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2008-04-30handle_stop_signal: unify partial/full stop handlingOleg Nesterov
Now that handle_stop_signal() doesn't drop ->siglock, we can't see both ->group_stop_count && SIGNAL_STOP_STOPPED. Merge two "if" branches. As Roland pointed out, we never actually needed 2 do_notify_parent_cldstop() calls. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30kill_pid_info: don't take now unneeded tasklist_lockOleg Nesterov
Previously handle_stop_signal(SIGCONT) could drop ->siglock. That is why kill_pid_info(SIGCONT) takes tasklist_lock to make sure the target task can't go away after unlock. Not needed now. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: re-assign CLD_CONTINUED notification from the sender to recieverOleg Nesterov
Based on discussion with Jiri and Roland. In short: currently handle_stop_signal(SIGCONT, p) sends the notification to p->parent, with this patch p itself notifies its parent when it becomes running. handle_stop_signal(SIGCONT) has to drop ->siglock temporary in order to notify the parent with do_notify_parent_cldstop(). This leads to multiple problems: - as Jiri Kosina pointed out, the stopped task can resume without actually seeing SIGCONT which may have a handler. - we race with another sig_kernel_stop() signal which may come in that window. - we race with sig_fatal() signals which may set SIGNAL_GROUP_EXIT in that window. - we can't avoid taking tasklist_lock() while sending SIGCONT. With this patch handle_stop_signal() just sets the new SIGNAL_CLD_CONTINUED flag in p->signal->flags and returns. The notification is sent by the first task which returns from finish_stop() (there should be at least one) or any other signalled thread from get_signal_to_deliver(). This is a user-visible change. Say, currently kill(SIGCONT, stopped_child) can't return without seeing SIGCHLD, with this patch SIGCHLD can be delayed unpredictably. Another difference is that if the child is ptraced by another process, CLD_CONTINUED may be delivered to ->real_parent after ptrace_detach() while currently it always goes to the tracer which doesn't actually need this notification. Hopefully not a problem. The patch asks for the futher obvious cleanups, I'll send them separately. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: cleanup security_task_kill() usage/implementationOleg Nesterov
Every implementation of ->task_kill() does nothing when the signal comes from the kernel. This is correct, but means that check_kill_permission() should call security_task_kill() only for SI_FROMUSER() case, and we can remove the same check from ->task_kill() implementations. (sadly, check_kill_permission() is the last user of signal->session/__session but we can't s/task_session_nr/task_session/ here). NOTE: Eric W. Biederman pointed out cap_task_kill() should die, and I think he is very right. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: David Quigley <dpquigl@tycho.nsa.gov> Cc: Eric Paris <eparis@redhat.com> Cc: Harald Welte <laforge@gnumonks.org> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: consolidate send_sigqueue and send_group_sigqueuePavel Emelyanov
Both functions do the same thing after proper locking, but with different sigpending structs, so move the common code into a helper. After this we have 4 places that look very similar: send_sigqueue: calls do_send_sigqueue and signal_wakeup send_group_sigqueue: calls do_send_sigqueue and __group_complete_signal __group_send_sig_info: calls send_signal and __group_complete_signal specific_send_sig_info: calls send_signal and signal_wakeup Besides, send_signal performs actions similar to do_send_sigqueue's and __group_complete_signal - to signal_wakeup. It looks like they can be consolidated gracefully. Oleg said: Personally, I think this change is very good. But send_sigqueue() and send_group_sigqueue() have a very subtle difference which I was never able to understand. Let's suppose that sigqueue is already queued, and the signal is ignored (the latter means we should re-schedule cpu timer or handle overrruns). In that case send_sigqueue() returns 0, but send_group_sigqueue() returns 1. I think this is not the problem (in fact, I think this patch makes the behaviour more correct), but I hope Thomas can take a look and confirm. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: clean dequeue_signal from excess checks and assignmentsPavel Emelyanov
The signr variable may be declared without initialization - it is set ro the return value from __dequeue_signal() right at the function beginning. Besides, after recalc_sigpending() two checks for signr to be not 0 may be merged into one. Both if-s become easier to read. Thanks to Oleg for pointing out mistakes in the first version of this patch. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: consolidate checks for whether or not to ignore a signalPavel Emelyanov
Both sig_ignored() and do_sigaction() check for signr to be explicitly or implicitly ignored. Introduce a helper for them. This patch is aimed to help handling signals by pid namespace's init, and was derived from one of Oleg's patches https://lists.linux-foundation.org/pipermail/containers/2007-December/009308.html so, if he doesn't mind, he should be considered as an author. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30lock_task_sighand: add rcu lock/unlockOleg Nesterov
