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path: root/kernel/fork.c
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2006-04-20[PATCH] Don't inherit ->splice_pipe across forksJens Axboe
It's really task private, so clear that field on fork after copying task structure. Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-19[PATCH] task: Make task list manipulations RCU safeEric W. Biederman
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>
2006-04-14[PATCH] kill unushed __put_task_struct_cbEric W. Biederman
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>
2006-03-31[PATCH] wrong error path in dup_fd() leading to oopses in RCUKirill Korotaev
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>
2006-03-31[PATCH] pidhash: Refactor the pid hash tableEric W. Biederman
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>
2006-03-31[PATCH] resurrect __put_task_structAndrew Morton
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>
2006-03-28[PATCH] cleanup __exit_signal->cleanup_sighand pathOleg Nesterov
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>
2006-03-28[PATCH] make fork() atomic wrt pgrp/session signalsOleg Nesterov
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>
2006-03-28[PATCH] pids: kill PIDTYPE_TGIDOleg Nesterov
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>
2006-03-28[PATCH] rename __exit_sighand to cleanup_sighandOleg Nesterov
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>
2006-03-28[PATCH] copy_process: cleanup bad_fork_cleanup_signalOleg Nesterov
__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>
2006-03-28[PATCH] copy_process: cleanup bad_fork_cleanup_sighandOleg Nesterov
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>
2006-03-28[PATCH] convert sighand_cache to use SLAB_DESTROY_BY_RCUOleg Nesterov
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>
2006-03-28[PATCH] pidhash: don't count idle threadsOleg Nesterov
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>
2006-03-28[PATCH] kill SET_LINKS/REMOVE_LINKSOleg Nesterov
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>
2006-03-27[PATCH] lightweight robust futexes updatesIngo Molnar
- 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>
2006-03-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds
* 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/
2006-03-26[PATCH] hrtimers: remove data fieldRoman Zippel
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>
2006-03-26BUG_ON() Conversion in kernel/fork.cEric Sesterhenn
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>
2006-03-24[PATCH] cpuset memory spread slab cache optimizationsPaul Jackson
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>
2006-03-23[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23Jens Axboe
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-03-23[PATCH] Shrinks sizeof(files_struct) and better layoutEric Dumazet
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>
2006-03-22[PATCH] unshare: Error if passed unsupported flagsEric W. Biederman
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>
2006-03-18[PATCH] disable unshare(CLONE_VM) for nowOleg Nesterov
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>
2006-03-17[PATCH] unshare: Use rcu_assign_pointer when setting sighandEric W. Biederman
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>
2006-03-14[PATCH] Fix sigaltstack corruption among cloned threadsGOTO Masanori
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>
2006-03-11[PATCH] remove __put_task_struct_cb export againChristoph Hellwig
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>
2006-02-15[PATCH] fix kill_proc_info() vs fork() theoretical raceOleg Nesterov
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>
2006-02-15[PATCH] fix kill_proc_info() vs CLONE_THREAD raceOleg Nesterov
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>
2006-02-07[PATCH] unshare system call -v5: unshare filesJANAK DESAI
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>
2006-02-07[PATCH] unshare system call -v5: unshare vmJANAK DESAI
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>
2006-02-07[PATCH] unshare system call -v5: unshare namespaceJANAK DESAI
If the namespace 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>
2006-02-07[PATCH] unshare system call -v5: unshare filesystem infoJANAK DESAI
If filesystem 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>
2006-02-07[PATCH] unshare system call -v5: system call handler functionJANAK DESAI
sys_unshare system call handler function accepts the same flags as clone system call, checks constraints on each of the flags and invokes corresponding unshare functions to disassociate respective process context if it was being shared with another task. Here is the link to a program for testing unshare system call. http://prdownloads.sourceforge.net/audit/unshare_test.c?download Please note that because of a problem in rmdir associated with bind mounts and clone with CLONE_NEWNS, the test fails while trying to remove temporary test directory. You can remove that temporary directory by doing rmdir, twice, from the command line. The first will fail with EBUSY, but the second will succeed. I have reported the problem to Ram Pai and Al Viro with a small program which reproduces the problem. Al told us yesterday that he will be looking at the problem soon. I have tried multiple rmdirs from the unshare_test program itself, but for some reason that is not working. Doing two rmdirs from command line does seem to remove the directory. 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>
2006-02-01[PATCH] hrtimers: cleanups and simplificationsGeorge Anzinger
Clean up the interface to hrtimers by changing the init code to pass the mode as well as the clock. This allow the init code to select the correct base and eliminates extra timer re-init code in posix-timers. We also simplify the restart interface nanosleep use. Signed-off-by: George Anzinger <george@mvista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11[PATCH] x86_64: Inclusion of ScaleMP vSMP architecture patches - vsmp_alignRavikiran G Thirumalai
vSMP specific alignment patch to 1. Define INTERNODE_CACHE_SHIFT for vSMP 2. Use this for alignment of critical structures 3. Use INTERNODE_CACHE_SHIFT for ARCH_MIN_TASKALIGN, and let the slab align task_struct allocations to the internode cacheline size 4. Introduce and use ARCH_MIN_MMSTRUCT_ALIGN for mm_struct slab allocations. Signed-off-by: Ravikiran Thirumalai <kiran@scalemp.com> Signed-off-by: Shai Fultheim <shai@scalemp.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11[PATCH] move capable() to capability.hRandy.Dunlap
