Commit graph

10217 commits

Author SHA1 Message Date
David S. Miller
053d8f6622 Merge branch 'vhost-net' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost 2010-09-09 21:59:51 -07:00
Linus Torvalds
cd4d4fc413 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: use zalloc_cpumask_var() for gcwq->mayday_mask
  workqueue: fix GCWQ_DISASSOCIATED initialization
  workqueue: Add a workqueue chapter to the tracepoint docbook
  workqueue: fix cwq->nr_active underflow
  workqueue: improve destroy_workqueue() debuggability
  workqueue: mark lock acquisition on worker_maybe_bind_and_lock()
  workqueue: annotate lock context change
  workqueue: free rescuer on destroy_workqueue
2010-09-07 14:08:17 -07:00
Michael S. Tsirkin
73457f0f83 cgroups: fix API thinko
cgroup_attach_task_current_cg API that have upstream is backwards: we
really need an API to attach to the cgroups from another process A to
the current one.

In our case (vhost), a priveledged user wants to attach it's task to cgroups
from a less priveledged one, the API makes us run it in the other
task's context, and this fails.

So let's make the API generic and just pass in 'from' and 'to' tasks.
Add an inline wrapper for cgroup_attach_task_current_cg to avoid
breaking bisect.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
2010-09-05 17:01:37 +03:00
Tejun Heo
9c37547ab6 workqueue: use zalloc_cpumask_var() for gcwq->mayday_mask
alloc_mayday_mask() was using alloc_cpumask_var() making
gcwq->mayday_mask contain garbage after initialization on
CONFIG_CPUMASK_OFFSTACK=y configurations.  This combined with the
previously fixed GCWQ_DISASSOCIATED initialization bug could make
rescuers fall into infinite loop trying to bind to an offline cpu.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: CAI Qian <caiqian@redhat.com>
2010-08-31 11:18:34 +02:00
Tejun Heo
477a3c33d1 workqueue: fix GCWQ_DISASSOCIATED initialization
init_workqueues() incorrectly marks workqueues for all possible CPUs
associated.  Combined with mayday_mask initialization bug, this can
make rescuers keep trying to bind to an offline gcwq indefinitely.
Fix init_workqueues() such that only online CPUs have their gcwqs have
GCWQ_DISASSOCIATED cleared.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: CAI Qian <caiqian@redhat.com>
2010-08-31 10:54:35 +02:00
Linus Torvalds
6f4dbeca1a Merge branch 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM QoS: Fix inline documentation.
  PM QoS: Fix kzalloc() parameters swapped in pm_qos_power_open()
2010-08-28 14:06:19 -07:00
Linus Torvalds
2637d139fb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: pxa27x_keypad - remove input_free_device() in pxa27x_keypad_remove()
  Input: mousedev - fix regression of inverting axes
  Input: uinput - add devname alias to allow module on-demand load
  Input: hil_kbd - fix compile error
  USB: drop tty argument from usb_serial_handle_sysrq_char()
  Input: sysrq - drop tty argument form handle_sysrq()
  Input: sysrq - drop tty argument from sysrq ops handlers
2010-08-28 13:55:31 -07:00
Saravana Kannan
25cc69ec34 PM QoS: Fix inline documentation.
Fix the pm_qos_add_request() kerneldoc comment that doesn't reflect
the behavior of the function after the last PM QoS update.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-08-26 20:18:43 +02:00
Linus Torvalds
d4348c6789 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf, x86, Pentium4: Clear the P4_CCCR_FORCE_OVF flag
  tracing/trace_stack: Fix stack trace on ppc64
2010-08-25 10:50:07 -07:00
Linus Torvalds
5e686019df Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states
  sched: Fix rq->clock synchronization when migrating tasks
2010-08-25 08:40:56 -07:00
Anton Blanchard
151772dbfa tracing/trace_stack: Fix stack trace on ppc64
save_stack_trace() stores the instruction pointer, not the
function descriptor. On ppc64 the trace stack code currently
dereferences the instruction pointer and shows 8 bytes of
instructions in our backtraces:

 # cat /sys/kernel/debug/tracing/stack_trace
        Depth    Size   Location    (26 entries)
        -----    ----   --------
  0)     5424     112   0x6000000048000004
  1)     5312     160   0x60000000ebad01b0
  2)     5152     160   0x2c23000041c20030
  3)     4992     240   0x600000007c781b79
  4)     4752     160   0xe84100284800000c
  5)     4592     192   0x600000002fa30000
  6)     4400     256   0x7f1800347b7407e0
  7)     4144     208   0xe89f0108f87f0070
  8)     3936     272   0xe84100282fa30000