Most of the callers of lock_task_sighand() doesn't actually need rcu_lock(). lock_task_sighand() needs it only to safely play with tsk->sighand, it can take the lock itself. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: do_signal_stop(): use signal_group_exit()Oleg Nesterov
do_signal_stop() needs signal_group_exit() but checks sig->group_exit_task. This (optimization) is correct, SIGNAL_STOP_DEQUEUED and SIGNAL_GROUP_EXIT are mutually exclusive, but looks confusing. Use signal_group_exit(), this is not fastpath, the code clarity is more important. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: consolidate checking for ignored/legacy signalsPavel Emelyanov
Two callers for send_signal() - the specific_send_sig_info and the __group_send_sig_info - both check for sig to be ignored or already queued. Move these checks into send_signal() and make it return 1 to indicate that the signal is dropped, but there's no error in this. Besides, merge comments and spell-check them. [oleg@tv-sign.ru: simplifications] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: turn LEGACY_QUEUE macro into static inline functionPavel Emelyanov
This makes the code more readable, due to less brackets and small letters in name. I also move it above the send_signal() as a preparation for the 3rd patch. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30signals: remove unused variable from send_signal()Pavel Emelyanov
This function doesn't change the ret's value and thus always returns 0, with a single exception of returning -EAGAIN explicitly. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-21trivial: small cleanupsPavel Machek
These are small cleanups all over the tree. Trivial style and comment changes to fs/select.c, kernel/signal.c, kernel/stop_machine.c & mm/pdflush.c Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
2008-04-18ptrace_signal subroutineRoland McGrath
This breaks out the ptrace handling from get_signal_to_deliver into a new subroutine. The actual code there doesn't change, and it gets inlined into nearly identical compiled code. This makes the function substantially shorter and thus easier to read, and it nicely isolates the ptrace magic. Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-04freezer vs stopped or tracedRoland McGrath
This changes the "freezer" code used by suspend/hibernate in its treatment of tasks in TASK_STOPPED (job control stop) and TASK_TRACED (ptrace) states. As I understand it, the intent of the "freezer" is to hold all tasks from doing anything significant. For this purpose, TASK_STOPPED and TASK_TRACED are "frozen enough". It's possible the tasks might resume from ptrace calls (if the tracer were unfrozen) or from signals (including ones that could come via timer interrupts, etc). But this doesn't matter as long as they quickly block again while "freezing" is in effect. Some minor adjustments to the signal.c code make sure that try_to_freeze() very shortly follows all wakeups from both kinds of stop. This lets the freezer code safely leave stopped tasks unmolested. Changing this fixes the longstanding bug of seeing after resuming from suspend/hibernate your shell report "[1] Stopped" and the like for all your jobs stopped by ^Z et al, as if you had freshly fg'd and ^Z'd them. It also removes from the freezer the arcane special case treatment for ptrace'd tasks, which relied on intimate knowledge of ptrace internals. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-13remove final fastcall usersHarvey Harrison
fastcall always expands to empty, remove it. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08Get rid of the kill_pgrp_info() functionPavel Emelyanov
There's only one caller left - the kill_pgrp one - so merge these two functions and forget the kill_pgrp_info one. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Reviewed-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08Clean up the kill_something_infoPavel Emelyanov
This is the first step (of two) in removing the kill_pgrp_info. All the users of this function are in kernel/signal.c, but all they need is to call __kill_pgrp_info() with the tasklist_lock read-locked. Fortunately, one of its users is the kill_something_info(), which already needs this lock in one of its branches, so clean these branches up and call the __kill_pgrp_info() directly. Based on Oleg's view of how this function should look. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08ITIMER_REAL: convert to use struct pidOleg Nesterov
signal_struct->tsk points to the ->group_leader and thus we have the nasty code in de_thread() which has to change it and restart ->real_timer if the leader is changed. Use "struct pid *leader_pid" instead. This also allows us to kill now unneeded send_group_sig_info(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Pavel Emelyanov <xemul@openvz.org> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08uglify kill_pid_info() to fix kill() vs exec() raceOleg Nesterov
kill_pid_info()->pid_task() could be the old leader of the execing process. In that case it is possible that the leader will be released before we take siglock. This means that kill_pid_info() (and thus sys_kill()) can return a false -ESRCH. Change the code to retry when lock_task_sighand() fails. The endless loop is not possible, __exit_signal() both clears ->sighand and does detach_pid(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08move the related code from exit_notify() to exit_signals()Oleg Nesterov
