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  1. 04 9月, 2009 5 次提交
  3. 02 9月, 2009 2 次提交
  5. 29 8月, 2009 1 次提交
  7. 28 8月, 2009 3 次提交
  9. 27 8月, 2009 1 次提交
    • O
      clone(): fix race between copy_process() and de_thread() · 4ab6c083
      由 Oleg Nesterov 提交于 
      Spotted by Hiroshi Shimamoto who also provided the test-case below.

copy_process() uses signal->count as a reference counter, but it is not.
This test case

	#include <sys/types.h>
	#include <sys/wait.h>
	#include <unistd.h>
	#include <stdio.h>
	#include <errno.h>
	#include <pthread.h>

	void *null_thread(void *p)
	{
		for (;;)
			sleep(1);

		return NULL;
	}

	void *exec_thread(void *p)
	{
		execl("/bin/true", "/bin/true", NULL);

		return null_thread(p);
	}

	int main(int argc, char **argv)
	{
		for (;;) {
			pid_t pid;
			int ret, status;

			pid = fork();
			if (pid < 0)
				break;

			if (!pid) {
				pthread_t tid;

				pthread_create(&tid, NULL, exec_thread, NULL);
				for (;;)
					pthread_create(&tid, NULL, null_thread, NULL);
			}

			do {
				ret = waitpid(pid, &status, 0);
			} while (ret == -1 && errno == EINTR);
		}

		return 0;
	}

quickly creates an unkillable task.

If copy_process(CLONE_THREAD) races with de_thread()
copy_signal()->atomic(signal->count) breaks the signal->notify_count
logic, and the execing thread can hang forever in kernel space.

Change copy_process() to increment count/live only when we know for sure
we can't fail.  In this case the forked thread will take care of its
reference to signal correctly.

If copy_process() fails, check CLONE_THREAD flag.  If it it set - do
nothing, the counters were not changed and current belongs to the same
thread group.  If it is not set, ->signal must be released in any case
(and ->count must be == 1), the forked child is the only thread in the
thread group.

We need more cleanups here, in particular signal->count should not be used
by de_thread/__exit_signal at all.  This patch only fixes the bug.
Reported-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Tested-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NRoland McGrath <roland@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4ab6c083
  11. 22 8月, 2009 1 次提交
    • P
      perf_counter: Fix typo in read() output generation · 4464fcaa
      由 Peter Zijlstra 提交于 
      When you iterate a list, using the iterator is useful.

Before:

   ID: 5
   ID: 5
   ID: 5
   ID: 5
   EVNT: 0x40088b scale: nan ID: 5 CNT: 1006252 ID: 6 CNT: 1011090 ID: 7 CNT: 1011196 ID: 8 CNT: 1011095
   EVNT: 0x40088c scale: 1.000000 ID: 5 CNT: 2003065 ID: 6 CNT: 2011671 ID: 7 CNT: 2012620 ID: 8 CNT: 2013479
   EVNT: 0x40088c scale: 1.000000 ID: 5 CNT: 3002390 ID: 6 CNT: 3015996 ID: 7 CNT: 3018019 ID: 8 CNT: 3020006
   EVNT: 0x40088b scale: 1.000000 ID: 5 CNT: 4002406 ID: 6 CNT: 4021120 ID: 7 CNT: 4024241 ID: 8 CNT: 4027059

After:

   ID: 1
   ID: 2
   ID: 3
   ID: 4
   EVNT: 0x400889 scale: nan ID: 1 CNT: 1005270 ID: 2 CNT: 1009833 ID: 3 CNT: 1010065 ID: 4 CNT: 1010088
   EVNT: 0x400898 scale: nan ID: 1 CNT: 2001531 ID: 2 CNT: 2022309 ID: 3 CNT: 2022470 ID: 4 CNT: 2022627
   EVNT: 0x400888 scale: 0.489467 ID: 1 CNT: 3001261 ID: 2 CNT: 3027088 ID: 3 CNT: 3027941 ID: 4 CNT: 3028762
Reported-by: Nstephane eranian <eranian@googlemail.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey J Ashford <cjashfor@us.ibm.com>
Cc: perfmon2-devel <perfmon2-devel@lists.sourceforge.net>
LKML-Reference: <1250867976.7538.73.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4464fcaa
  13. 21 8月, 2009 1 次提交
  15. 20 8月, 2009 2 次提交
    • H
      sched: Use for_each_class macro in move_one_task() · cde7e5ca
      由 Hiroshi Shimamoto 提交于 
      Replace for loop with the macro for_each_class to cleanup.
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
LKML-Reference: <4A8A277D.4090304@ct.jp.nec.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      cde7e5ca
    • S
      clockevent: Prevent dead lock on clockevents_lock · f833bab8
      由 Suresh Siddha 提交于 
      Currently clockevents_notify() is called with interrupts enabled at
some places and interrupts disabled at some other places.