Since we aren't dealing with function descriptors, use %pS
instead of %pF to fix it:

 # cat /sys/kernel/debug/tracing/stack_trace
        Depth    Size   Location    (26 entries)
        -----    ----   --------
  0)     5424     112   ftrace_call+0x4/0x8
  1)     5312     160   .current_io_context+0x28/0x74
  2)     5152     160   .get_io_context+0x48/0xa0
  3)     4992     240   .cfq_set_request+0x94/0x4c4
  4)     4752     160   .elv_set_request+0x60/0x84
  5)     4592     192   .get_request+0x2d4/0x468
  6)     4400     256   .get_request_wait+0x7c/0x258
  7)     4144     208   .__make_request+0x49c/0x610
  8)     3936     272   .generic_make_request+0x390/0x434

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: rostedt@goodmis.org
Cc: fweisbec@gmail.com
LKML-Reference: <20100825013238.GE28360@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-25 13:08:48 +02:00
Tejun Heo
8a2e8e5dec workqueue: fix cwq->nr_active underflow
cwq->nr_active is used to keep track of how many work items are active
for the cpu workqueue, where 'active' is defined as either pending on
global worklist or executing.  This is used to implement the
max_active limit and workqueue freezing.  If a work item is queued
after nr_active has already reached max_active, the work item doesn't
increment nr_active and is put on the delayed queue and gets activated
later as previous active work items retire.

try_to_grab_pending() which is used in the cancellation path
unconditionally decremented nr_active whether the work item being
cancelled is currently active or delayed, so cancelling a delayed work
item makes nr_active underflow.  This breaks max_active enforcement
and triggers BUG_ON() in destroy_workqueue() later on.

This patch fixes this bug by adding a flag WORK_STRUCT_DELAYED, which
is set while a work item in on the delayed list and making
try_to_grab_pending() decrement nr_active iff the work item is
currently active.

The addition of the flag enlarges cwq alignment to 256 bytes which is
getting a bit too large.  It's scheduled to be reduced back to 128
bytes by merging WORK_STRUCT_PENDING and WORK_STRUCT_CWQ in the next
devel cycle.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Johannes Berg <johannes@sipsolutions.net>
2010-08-25 10:33:56 +02:00
Linus Torvalds
502adf5778 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  watchdog: Don't throttle the watchdog
  tracing: Fix timer tracing
2010-08-24 12:21:49 -07:00
Linus Torvalds
3b6c5507a6 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  mutex: Improve the scalability of optimistic spinning
2010-08-24 12:21:02 -07:00
David Alan Gilbert
bac1e74dba PM QoS: Fix kzalloc() parameters swapped in pm_qos_power_open()
sparse spotted that the kzalloc() in pm_qos_power_open() in the
current Linus' git tree had its parameters swapped.  Fix this.

Signed-off-by: David Alan Gilbert <linux@treblig.org>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-08-24 20:22:18 +02:00
Tejun Heo
e41e704bc4 workqueue: improve destroy_workqueue() debuggability
Now that the worklist is global, having works pending after wq
destruction can easily lead to oops and destroy_workqueue() have
several BUG_ON()s to catch these cases.  Unfortunately, BUG_ON()
doesn't tell much about how the work became pending after the final
flush_workqueue().

This patch adds WQ_DYING which is set before the final flush begins.
If a work is requested to be queued on a dying workqueue,
WARN_ON_ONCE() is triggered and the request is ignored.  This clearly
indicates which caller is trying to queue a work on a dying workqueue
and keeps the system working in most cases.

Locking rule comment is updated such that the 'I' rule includes
modifying the field from destruction path.

Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-24 18:01:32 +02:00
Namhyung Kim
972fa1c531 workqueue: mark lock acquisition on worker_maybe_bind_and_lock()
worker_maybe_bind_and_lock() actually grabs gcwq->lock but was missing proper
annotation. Add it. So this patch will remove following sparse warnings:

 kernel/workqueue.c:1214:13: warning: context imbalance in 'worker_maybe_bind_and_lock' - wrong count at exit
 arch/x86/include/asm/irqflags.h:44:9: warning: context imbalance in 'worker_rebind_fn' - unexpected unlock
 kernel/workqueue.c:1991:17: warning: context imbalance in 'rescuer_thread' - unexpected unlock

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-23 11:37:49 +02:00
Namhyung Kim
06bd6ebffa workqueue: annotate lock context change
Some of internal functions called within gcwq->lock context releases and
regrabs the lock but were missing proper annotations. Add it.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-23 11:37:49 +02:00
Tim Chen
9d0f4dcc5c mutex: Improve the scalability of optimistic spinning
There is a scalability issue for current implementation of optimistic
mutex spin in the kernel.  It is found on a 8 node 64 core Nehalem-EX
system (HT mode).

The intention of the optimistic mutex spin is to busy wait and spin on a
mutex if the owner of the mutex is running, in the hope that the mutex
will be released soon and be acquired, without the thread trying to
acquire mutex going to sleep. However, when we have a large number of
threads, contending for the mutex, we could have the mutex grabbed by
other thread, and then another ……, and we will keep spinning, wasting cpu
cycles and adding to the contention.  One possible fix is to quit
spinning and put the current thread on wait-list if mutex lock switch to
a new owner while we spin, indicating heavy contention (see the patch
included).

I did some testing on a 8 socket Nehalem-EX system with a total of 64
cores. Using Ingo's test-mutex program that creates/delete files with 256
threads (http://lkml.org/lkml/2006/1/8/50) , I see the following speed up
after putting in the mutex spin fix:

 ./mutex-test V 256 10
                 Ops/sec
 2.6.34          62864
 With fix        197200

Repeating the test with Aim7 fserver workload, again there is a speed up
with the fix:

                 Jobs/min
 2.6.34          91657
 With fix        149325

To look at the impact on the distribution of mutex acquisition time, I
collected the mutex acquisition time on Aim7 fserver workload with some
instrumentation.  The average acquisition time is reduced by 48% and
number of contentions reduced by 32%.

                 #contentions    Time to acquire mutex (cycles)
 2.6.34          72973           44765791
 With fix        49210           23067129

The histogram of mutex acquisition time is listed below.  The acquisition
time is in 2^bin cycles.  We see that without the fix, the acquisition
time is mostly around 2^26 cycles.  With the fix, we the distribution get
spread out a lot more towards the lower cycles, starting from 2^13.
However, there is an increase of the tail distribution with the fix at
2^28 and 2^29 cycles.  It seems a small price to pay for the reduced
average acquisition time and also getting the cpu to do useful work.

 Mutex acquisition time distribution (acq time = 2^bin cycles):
         2.6.34                  With Fix
 bin     #occurrence     %       #occurrence     %
 11      2               0.00%   120             0.24%
 12      10              0.01%   790             1.61%
 13      14              0.02%   2058            4.18%
 14      86              0.12%   3378            6.86%
 15      393             0.54%   4831            9.82%
 16      710             0.97%   4893            9.94%
 17      815             1.12%   4667            9.48%
 18      790             1.08%   5147            10.46%
 19      580             0.80%   6250            12.70%
 20      429             0.59%   6870            13.96%
 21      311             0.43%   1809            3.68%
 22      255             0.35%   2305            4.68%
 23      317             0.44%   916             1.86%
 24      610             0.84%   233             0.47%
 25      3128            4.29%   95              0.19%
 26      63902           87.69%  122             0.25%
 27      619             0.85%   286             0.58%
 28      0               0.00%   3536            7.19%
 29      0               0.00%   903             1.83%
 30      0               0.00%   0               0.00%

I've done similar experiments with 2.6.35 kernel on smaller boxes as
well.  One is on a dual-socket Westmere box (12 cores total, with HT).
Another experiment is on an old dual-socket Core 2 box (4 cores total, no
HT)

On the 12-core Westmere box, I see a 250% increase for Ingo's mutex-test
program with my mutex patch but no significant difference in aim7's
fserver workload.

On the 4-core Core 2 box, I see the difference with the patch for both
mutex-test and aim7 fserver are negligible.

So far, it seems like the patch has not caused regression on smaller
systems.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org> # .35.x
LKML-Reference: <1282168827.9542.72.camel@schen9-DESK>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-23 10:56:27 +02:00
Peter Zijlstra
c6db67cda7 watchdog: Don't throttle the watchdog
Stephane reported that when the machine locks up, the regular ticks,
which are responsible to resetting the throttle count, stop too.

Hence the NMI watchdog can end up being throttled before it reports on
the locked up state, and we end up being sad..