The previous bugfix was not optimal, we shouldn't care about group stop when we are the only thread or the group stop is in progress. In that case nothing special is needed, just set PF_EXITING and return. Also, take the related "TIF_SIGPENDING re-targeting" code from exit_notify(). So, from the performance POV the only difference is that we don't trust !signal_pending() until we take ->siglock. But this in fact fixes another ___pure___ theoretical minor race. __group_complete_signal() finds the task without PF_EXITING and chooses it as the target for signal_wake_up(). But nothing prevents this task from exiting in between without noticing the pending signal and thus unpredictably delaying the actual delivery. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08fix group stop with exit raceOleg Nesterov
do_signal_stop() counts all sub-thread and sets ->group_stop_count accordingly. Every thread should decrement ->group_stop_count and stop, the last one should notify the parent. However a sub-thread can exit before it notices the signal_pending(), or it may be somewhere in do_exit() already. In that case the group stop never finishes properly. Note: this is a minimal fix, we can add some optimizations later. Say we can return quickly if thread_group_empty(). Also, we can move some signal related code from exit_notify() to exit_signals(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08ptrace_stop: fix racy nonstop_code settingOleg Nesterov
If the tracer is gone and we are not going to stop, ptrace_stop() sets ->exit_code = nostop_code. However, the tracer could actually clear the exit code before detaching. In that case get_signal_to_deliver() "resends" the signal which was cancelled by the debugger. For example, it is possible that a quick PTRACE_ATTACH + PTRACE_DETACH can leave the tracee in STOPPED state. Change the behaviour of ptrace_stop(). If the caller is ptrace notify(), we should always clear ->exit_code. If the caller is get_signal_to_deliver(), we should not touch it at all. To do so, change the nonstop_code parameter to "bool clear_code" and change the callers accordingly. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08ptrace_stop: fix the race with ptrace detach+attachOleg Nesterov
If the tracer went away (may_ptrace_stop() failed), ptrace_stop() drops tasklist and then changes the ->state from TASK_TRACED to TASK_RUNNING. This can fool another tracer which attaches to us in between. Change the ->state under tasklist_lock to ensure that ptrace_check_attach() can't wrongly succeed. Also, remove the unnecessary mb(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08kill PT_ATTACHEDOleg Nesterov
Since the patch "Fix ptrace_attach()/ptrace_traceme()/de_thread() race" commit f5b40e363ad6041a96e3da32281d8faa191597b9 we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock. This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer" which were needed to catch the "ptrace attach is in progress" case. We can also remove the flag itself since nobody else uses it. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06Add arch_ptrace_stopRoland McGrath
This adds support to allow asm/ptrace.h to define two new macros, arch_ptrace_stop_needed and arch_ptrace_stop. These control special machine-specific actions to be done before a ptrace stop. The new code compiles away to nothing when the new macros are not defined. This is the case on all machines to begin with. On ia64, these macros will be defined to solve the long-standing issue of ptrace vs register backing store. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Petr Tesarik <ptesarik@suse.cz> Cc: Tony Luck <tony.luck@intel.com> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06use __set_task_state() for TRACED/STOPPED tasksOleg Nesterov
1. It is much easier to grep for ->state change if __set_task_state() is used instead of the direct assignment. 2. ptrace_stop() and handle_group_stop() use set_task_state() which adds the unneeded mb() (btw even if we use mb() it is still possible that do_wait() sees the new ->state but not ->exit_code, but this is ok). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05exec: rework the group exit and fix the race with killOleg Nesterov
As Roland pointed out, we have the very old problem with exec. de_thread() sets SIGNAL_GROUP_EXIT, kills other threads, changes ->group_leader and then clears signal->flags. All signals (even fatal ones) sent in this window (which is not too small) will be lost. With this patch exec doesn't abuse SIGNAL_GROUP_EXIT. signal_group_exit(), the new helper, should be used to detect exit_group() or exec() in progress. It can have more users, but this patch does only strictly necessary changes. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robin Holt <holt@sgi.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05remove handle_group_stop() in favor of do_signal_stop()Oleg Nesterov
Every time we set SIGNAL_GROUP_EXIT or clear SIGNAL_STOP_DEQUEUED we also reset ->group_stop_count. This means that the SIGNAL_GROUP_EXIT check in handle_group_stop() is not needed, and do_signal_stop() should check SIGNAL_STOP_DEQUEUED only when ->group_stop_count == 0. With these changes handle_group_stop() becomes the subset of do_signal_stop(), we can kill it and use do_signal_stop() instead. Also, a preparation for the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robin Holt <holt@sgi.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05__group_complete_signal(): fix coredump with group stop raceOleg Nesterov