This results in a deadlock in this scenario.

cpu A holds clockevents_lock in clockevents_notify() with irqs enabled
cpu B waits for clockevents_lock in clockevents_notify() with irqs disabled
cpu C doing set_mtrr() which will try to rendezvous of all the cpus.

This will result in C and A come to the rendezvous point and waiting
for B. B is stuck forever waiting for the spinlock and thus not
reaching the rendezvous point.

Fix the clockevents code so that clockevents_lock is taken with
interrupts disabled and thus avoid the above deadlock.

Also call lapic_timer_propagate_broadcast() on the destination cpu so
that we avoid calling smp_call_function() in the clockevents notifier
chain.

This issue left us wondering if we need to change the MTRR rendezvous
logic to use stop machine logic (instead of smp_call_function) or add
a check in spinlock debug code to see if there are other spinlocks
which gets taken under both interrupts enabled/disabled conditions.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: "Brown Len" <len.brown@intel.com>
LKML-Reference: <1250544899.2709.210.camel@sbs-t61.sc.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      f833bab8
  17. 19 8月, 2009 14 次提交
  19. 18 8月, 2009 3 次提交
    • T
      genirq: Wake up irq thread after action has been installed · 69ab8494
      由 Thomas Gleixner 提交于 
      The wake_up_process() of the new irq thread in __setup_irq() is too
early as the irqaction is not yet fully initialized especially
action->irq is not yet set. The interrupt thread might dereference the
wrong irq descriptor.

Move the wakeup after the action is installed and action->irq has been
set.
Reported-by: NMichael Buesch <mb@bu3sch.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NMichael Buesch <mb@bu3sch.de>
      69ab8494
    • I
      perf_counter: Fix the PARISC build · f738eb1b
      由 Ingo Molnar 提交于 
      PARISC does not build:

/home/mingo/tip/kernel/perf_counter.c: In function 'perf_counter_index':
/home/mingo/tip/kernel/perf_counter.c:2016: error: 'PERF_COUNTER_INDEX_OFFSET' undeclared (first use in this function)
/home/mingo/tip/kernel/perf_counter.c:2016: error: (Each undeclared identifier is reported only once
/home/mingo/tip/kernel/perf_counter.c:2016: error: for each function it appears in.)

As PERF_COUNTER_INDEX_OFFSET is not defined.

Now, we could define it in the architecture - but lets also provide
a core default of 0 (which happens to be what all but one
architecture uses at the moment).

Architectures that need a different index offset should set this
value in their asm/perf_counter.h files.

Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f738eb1b
    • Z
      ftrace: Unify effect of writing to trace_options and option/* · f2d84b65
      由 Zhaolei 提交于 
      "echo noglobal-clock > trace_options" can be used to change trace
clock but "echo 0 > options/global-clock" can't. The flag toggling
will be silently accepted without actually changing the clock callback.

We can fix it by using set_tracer_flags() in
trace_options_core_write().

Changelog:
v1->v2: Simplified switch() after Li Zefan <lizf@cn.fujitsu.com>'s
        suggestion
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      f2d84b65
  21. 17 8月, 2009 3 次提交
    • A
      timers: Drop write permission on /proc/timer_list · de809347
      由 Amerigo Wang 提交于 
      /proc/timer_list and /proc/slabinfo are not supposed to be
written, so there should be no write permissions on it.
Signed-off-by: NWANG Cong <amwang@redhat.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: linux-mm@kvack.org
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Amerigo Wang <amwang@redhat.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20090817094525.6355.88682.sendpatchset@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      de809347
    • P
      perf_counter: Check task on counter read IPI · e1ac3614
      由 Paul Mackerras 提交于 
      In general, code in perf_counter.c that is called through an
IPI checks, for per-task counters, that the counter's task is
still the current task.  This is to handle the race condition
where the cpu switches from the task we want to another task in
the interval between sending the IPI and the IPI arriving and
being handled on the target CPU.

For some reason, __perf_counter_read is missing this check, yet
there is no reason why the race condition can't occur.  This
adds a check that the current task is the one we want.  If it
isn't, we just return.  In that case the counter->count value
should be up to date, since it will have been updated when the
counter was scheduled out, which must have happened since the
IPI was sent.