Cure this by having the watchdog overflow reset its own throttle count.

Reported-by: Stephane Eranian <eranian@google.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1282215916.1926.4696.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-23 10:48:05 +02:00
Arjan van de Ven
e36c886a0f workqueue: Add basic tracepoints to track workqueue execution
With the introduction of the new unified work queue thread pools,
we lost one feature: It's no longer possible to know which worker
is causing the CPU to wake out of idle. The result is that PowerTOP
now reports a lot of "kworker/a:b" instead of more readable results.

This patch adds a pair of tracepoints to the new workqueue code,
similar in style to the timer/hrtimer tracepoints.

With this pair of tracepoints, the next PowerTOP can correctly
report which work item caused the wakeup (and how long it took):

Interrupt (43)            i915      time   3.51ms    wakeups 141
Work      ieee80211_iface_work      time   0.81ms    wakeups  29
Work              do_dbs_timer      time   0.55ms    wakeups  24
Process                   Xorg      time  21.36ms    wakeups   4
Timer    sched_rt_period_timer      time   0.01ms    wakeups   1

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 13:19:37 -07:00
Linus Torvalds
297c5eee37 mm: make the vma list be doubly linked
It's a really simple list, and several of the users want to go backwards
in it to find the previous vma.  So rather than have to look up the
previous entry with 'find_vma_prev()' or something similar, just make it
doubly linked instead.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 08:49:21 -07:00
Dmitry Torokhov
f335397d17 Input: sysrq - drop tty argument form handle_sysrq()
Sysrq operations do not accept tty argument anymore so no need to pass
it to us.

[Stephen Rothwell <sfr@canb.auug.org.au>: fix build breakage in drm code
 caused by sysrq using bool but not including linux/types.h]

[Sachin Sant <sachinp@in.ibm.com>: fix build breakage in s390 keyboadr
 driver]

Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2010-08-21 00:34:45 -07:00
Andrea Righi
b35de43b31 kfifo: implement missing __kfifo_skip_r()
kfifo_skip() is currently broken, due to the missing of the internal
helper function.  Add it.

Signed-off-by: Andrea Righi <arighi@develer.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-20 09:34:54 -07:00
Peter Zijlstra
861d034ee8 sched: Fix rq->clock synchronization when migrating tasks
sched_fork() -- we do task placement in ->task_fork_fair() ensure we
  update_rq_clock() so we work with current time. We leave the vruntime
  in relative state, so the time delay until wake_up_new_task() doesn't
  matter.

wake_up_new_task() -- Since task_fork_fair() left p->vruntime in
  relative state we can safely migrate, the activate_task() on the
  remote rq will call update_rq_clock() and causes the clock to be
  synced (enough).

Tested-by: Jack Daniel <wanders.thirst@gmail.com>
Tested-by: Philby John <pjohn@mvista.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1281002322.1923.1708.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-20 14:59:01 +02:00
Dmitry Torokhov
1495cc9df4 Input: sysrq - drop tty argument from sysrq ops handlers
Noone is using tty argument so let's get rid of it.

Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2010-08-19 22:07:06 -07:00
Linus Torvalds
145c3ae46b Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  fs: brlock vfsmount_lock
  fs: scale files_lock
  lglock: introduce special lglock and brlock spin locks
  tty: fix fu_list abuse
  fs: cleanup files_lock locking
  fs: remove extra lookup in __lookup_hash
  fs: fs_struct rwlock to spinlock
  apparmor: use task path helpers
  fs: dentry allocation consolidation
  fs: fix do_lookup false negative
  mbcache: Limit the maximum number of cache entries
  hostfs ->follow_link() braino
  hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy
  remove SWRITE* I/O types
  kill BH_Ordered flag
  vfs: update ctime when changing the file's permission by setfacl
  cramfs: only unlock new inodes
  fix reiserfs_evict_inode end_writeback second call
2010-08-18 09:35:08 -07:00
Linus Torvalds
1ca72feb93 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf tools: Fix build on POSIX shells
  latencytop: Fix kconfig dependency warnings
  perf annotate tui: Fix exit and RIGHT keys handling
  tracing: Sanitize value returned from write(trace_marker, "...", len)
  tracing/events: Convert format output to seq_file
  tracing: Extend recordmcount to better support Blackfin mcount
  tracing: Fix ring_buffer_read_page reading out of page boundary
  tracing: Fix an unallocated memory access in function_graph
2010-08-18 09:32:13 -07:00
Nick Piggin
2a4419b5b2 fs: fs_struct rwlock to spinlock
fs: fs_struct rwlock to spinlock

struct fs_struct.lock is an rwlock with the read-side used to protect root and
pwd members while taking references to them. Taking a reference to a path
typically requires just 2 atomic ops, so the critical section is very small.
Parallel read-side operations would have cacheline contention on the lock, the
dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a
real parallelism increase.

