inside locks. Cc: Dave Peterson <dsp@llnl.gov> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] move call of audit_free() into do_exit()Al Viro2006-05-01
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] Don't inherit ->splice_pipe across forksJens Axboe2006-04-20
| | | | | | | It's really task private, so clear that field on fork after copying task structure. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] task: Make task list manipulations RCU safeEric W. Biederman2006-04-19
| | | | | | | | | | | | | | | | | While we can currently walk through thread groups, process groups, and sessions with just the rcu_read_lock, this opens the door to walking the entire task list. We already have all of the other RCU guarantees so there is no cost in doing this, this should be enough so that proc can stop taking the tasklist lock during readdir. prev_task was killed because it has no users, and using it will miss new tasks when doing an rcu traversal. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kill unushed __put_task_struct_cbEric W. Biederman2006-04-14
| | | | | | | | | | | | | | | Somehow in the midst of dotting i's and crossing t's during the merge up to rc1 we wound up keeping __put_task_struct_cb when it should have been killed as it no longer has any users. Sorry I probably should have caught this while it was still in the -mm tree. Having the old code there gets confusing when reading through the code and trying to understand what is happening. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] wrong error path in dup_fd() leading to oopses in RCUKirill Korotaev2006-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | Wrong error path in dup_fd() - it should return NULL on error, not an address of already freed memory :/ Triggered by OpenVZ stress test suite. What is interesting is that it was causing different oopses in RCU like below: Call Trace: [<c013492c>] rcu_do_batch+0x2c/0x80 [<c0134bdd>] rcu_process_callbacks+0x3d/0x70 [<c0126cf3>] tasklet_action+0x73/0xe0 [<c01269aa>] __do_softirq+0x10a/0x130 [<c01058ff>] do_softirq+0x4f/0x60 ======================= [<c0113817>] smp_apic_timer_interrupt+0x77/0x110 [<c0103b54>] apic_timer_interrupt+0x1c/0x24 Code: Bad EIP value. <0>Kernel panic - not syncing: Fatal exception in interrupt Signed-Off-By: Pavel Emelianov <xemul@sw.ru> Signed-Off-By: Dmitry Mishin <dim@openvz.org> Signed-Off-By: Kirill Korotaev <dev@openvz.org> Signed-Off-By: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pidhash: Refactor the pid hash tableEric W. Biederman2006-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Simplifies the code, reduces the need for 4 pid hash tables, and makes the code more capable. In the discussions I had with Oleg it was felt that to a large extent the cleanup itself justified the work. With struct pid being dynamically allocated meant we could create the hash table entry when the pid was allocated and free the hash table entry when the pid was freed. Instead of playing with the hash lists when ever a process would attach or detach to a process. For myself the fact that it gave what my previous task_ref patch gave for free with simpler code was a big win. The problem is that if you hold a reference to struct task_struct you lock in 10K of low memory. If you do that in a user controllable way like /proc does, with an unprivileged but hostile user space application with typical resource limits of 1000 fds and 100 processes I can trigger the OOM killer by consuming all of low memory with task structs, on a machine wight 1GB of low memory. If I instead hold a reference to struct pid which holds a pointer to my task_struct, I don't suffer from that problem because struct pid is 2 orders of magnitude smaller. In fact struct pid is small enough that most other kernel data structures dwarf it, so simply limiting the number of referring data structures is enough to prevent exhaustion of low memory. This splits the current struct pid into two structures, struct pid and struct pid_link, and reduces our number of hash tables from PIDTYPE_MAX to just one. struct pid_link is the per process linkage into the hash tables and lives in struct task_struct. struct pid is given an indepedent lifetime, and holds pointers to each of the pid types. The independent life of struct pid simplifies attach_pid, and detach_pid, because we are always manipulating the list of pids and not the hash table. In addition in giving struct pid an indpendent life it makes the concept much more powerful. Kernel data structures can now embed a struct pid * instead of a pid_t and not suffer from pid wrap around problems or from keeping unnecessarily large amounts of memory allocated. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] resurrect __put_task_structAndrew Morton2006-03-31
| | | | | | | | This just got nuked in mainline. Bring it back because Eric's patches use it. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cleanup __exit_signal->cleanup_sighand pathOleg Nesterov2006-03-28