I don't have an example of an actual failure due to this race,
but it seems obvious that it could occur and we need to guard
against it.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <19076.63614.277861.368125@drongo.ozlabs.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e1ac3614
    • E
      Security/SELinux: seperate lsm specific mmap_min_addr · 788084ab
      由 Eric Paris 提交于 
      Currently SELinux enforcement of controls on the ability to map low memory
is determined by the mmap_min_addr tunable.  This patch causes SELinux to
ignore the tunable and instead use a seperate Kconfig option specific to how
much space the LSM should protect.

The tunable will now only control the need for CAP_SYS_RAWIO and SELinux
permissions will always protect the amount of low memory designated by
CONFIG_LSM_MMAP_MIN_ADDR.

This allows users who need to disable the mmap_min_addr controls (usual reason
being they run WINE as a non-root user) to do so and still have SELinux
controls preventing confined domains (like a web server) from being able to
map some area of low memory.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>
      788084ab
  23. 14 8月, 2009 1 次提交
    • L
      genirq: prevent wakeup of freed irq thread · 2d860ad7
      由 Linus Torvalds 提交于 
      free_irq() can remove an irqaction while the corresponding interrupt
is in progress, but free_irq() sets action->thread to NULL
unconditionally, which might lead to a NULL pointer dereference in
handle_IRQ_event() when the hard interrupt context tries to wake up
the handler thread.

Prevent this by moving the thread stop after synchronize_irq(). No
need to set action->thread to NULL either as action is going to be
freed anyway.

This fixes a boot crash reported against preempt-rt which uses the
mainline irq threads code to implement full irq threading.

[ tglx: removed local irqthread variable ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      2d860ad7
  25. 13 8月, 2009 3 次提交
    • P
      perf_counter: Report the cloning task as parent on perf_counter_fork() · 94d5d1b2
      由 Peter Zijlstra 提交于 
      A bug in (9f498cc5: perf_counter: Full task tracing) makes
profiling multi-threaded apps it go belly up.

[ output as: (PID:TID):(PPID:PTID) ]

 # ./perf report -D | grep FORK
0x4b0 [0x18]: PERF_EVENT_FORK: (3237:3237):(3236:3236)
0xa10 [0x18]: PERF_EVENT_FORK: (3237:3238):(3236:3236)
0xa70 [0x18]: PERF_EVENT_FORK: (3237:3239):(3236:3236)
0xad0 [0x18]: PERF_EVENT_FORK: (3237:3240):(3236:3236)
0xb18 [0x18]: PERF_EVENT_FORK: (3237:3241):(3236:3236)

Shows us that the test (27d028de perf report: Update for the new
FORK/EXIT events) in builtin-report.c:

        /*
         * A thread clone will have the same PID for both
         * parent and child.
         */
        if (thread == parent)
                return 0;

Will clearly fail.

The problem is that perf_counter_fork() reports the actual
parent, instead of the cloning thread.

Fixing that (with the below patch), yields:

 # ./perf report -D | grep FORK
0x4c8 [0x18]: PERF_EVENT_FORK: (1590:1590):(1589:1589)
0xbd8 [0x18]: PERF_EVENT_FORK: (1590:1591):(1590:1590)
0xc80 [0x18]: PERF_EVENT_FORK: (1590:1592):(1590:1590)
0x3338 [0x18]: PERF_EVENT_FORK: (1590:1593):(1590:1590)
0x66b0 [0x18]: PERF_EVENT_FORK: (1590:1594):(1590:1590)

Which both makes more sense and doesn't confuse perf report
anymore.
Reported-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: paulus@samba.org
Cc: Anton Blanchard <anton@samba.org>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <1250172882.5241.62.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      94d5d1b2
    • P
      perf_counter: Fix an ipi-deadlock · 970892a9
      由 Peter Zijlstra 提交于 
      perf_pending_counter() is called from IRQ context and will call
perf_counter_disable(), however perf_counter_disable() uses
smp_call_function_single() which doesn't fancy being used with
IRQs disabled due to IPI deadlocks.

Fix this by making it use the local __perf_counter_disable()
call and teaching the counter_sched_out() code about pending
disables as well.

This should cover the case where a counter migrates before the
pending queue gets processed.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey J Ashford <cjashfor@us.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
LKML-Reference: <20090813103655.244097721@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      970892a9
    • P
      perf: Rework/fix the whole read vs group stuff · 3dab77fb
      由 Peter Zijlstra 提交于 
      Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce
PERF_FORMAT_GROUP to deal with group reads in a more generic
way.

This allows you to get group reads out of read() as well.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey J Ashford <cjashfor@us.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
LKML-Reference: <20090813103655.117411814@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3dab77fb