Replace it with a spinlock to avoid one or two atomic operations in typical
path lookup fastpath.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:46 -04:00
Linus Torvalds
392abeea52 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  vt,console,kdb: preserve console_blanked while in kdb
  vt: fix regression warnings from KMS merge
  arm,kgdb: fix GDB_MAX_REGS no longer used
  kgdb: add missing __percpu markup in arch/x86/kernel/kgdb.c
  kdb: fix compile error without CONFIG_KALLSYMS
2010-08-17 18:36:19 -07:00
Daniel J Blueman
f362b73244 Fix unprotected access to task credentials in waitid()
Using a program like the following:

	#include <stdlib.h>
	#include <unistd.h>
	#include <sys/types.h>
	#include <sys/wait.h>

	int main() {
		id_t id;
		siginfo_t infop;
		pid_t res;

		id = fork();
		if (id == 0) { sleep(1); exit(0); }
		kill(id, SIGSTOP);
		alarm(1);
		waitid(P_PID, id, &infop, WCONTINUED);
		return 0;
	}

to call waitid() on a stopped process results in access to the child task's
credentials without the RCU read lock being held - which may be replaced in the
meantime - eliciting the following warning:

	===================================================
	[ INFO: suspicious rcu_dereference_check() usage. ]
	---------------------------------------------------
	kernel/exit.c:1460 invoked rcu_dereference_check() without protection!

	other info that might help us debug this:

	rcu_scheduler_active = 1, debug_locks = 1
	2 locks held by waitid02/22252:
	 #0:  (tasklist_lock){.?.?..}, at: [<ffffffff81061ce5>] do_wait+0xc5/0x310
	 #1:  (&(&sighand->siglock)->rlock){-.-...}, at: [<ffffffff810611da>]
	wait_consider_task+0x19a/0xbe0

	stack backtrace:
	Pid: 22252, comm: waitid02 Not tainted 2.6.35-323cd+ #3
	Call Trace:
	 [<ffffffff81095da4>] lockdep_rcu_dereference+0xa4/0xc0
	 [<ffffffff81061b31>] wait_consider_task+0xaf1/0xbe0
	 [<ffffffff81061d15>] do_wait+0xf5/0x310
	 [<ffffffff810620b6>] sys_waitid+0x86/0x1f0
	 [<ffffffff8105fce0>] ? child_wait_callback+0x0/0x70
	 [<ffffffff81003282>] system_call_fastpath+0x16/0x1b

This is fixed by holding the RCU read lock in wait_task_continued() to ensure
that the task's current credentials aren't destroyed between us reading the
cred pointer and us reading the UID from those credentials.

Furthermore, protect wait_task_stopped() in the same way.

We don't need to keep holding the RCU read lock once we've read the UID from
the credentials as holding the RCU read lock doesn't stop the target task from
changing its creds under us - so the credentials may be outdated immediately
after we've read the pointer, lock or no lock.

Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17 18:07:43 -07:00
David Howells
d7627467b7 Make do_execve() take a const filename pointer
Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17 18:07:43 -07:00
Jason Wessel
b590cddfa6 kdb: fix compile error without CONFIG_KALLSYMS
If CONFIG_KGDB_KDB is set and CONFIG_KALLSYMS is not set the kernel
will fail to build with the error:

kernel/built-in.o: In function `kallsyms_symbol_next':
kernel/debug/kdb/kdb_support.c:237: undefined reference to `kdb_walk_kallsyms'
kernel/built-in.o: In function `kallsyms_symbol_complete':
kernel/debug/kdb/kdb_support.c:193: undefined reference to `kdb_walk_kallsyms'

The kdb_walk_kallsyms needs a #ifdef proper header to match the C
implementation.  This patch also fixes the compiler warnings in
kdb_support.c when compiling without CONFIG_KALLSYMS set.  The
compiler warnings are a result of the kallsyms_lookup() macro not
initializing the two of the pass by reference variables.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Reported-by: Michal Simek <monstr@monstr.eu>
2010-08-16 15:58:29 -05:00
Steven Rostedt
d244b6bd41 Merge branch 'tip/perf/urgent-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into trace/tip/perf/urgent-4
Conflicts:
	kernel/trace/trace_events.c