| | | | | | | | | | | Move 'tsk->sighand = NULL' from cleanup_sighand() to __exit_signal(). This makes the exit path more understandable and allows us to do cleanup_sighand() outside of ->siglock protected section. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make fork() atomic wrt pgrp/session signalsOleg Nesterov2006-03-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eric W. Biederman wrote: > > Ok. SUSV3/Posix is clear, fork is atomic with respect > to signals. Either a signal comes before or after a > fork but not during. (See the rationale section). > http://www.opengroup.org/onlinepubs/000095399/functions/fork.html > > The tasklist_lock does not stop forks from adding to a process > group. The forks stall while the tasklist_lock is held, but a fork > that began before we grabbed the tasklist_lock simply completes > afterwards, and the child does not receive the signal. This also means that SIGSTOP or sig_kernel_coredump() signal can't be delivered to pgrp/session reliably. With this patch copy_process() returns -ERESTARTNOINTR when it detects a pending signal, fork() will be restarted transparently after handling the signals. This patch also deletes now unneeded "group_stop_count > 0" check, copy_process() can no longer succeed while group stop in progress. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pids: kill PIDTYPE_TGIDOleg Nesterov2006-03-28
| | | | | | | | | | | | | | | | | | | | | This patch kills PIDTYPE_TGID pid_type thus saving one hash table in kernel/pid.c and speeding up subthreads create/destroy a bit. It is also a preparation for the further tref/pids rework. This patch adds 'struct list_head thread_group' to 'struct task_struct' instead. We don't detach group leader from PIDTYPE_PID namespace until another thread inherits it's ->pid == ->tgid, so we are safe wrt premature free_pidmap(->tgid) call. Currently there are no users of find_task_by_pid_type(PIDTYPE_TGID). Should the need arise, we can use find_task_by_pid()->group_leader. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] rename __exit_sighand to cleanup_sighandOleg Nesterov2006-03-28
| | | | | | | | | | | | | | Cosmetic, rename __exit_sighand to cleanup_sighand and move it close to copy_sighand(). This matches copy_signal/cleanup_signal naming, and I think it is easier to follow. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] copy_process: cleanup bad_fork_cleanup_signalOleg Nesterov2006-03-28
| | | | | | | | | | | | | | | | | | | | | | | | __exit_signal() does important cleanups atomically under ->siglock. It is also called from copy_process's error path. This is not good, for example we can't move __unhash_process() under ->siglock for that reason. We should not mix these 2 paths, just look at ugly 'if (p->sighand)' under 'bad_fork_cleanup_sighand:' label. For copy_process() case it is sufficient to just backout copy_signal(), nothing more. Again, nobody can see this task yet. For CLONE_THREAD case we just decrement signal->count, otherwise nobody can see this ->signal and we can free it lockless. This patch assumes it is safe to do exit_thread_group_keys() without tasklist_lock. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: David Howells <dhowells@redhat.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>
* [PATCH] copy_process: cleanup bad_fork_cleanup_sighandOleg Nesterov2006-03-28
| | | | | | | | | | | | | | | | | | | | | | The only caller of exit_sighand(tsk) is copy_process's error path. We can call __exit_sighand() directly and kill exit_sighand(). This 'tsk' was not yet registered in pid_hash[] or init_task.tasks, it has no external references, nobody can see it, and IF (clone_flags & CLONE_SIGHAND) At least 'current' has a reference to ->sighand, this means atomic_dec_and_test(sighand->count) can't be true. ELSE Nobody can see this ->sighand, this means we can free it without any locking. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] convert sighand_cache to use SLAB_DESTROY_BY_RCUOleg Nesterov2006-03-28
| | | | | | | | | | | | | | | | | | This patch borrows a clever Hugh's 'struct anon_vma' trick. Without tasklist_lock held we can't trust task->sighand until we locked it and re-checked that it is still the same. But this means we don't need to defer 'kmem_cache_free(sighand)'. We can return the memory to slab immediately, all we need is to be sure that sighand->siglock can't dissapear inside rcu protected section. To do so we need to initialize ->siglock inside ctor function, SLAB_DESTROY_BY_RCU does the rest. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pidhash: don't count idle threadsOleg Nesterov2006-03-28
| | | | | | | | | | | | | | | | | | | | | | | | | fork_idle() does unhash_process() just after copy_process(). Contrary, boot_cpu's idle thread explicitely registers itself for each pid_type with nr = 0. copy_process() already checks p->pid != 0 before process_counts++, I think we can just skip attach_pid() calls and job control inits for idle threads and kill unhash_process(). We don't need to cleanup ->proc_dentry in fork_idle() because with this patch idle threads are never hashed in kernel/pid.c:pid_hash[]. We don't need to hash pid == 0 in pidmap_init(). free_pidmap() is never called with pid == 0 arg, so it will never be reused. So it is still possible to use pid == 0 in any PIDTYPE_xxx namespace from kernel/pid.c's POV. However with this patch we don't hash pid == 0 for PIDTYPE_PID case. We still have have PIDTYPE_PGID/PIDTYPE_SID entries with pid == 0: /sbin/init and kernel threads which don't call daemonize(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kill SET_LINKS/REMOVE_LINKSOleg Nesterov2006-03-28