- Move capable() from sched.h to capability.h; - Use <linux/capability.h> where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: switch itimers to hrtimerThomas Gleixner
switch itimers to a hrtimers-based implementation Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09[PATCH] mutex subsystem, debugging codeIngo Molnar
mutex implementation - add debugging code. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org>
2006-01-08[PATCH] copy_process: error path cleanupOleg Nesterov
This patch moves 'fork_out:' under 'bad_fork_free:', and removes now unneeded 'if (retval)' check. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] fork: fix race in setting child's pgrp and ttyOren Laadan
In fork, child should recopy parent's pgrp/tty after it has tasklist_lock. Otherwise following a setpgid() on the parent, *after* copy_signal(), the child will own a stale pgrp (which may be reused); (eg. if copy_mm() sleeps a long while due to memory pressure). Similar issue for the tty. Signed-off-by: Oren Laadan <orenl@cs.columbia.edu> Cc: 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>
2006-01-08[PATCH] cpuset: fork hook fixPaul Jackson
Fix obscure, never seen in real life, cpuset fork race. The cpuset_fork() call in fork.c was setting up the correct task->cpuset pointer after the tasklist_lock was dropped, which briefly exposed the newly forked process with an unsafe (copied from parent without locks or usage counter increment) cpuset pointer. In theory, that exposed cpuset pointer could have been pointing at a cpuset that was already freed and removed, and in theory another task that had been sitting on the tasklist_lock waiting to scan the task list could have raced down the entire tasklist, found our new child at the far end, and dereferenced that bogus cpuset pointer. To fix, setup up the correct cpuset pointer in the new child by calling cpuset_fork() before the new task is linked into the tasklist, and with that, add a fork failure case, to dereference that cpuset, if the fork fails along the way, after cpuset_fork() was called. Had to remove a BUG_ON() from cpuset_exit(), because it was no longer valid - the call to cpuset_exit() from a failed fork would not have PF_EXITING set. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] RCU signal handlingIngo Molnar
RCU tasklist_lock and RCU signal handling: send signals RCU-read-locked instead of tasklist_lock read-locked. This is a scalability improvement on SMP and a preemption-latency improvement under PREEMPT_RCU. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: William Irwin <wli@holomorphy.com> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-28[PATCH] cpuset fork locking fixPaul Jackson
Move the cpuset_fork() call below the write_unlock_irq call in kernel/fork.c copy_process(). Since the cpuset-dual-semaphore-locking-overhaul.patch, the cpuset_fork() routine acquires task_lock(), so cannot be called while holding the tasklist_lock for write. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-28[PATCH] fork.c: proc_fork_connector() called under write_lock()Andrew Morton
Don't do that - it does GFP_KERNEL allocations, for a start. (Reported by Guillaume Thouvenin <guillaume.thouvenin@bull.net>) Acked-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-22[PATCH] unpaged: copy_page_range vmaHugh Dickins
For copy_one_pte's print_bad_pte to show the task correctly (instead of "???"), dup_mmap must pass down parent vma rather than child vma. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13[PATCH] aio: remove kioctx from mm_structZach Brown
Sync iocbs have a life cycle that don't need a kioctx. Their retrying, if any, is done in the context of their owner who has allocated them on the stack. The sole user of a sync iocb's ctx reference was aio_complete() checking for an elevated iocb ref count that could never happen. No path which grabs an iocb ref has access to sync iocbs. If we were to implement sync iocb cancelation it would be done by the owner of the iocb using its on-stack reference. Removing this chunk from aio_complete allows us to remove the entire kioctx instance from mm_struct, reducing its size by a third. On a i386 testing box the slab size went from 768 to 504 bytes and from 5 to 8 per page. Signed-off-by: Zach Brown <zach.brown@oracle.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13[PATCH] m68k: introduce setup_thread_stack() and end_of_stack()Al Viro
encapsulates the rest of arch-dependent operations with thread_info access. Two new helpers - setup_thread_stack() and end_of_stack(). For normal case the former consists of copying thread_info of parent to new thread_info and the latter returns pointer immediately past the end of thread_info. Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13[PATCH] m68k: introduce task_thread_infoAl Viro
new helper - task_thread_info(task). On platforms that have thread_info allocated separately (i.e. in default case) it simply returns task->thread_info. m68k wants (and for good reasons) to embed its thread_info into task_struct. So it will (in later patch) have task_thread_info() of its own. For now we just add a macro for generic case and convert existing instances of its body in core kernel to uses of new macro. Obviously safe - all normal architectures get the same preprocessor output they used to get. Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[SPARC64] mm: context switch ptlockHugh Dickins
sparc64 is unique among architectures in taking the page_table_lock in its context switch (well, cris does too, but erroneously, and it's not yet SMP anyway). This seems to be a private affair between switch_mm and activate_mm, using page_table_lock as a per-mm lock, without any relation to its uses elsewhere. That's fine, but comment it as such; and unlock sooner in switch_mm, more like in activate_mm (preemption is disabled here). There is a block of "if (0)"ed code in smp_flush_tlb_pending which would have liked to rely on the page_table_lock, in switch_mm and elsewhere; but its comment explains how dup_mmap's flush_tlb_mm defeated it. And though that could have been changed at any time over the past few years, now the chance vanishes as we push the page_table_lock downwards, and perhaps split it per page table page. Just delete that block of code. Which leaves the mysterious spin_unlock_wait(&oldmm->page_table_lock) in kernel/fork.c copy_mm. Textual analysis (supported by Nick Piggin) suggests that the comment was written by DaveM, and that it relates to the defeated approach in the sparc64 smp_flush_tlb_pending. Just delete this block too. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: David S. Miller <davem@davemloft.net>