When __group_complete_signal() sees sig_kernel_coredump() signal, it starts the group stop, but sets ->group_exit_task = t in a hope that "t" will actually dequeue this signal and invoke do_coredump(). However, by the time "t" enters get_signal_to_deliver() it is possible that the signal was blocked/ignored or we have another pending !SIG_KERNEL_COREDUMP_MASK signal which will be dequeued first. This means the task could be stopped but not killed. Remove this code from __group_complete_signal(). Note also this patch removes the bogus signal_wake_up(t, 1). This thread can't be STOPPED/TRACED, note the corresponding check in wants_signal(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robin Holt <holt@sgi.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01Ensure that we export __fatal_signal_pending()Trond Myklebust
It may be used by the modules nfs.ko and sunrpc.ko Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> [ Made it a regular export rather than GPL-only - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01Merge branch 'task_killable' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc * 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: (22 commits) Remove commented-out code copied from NFS NFS: Switch from intr mount option to TASK_KILLABLE Add wait_for_completion_killable Add wait_event_killable Add schedule_timeout_killable Use mutex_lock_killable in vfs_readdir Add mutex_lock_killable Use lock_page_killable Add lock_page_killable Add fatal_signal_pending Add TASK_WAKEKILL exit: Use task_is_* signal: Use task_is_* sched: Use task_contributes_to_load, TASK_ALL and TASK_NORMAL ptrace: Use task_is_* power: Use task_is_* wait: Use TASK_NORMAL proc/base.c: Use task_is_* proc/array.c: Use TASK_REPORT perfmon: Use task_is_* ... Fixed up conflicts in NFS/sunrpc manually..
2008-01-30x86: rename the struct pt_regs members for 32/64-bit consistencyH. Peter Anvin
We have a lot of code which differs only by the naming of specific members of structures that contain registers. In order to enable additional unifications, this patch drops the e- or r- size prefix from the register names in struct pt_regs, and drops the x- prefixes for segment registers on the 32-bit side. This patch also performs the equivalent renames in some additional places that might be candidates for unification in the future. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-12-06Add fatal_signal_pendingMatthew Wilcox
Like signal_pending, but it's only true for signals which are fatal to this process Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-12-06Add TASK_WAKEKILLMatthew Wilcox
Set TASK_WAKEKILL for TASK_STOPPED and TASK_TRACED, add TASK_KILLABLE and use TASK_WAKEKILL in signal_wake_up() Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-12-06signal: Use task_is_*Matthew Wilcox
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-11-12sigwait eats blocked default-ignore signalsRoland McGrath
While a signal is blocked, it must be posted even if its action is SIG_IGN or is SIG_DFL with the default action to ignore. This works right most of the time, but is broken when a sigwait (rt_sigtimedwait) is in progress. This changes the early-discard check to respect real_blocked. ~blocked is the set to check for "should wake up now", but ~(blocked|real_blocked) is the set for "blocked" semantics as defined by POSIX. This fixes bugzilla entry 9347, see http://bugzilla.kernel.org/show_bug.cgi?id=9347 Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-30Freezer: do not allow freezing processes to clear TIF_SIGPENDINGRafael J. Wysocki
Do not allow processes to clear their TIF_SIGPENDING if TIF_FREEZE is set, so that they will not race with the freezer (like mysqld does, for example). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@suspend2.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-29x86 merge fallout: umlAl Viro
Don't undef __i386__/__x86_64__ in uml anymore, make sure that (few) places that required adjusting the ifdefs got those. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Use helpers to obtain task pid in printksPavel Emelyanov
The task_struct->pid member is going to be deprecated, so start using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in the kernel. The first thing to start with is the pid, printed to dmesg - in this case we may safely use task_pid_nr(). Besides, printks produce more (much more) than a half of all the explicit pid usage. [akpm@linux-foundation.org: git-drm went and changed lots of stuff] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Dave Airlie <airlied@linux.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Isolate some explicit usage of task->tgidPavel Emelyanov
With pid namespaces this field is now dangerous to use explicitly, so hide it behind the helpers. Also the pid and pgrp fields o task_struct and signal_struct are to be deprecated. Unfortunately this patch cannot be sent right now as this leads to tons of warnings, so start isolating them, and deprecate later. Actually the p->tgid == pid has to be changed to has_group_leader_pid(), but Oleg pointed out that in case of posix cpu timers this is the same, and thread_group_leader() is more preferable. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Uninline find_task_by_xxx set of functionsPavel Emelyanov