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-16 11:17:30 -04:00
Xiaotian Feng
8d9df9f084 workqueue: free rescuer on destroy_workqueue
wq->rescuer is not freed when wq is destroyed, leads a memory leak
then. This patch also remove a redundant line.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2010-08-16 09:55:01 +02:00
Marcin Slusarz
1aa54bca6e tracing: Sanitize value returned from write(trace_marker, "...", len)
When userspace code writes non-new-line-terminated string to trace_marker
file, write handler appends new-line and returns number of bytes written
to trace buffer, so
write(fd, "abc", 3) will return 4

That's unexpected and unfortunately it confuses glibc's fprintf function.

Example:
int main() {
  fprintf(stderr, "abc");
  return 0;
}

$ gcc test.c -o test
$ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer
$ ./test 2>/sys/kernel/debug/tracing/trace_marker

results in infinite loop:
write(fd, "abc", 3) = 4
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
(...)

...and kernel trace buffer full of empty markers.

Fix it by sanitizing write return value.

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
LKML-Reference: <20100727231801.GB2826@joi.lan>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-13 15:23:16 -04:00
John Stultz
c7dcf87a68 time: Workaround gcc loop optimization that causes 64bit div errors
Early 4.3 versions of gcc apparently aggressively optimize the raw
time accumulation loop, replacing it with a divide.

On 32bit systems, this causes the following link errors:
	undefined reference to `__umoddi3'
	undefined reference to `__udivdi3'

The gcc issue has been fixed in 4.4 and greater.

This patch replaces the accumulation loop with a do_div, as suggested
by Linus.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
CC: Jason Wessel <jason.wessel@windriver.com>
CC: Larry Finger <Larry.Finger@lwfinger.net>
CC: Ingo Molnar <mingo@elte.hu>
CC: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-13 12:03:24 -07:00
Linus Torvalds
2069601b3f Revert "fsnotify: store struct file not struct path"
This reverts commit 3bcf3860a4 (and the
accompanying commit c1e5c95402 "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).

The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.

Fix up various conflicts due to later fsnotify work.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 14:23:04 -07:00
Steven Rostedt
2a37a3df57 tracing/events: Convert format output to seq_file
Two new events were added that broke the current format output.

Both from the SCSI system: scsi_dispatch_cmd_done and scsi_dispatch_cmd_timeout

The reason is that their print_fmt exceeded a page size. Since the output
of the format used simple_read_from_buffer and trace_seq, it was limited
to a page size in output.

This patch converts the printing of the format of an event into seq_file,
which allows greater than a page size to be shown.

I diffed all event formats comparing the output with and without this
patch. All matched except for the above two, which showed just:

  FORMAT TOO BIG

without this patch, but now properly displays the output with this patch.

v2: Remove updating *pos in seq start function.
   [ Thanks to Li Zefan for pointing that out ]

Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com>
Cc: James Bottomley <James.Bottomley@suse.de>
Cc: Tomohiro Kusumi <kusumi.tomohiro@jp.fujitsu.com>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-12 16:59:29 -04:00
Linus Torvalds
26df0766a7 Merge branch 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (22 commits)
  param: don't deref arg in __same_type() checks
  param: update drivers/acpi/debug.c to new scheme
  param: use module_param in drivers/message/fusion/mptbase.c
  ide: use module_param_named rather than module_param_call
  param: update drivers/char/ipmi/ipmi_watchdog.c to new scheme
  param: lock if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes.
  param: lock myri10ge_fw_name against sysfs changes.
  param: simple locking for sysfs-writable charp parameters
  param: remove unnecessary writable charp
  param: add kerneldoc to moduleparam.h
  param: locking for kernel parameters
  param: make param sections const.
  param: use free hook for charp (fix leak of charp parameters)
  param: add a free hook to kernel_param_ops.
  param: silence .init.text references from param ops
  Add param ops struct for hvc_iucv driver.
  nfs: update for module_param_named API change
  AppArmor: update for module_param_named API change
  param: use ops in struct kernel_param, rather than get and set fns directly
  param: move the EXPORT_SYMBOL to after the definitions.
  ...
2010-08-12 10:01:59 -07:00
Jason Wessel
deda2e8196 timekeeping: Fix overflow in rawtime tv_nsec on 32 bit archs
The tv_nsec is a long and when added to the shifted interval it can wrap
and become negative which later causes looping problems in the
getrawmonotonic().  The edge case occurs when the system has slept for
a short period of time of ~2 seconds.