| | | | | | | | | | | | | | Both SET_LINKS() and SET_LINKS/REMOVE_LINKS() have exactly one caller, and these callers already check thread_group_leader(). This patch kills theese macros, they mix two different things: setting process's parent and registering it in init_task.tasks list. Callers are updated to do these actions by hand. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lightweight robust futexes updatesIngo Molnar2006-03-27
| | | | | | | | | | | | | | | | | | - fix: initialize the robust list(s) to NULL in copy_process. - doc update - cleanup: rename _inuser to _inatomic - __user cleanups and other small cleanups Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds2006-03-26
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: drivers/char/ftape/lowlevel/fdc-io.c: Correct a comment Kconfig help: MTD_JEDECPROBE already supports Intel Remove ugly debugging stuff do_mounts.c: Minor ROOT_DEV comment cleanup BUG_ON() Conversion in drivers/s390/block/dasd_devmap.c BUG_ON() Conversion in mm/mempool.c BUG_ON() Conversion in mm/memory.c BUG_ON() Conversion in kernel/fork.c BUG_ON() Conversion in ipc/sem.c BUG_ON() Conversion in fs/ext2/ BUG_ON() Conversion in fs/hfs/ BUG_ON() Conversion in fs/dcache.c BUG_ON() Conversion in fs/buffer.c BUG_ON() Conversion in input/serio/hp_sdc_mlc.c BUG_ON() Conversion in md/dm-table.c BUG_ON() Conversion in md/dm-path-selector.c BUG_ON() Conversion in drivers/isdn BUG_ON() Conversion in drivers/char BUG_ON() Conversion in drivers/mtd/
| * BUG_ON() Conversion in kernel/fork.cEric Sesterhenn2006-03-26
| | | | | | | | | | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* | [PATCH] hrtimers: remove data fieldRoman Zippel2006-03-26
|/ | | | | | | | | | | | The nanosleep cleanup allows to remove the data field of hrtimer. The callback function can use container_of() to get it's own data. Since the hrtimer structure is anyway embedded in other structures, this adds no overhead. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpuset memory spread slab cache optimizationsPaul Jackson2006-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | The hooks in the slab cache allocator code path for support of NUMA mempolicies and cpuset memory spreading are in an important code path. Many systems will use neither feature. This patch optimizes those hooks down to a single check of some bits in the current tasks task_struct flags. For non NUMA systems, this hook and related code is already ifdef'd out. The optimization is done by using another task flag, set if the task is using a non-default NUMA mempolicy. Taking this flag bit along with the PF_SPREAD_PAGE and PF_SPREAD_SLAB flag bits added earlier in this 'cpuset memory spreading' patch set, one can check for the combination of any of these special case memory placement mechanisms with a single test of the current tasks task_struct flags. This patch also tightens up the code, to save a few bytes of kernel text space, and moves some of it out of line. Due to the nested inlines called from multiple places, we were ending up with three copies of this code, which once we get off the main code path (for local node allocation) seems a bit wasteful of instruction memory. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23Jens Axboe2006-03-23
| | | | Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] Shrinks sizeof(files_struct) and better layoutEric Dumazet2006-03-23
| | | | | | | | | | | | | | | | | | | | | | | | 1) Reduce the size of (struct fdtable) to exactly 64 bytes on 32bits platforms, lowering kmalloc() allocated space by 50%. 2) Reduce the size of (files_struct), using a special 32 bits (or 64bits) embedded_fd_set, instead of a 1024 bits fd_set for the close_on_exec_init and open_fds_init fields. This save some ram (248 bytes per task) as most tasks dont open more than 32 files. D-Cache footprint for such tasks is also reduced to the minimum. 3) Reduce size of allocated fdset. Currently two full pages are allocated, that is 32768 bits on x86 for example, and way too much. The minimum is now L1_CACHE_BYTES. UP and SMP should benefit from this patch, because most tasks will touch only one cache line when open()/close() stdin/stdout/stderr (0/1/2), (next_fd, close_on_exec_init, open_fds_init, fd_array[0 .. 2] being in the same cache line) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare: Error if passed unsupported flagsEric W. Biederman2006-03-22
| | | | | | | | | | | | A bare bones trivial patch to ensure we always get -EINVAL on the unsupported cases for sys_unshare. If this goes in before 2.6.16 it allows us to forward compatible with future applications using sys_unshare. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: JANAK DESAI <janak@us.ibm.com> Cc: <stable@kerenl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] disable unshare(CLONE_VM) for nowOleg Nesterov2006-03-18
| | | | | | | | | | | | | sys_unshare() does mmput(new_mm). This is not enough if we have mm->core_waiters. This patch is a temporary fix for soon to be released 2.6.16. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> [ Checked with Uli: "I'm not planning to use unshare(CLONE_VM). It's not needed for any functionality planned so far. What we (as in Red Hat) need unshare() for now is the filesystem side." ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare: Use rcu_assign_pointer when setting sighandEric W. Biederman2006-03-17