The find_task_by_something is a set of macros are used to find task by pid depending on what kind of pid is proposed - global or virtual one. All of them are wrappers above the most generic one - find_task_by_pid_type_ns() - and just substitute some args for it. It turned out, that dereferencing the current->nsproxy->pid_ns construction and pushing one more argument on the stack inline cause kernel text size to grow. This patch moves all this stuff out-of-line into kernel/pid.c. Together with the next patch it saves a bit less than 400 bytes from the .text section. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19pid namespaces: changes to show virtual ids to userPavel Emelyanov
This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19pid namespaces: allow signalling cgroup-initSukadev Bhattiprolu
Only the global-init process must be special - any other cgroup-init process must be killable to prevent run-away processes in the system. TODO: Ideally we should allow killing the cgroup-init only from parent cgroup and prevent it being killed from within the cgroup. But that is a more complex change and will be addressed by a follow-on patch. For now allow the cgroup-init to be terminated by any process with sufficient privileges. Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19pid namespaces: define is_global_init() and is_container_init()Serge E. Hallyn
is_init() is an ambiguous name for the pid==1 check. Split it into is_global_init() and is_container_init(). A cgroup init has it's tsk->pid == 1. A global init also has it's tsk->pid == 1 and it's active pid namespace is the init_pid_ns. But rather than check the active pid namespace, compare the task structure with 'init_pid_ns.child_reaper', which is initialized during boot to the /sbin/init process and never changes. Changelog: 2.6.22-rc4-mm2-pidns1: - Use 'init_pid_ns.child_reaper' to determine if a given task is the global init (/sbin/init) process. This would improve performance and remove dependence on the task_pid(). 2.6.21-mm2-pidns2: - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc, ppc,avr32}/traps.c for the _exception() call to is_global_init(). This way, we kill only the cgroup if the cgroup's init has a bug rather than force a kernel panic. [akpm@linux-foundation.org: fix comment] [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c] [bunk@stusta.de: kernel/pid.c: remove unused exports] [sukadev@us.ibm.com: Fix capability.c to work with threaded init] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Acked-by: Pavel Emelianov <xemul@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Herbert Poetzel <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19pid namespaces: rename child_reaper() functionSukadev Bhattiprolu
Rename the child_reaper() function to task_child_reaper() to be similar to other task_* functions and to distinguish the function from 'struct pid_namspace.child_reaper'. Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Herbert Poetzel <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19pid namespaces: round up the APIPavel Emelianov
The set of functions process_session, task_session, process_group and task_pgrp is confusing, as the names can be mixed with each other when looking at the code for a long time. The proposals are to * equip the functions that return the integer with _nr suffix to represent that fact, * and to make all functions work with task (not process) by making the common prefix of the same name. For monotony the routines signal_session() and set_signal_session() are replaced with task_session_nr() and set_task_session(), especially since they are only used with the explicit task->signal dereference. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-18freezer: do not send signals to kernel threadsRafael J. Wysocki
The freezer should not send signals to kernel threads, since that may lead to subtle problems. In particular, commit b74d0deb968e1f85942f17080eace015ce3c332c has changed recalc_sigpending_tsk() so that it doesn't clear TIF_SIGPENDING. For this reason, if the freezer continues to send fake signals to kernel threads and the freezing of kernel threads fails, some of them may be running with TIF_SIGPENDING set forever. Accordingly, recalc_sigpending_tsk() shouldn't set the task's TIF_SIGPENDING flag if TIF_FREEZE is set. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17do_sigaction: don't worry about signal_pending()Oleg Nesterov
do_sigaction() returns -ERESTARTNOINTR if signal_pending(). The comment says: * If there might be a fatal signal pending on multiple * threads, make sure we take it before changing the action. I think this is not needed. We should only worry about SIGNAL_GROUP_EXIT case, bit it implies a pending SIGKILL which can't be cleared by do_sigaction. Kill this special case. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17__group_complete_signal: eliminate unneeded wakeup of ->group_exit_taskOleg Nesterov
Cleanup. __group_complete_signal() wakes up ->group_exit_task twice. The second wakeup's state includes TASK_UNINTERRUPTIBLE, which is not very appropriate. Change the code to pass the "correct" argument to signal_wake_up() and kill now unneeded wake_up_process(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>