A trace printk of the values in this patch illustrate the problem:

ftrace time stamp: log
43.716079: logarithmic_accumulation: raw: 3d0913 tv_nsec d687faa
43.718513: logarithmic_accumulation: raw: 3d0913 tv_nsec da588bd
43.722161: logarithmic_accumulation: raw: 3d0913 tv_nsec de291d0
46.349925: logarithmic_accumulation: raw: 7a122600 tv_nsec e1f9ae3
46.349930: logarithmic_accumulation: raw: 1e848980 tv_nsec 8831c0e3

The kernel starts looping at 46.349925 in the getrawmonotonic() due to
the negative value from adding the raw value to tv_nsec.

A simple solution is to accumulate into a u64, and then normalize it
to a timespec_t.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
 [ Reworked variable names and simplified some of the code. - John ]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 09:53:39 -07:00
David Howells
12fdff3fc2 Add a dummy printk function for the maintenance of unused printks
Add a dummy printk function for the maintenance of unused printks through gcc
format checking, and also so that side-effect checking is maintained too.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 09:51:35 -07:00
Adrian Hunter
8d57a98ccd block: add secure discard
Secure discard is the same as discard except that all copies of the
discarded sectors (perhaps created by garbage collection) must also be
erased.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:30 -07:00
Stefani Seibold
d78a3eda69 kernel/kfifo.c: add handling of chained scatterlists
The current kfifo scatterlist implementation will not work with chained
scatterlists.  It assumes that struct scatterlist arrays are allocated
contiguously, which is not the case when chained scatterlists (struct
sg_table) are in use.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:29 -07:00
Linus Torvalds
5af568cbd5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  isofs: Fix lseek() to position beyond 4 GB
  vfs: remove unused MNT_STRICTATIME
  vfs: show unreachable paths in getcwd and proc
  vfs: only add " (deleted)" where necessary
  vfs: add prepend_path() helper
  vfs: __d_path: dont prepend the name of the root dentry
  ia64: perfmon: add d_dname method
  vfs: add helpers to get root and pwd
  cachefiles: use path_get instead of lone dget
  fs/sysv/super.c: add support for non-PDP11 v7 filesystems
  V7: Adjust sanity checks for some volumes
  Add v7 alias
  v9fs: fixup for inode_setattr being removed

Manual merge to take Al's version of the fs/sysv/super.c file: it merged
cleanly, but Al had removed an unnecessary header include, so his side
was better.
2010-08-11 09:23:32 -07:00
Stefani Seibold
2e956fb320 kfifo: replace the old non generic API
Simply replace the whole kfifo.c and kfifo.h files with the new generic
version and fix the kerneldoc API template file.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:23 -07:00
Stefani Seibold
4201d9a8e8 kfifo: add the new generic kfifo API
Add the new version of the kfifo API files kfifo.c and kfifo.h.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:23 -07:00
Dan Carpenter
f65a03f6ab kexec: return -EFAULT on copy_to_user() failures
copy_to/from_user() returns the number of bytes remaining to be copied.
It never returns a negative value.  The correct return code is -EFAULT and
not -EIO.

All the callers check for non-zero returns so that's Ok, but the return
code is passed to the user so we should fix this.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Simon Kagstrom <simon.kagstrom@netinsight.net>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:22 -07:00
Anton Blanchard
863a604920 lib/bug.c: add oops end marker to WARN implementation
We are missing the oops end marker for the exception based WARN implementation
in lib/bug.c. This is useful for logfile analysis tools.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:22 -07:00
TAMUKI Shoichi
c7ff0d9c92 panic: keep blinking in spite of long spin timer mode
To keep panic_timeout accuracy when running under a hypervisor, the
current implementation only spins on long time (1 second) calls to mdelay.
 That brings a good effect, but the problem is the keyboard LEDs don't
blink at all on that situation.

This patch changes to call to panic_blink_enter() between every mdelay and
keeps blinking in spite of long spin timer mode.

The time to call to mdelay is now 100ms.  Even this change will keep
panic_timeout accuracy enough when running under a hypervisor.

Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:22 -07:00