| | | | | | | | | | | | | | The sighand pointer only needs the rcu_read_lock on the read side. So only depending on task_lock protection when setting this pointer is not enough. We also need a memory barrier to ensure the initialization is seen first. Use rcu_assign_pointer as it does this for us, and clearly documents that we are setting an rcu readable pointer. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix sigaltstack corruption among cloned threadsGOTO Masanori2006-03-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes alternate signal stack corruption among cloned threads with CLONE_SIGHAND (and CLONE_VM) for linux-2.6.16-rc6. The value of alternate signal stack is currently inherited after a call of clone(... CLONE_SIGHAND | CLONE_VM). But if sigaltstack is set by a parent thread, and then if multiple cloned child threads (+ parent threads) call signal handler at the same time, some threads may be conflicted - because they share to use the same alternative signal stack region. Finally they get sigsegv. It's an undesirable race condition. Note that child threads created from NPTL pthread_create() also hit this conflict when the parent thread uses sigaltstack, without my patch. To fix this problem, this patch clears the child threads' sigaltstack information like exec(). This behavior follows the SUSv3 specification. In SUSv3, pthread_create() says "The alternate stack shall not be inherited (when new threads are initialized)". It means that sigaltstack should be cleared when sigaltstack memory space is shared by cloned threads with CLONE_SIGHAND. Note that I chose "if (clone_flags & CLONE_SIGHAND)" line because: - If clone_flags line is not existed, fork() does not inherit sigaltstack. - CLONE_VM is another choice, but vfork() does not inherit sigaltstack. - CLONE_SIGHAND implies CLONE_VM, and it looks suitable. - CLONE_THREAD is another candidate, and includes CLONE_SIGHAND + CLONE_VM, but this flag has a bit different semantics. I decided to use CLONE_SIGHAND. [ Changed to test for CLONE_VM && !CLONE_VFORK after discussion --Linus ] Signed-off-by: GOTO Masanori <gotom@sanori.org> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Linus Torvalds <torvalds@osdl.org> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove __put_task_struct_cb export againChristoph Hellwig2006-03-11
| | | | | | | | | | | | | | | | | | | The patch '[PATCH] RCU signal handling' [1] added an export for __put_task_struct_cb, a put_task_struct helper newly introduced in that patch. But the put_task_struct couldn't be used modular previously as __put_task_struct wasn't exported. There are not callers of it in modular code, and it shouldn't be exported because we don't want drivers to hold references to task_structs. This patch removes the export and folds __put_task_struct into __put_task_struct_cb as there's no other caller. [1] http://www2.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e56d090310d7625ecb43a1eeebd479f04affb48b Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix kill_proc_info() vs fork() theoretical raceOleg Nesterov2006-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | copy_process: attach_pid(p, PIDTYPE_PID, p->pid); attach_pid(p, PIDTYPE_TGID, p->tgid); What if kill_proc_info(p->pid) happens in between? copy_process() holds current->sighand.siglock, so we are safe in CLONE_THREAD case, because current->sighand == p->sighand. Otherwise, p->sighand is unlocked, the new process is already visible to the find_task_by_pid(), but have a copy of parent's 'struct pid' in ->pids[PIDTYPE_TGID]. This means that __group_complete_signal() may hang while doing do ... while (next_thread() != p) We can solve this problem if we reverse these 2 attach_pid()s: attach_pid() does wmb() group_send_sig_info() calls spin_lock(), which provides a read barrier. // Yes ? I don't think we can hit this race in practice, but still. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix kill_proc_info() vs CLONE_THREAD raceOleg Nesterov2006-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | There is a window after copy_process() unlocks ->sighand.siglock and before it adds the new thread to the thread list. In that window __group_complete_signal(SIGKILL) will not see the new thread yet, so this thread will start running while the whole thread group was supposed to exit. I beleive we have another good reason to place attach_pid(PID/TGID) under ->sighand.siglock. We can do the same for release_task()->__unhash_process() de_thread()->switch_exec_pids() After that we don't need tasklist_lock to iterate over the thread list, and we can simplify things, see for example do_sigaction() or sys_times(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: unshare filesJANAK DESAI2006-02-07
| | | | | | | | | | | | | | If the file descriptor structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: unshare vmJANAK DESAI2006-02-07
| | | | | | | | | | | | | | If vm structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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