Commit Graph

274 Commits

Author SHA1 Message Date
Alexey Dobriyan 33ee3b2e2e kstrto*: converting strings to integers done (hopefully) right
1. simple_strto*() do not contain overflow checks and crufty,
   libc way to indicate failure.
2. strict_strto*() also do not have overflow checks but the name and
   comments pretend they do.
3. Both families have only "long long" and "long" variants,
   but users want strtou8()
4. Both "simple" and "strict" prefixes are wrong:
   Simple doesn't exactly say what's so simple, strict should not exist
   because conversion should be strict by default.

The solution is to use "k" prefix and add convertors for more types.
Enter
	kstrtoull()
	kstrtoll()
	kstrtoul()
	kstrtol()
	kstrtouint()
	kstrtoint()

	kstrtou64()
	kstrtos64()
	kstrtou32()
	kstrtos32()
	kstrtou16()
	kstrtos16()
	kstrtou8()
	kstrtos8()

Include runtime testsuite (somewhat incomplete) as well.

strict_strto*() become deprecated, stubbed to kstrto*() and
eventually will be removed altogether.

Use kstrto*() in code today!

Note: on some archs _kstrtoul() and _kstrtol() are left in tree, even if
      they'll be unused at runtime. This is temporarily solution,
      because I don't want to hardcode list of archs where these
      functions aren't needed. Current solution with sizeof() and
      __alignof__ at least always works.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:14 -07:00
Mandeep Singh Baines 5af5bcb8d3 printk: allow setting DEFAULT_MESSAGE_LEVEL via Kconfig
We've been burned by regressions/bugs which we later realized could have
been triaged quicker if only we'd paid closer attention to dmesg.  To make
it easier to audit dmesg, we'd like to make DEFAULT_MESSAGE_LEVEL
Kconfig-settable.  That way we can set it to KERN_NOTICE and audit any
messages <= KERN_WARNING.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Cc: Olof Johansson <olofj@chromium.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:13 -07:00
Don Zickus fef2c9bc1b kernel/watchdog.c: allow hardlockup to panic by default
When a cpu is considered stuck, instead of limping along and just printing
a warning, it is sometimes preferred to just panic, let kdump capture the
vmcore and reboot.  This gets the machine back into a stable state quickly
while saving the info that got it into a stuck state to begin with.

Add a Kconfig option to allow users to set the hardlockup to panic
by default.  Also add in a 'nmi_watchdog=nopanic' to override this.

[akpm@linux-foundation.org: fix strncmp length]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-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>
2011-03-22 17:44:12 -07:00
Linus Torvalds eddecbb601 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  kbuild: Make DEBUG_SECTION_MISMATCH selectable, but not on by default
  genksyms: Regenerate lexer and parser
  genksyms: Track changes to enum constants
  genksyms: simplify usage of find_symbol()
  genksyms: Add helpers for building string lists
  genksyms: Simplify printing of symbol types
  genksyms: Simplify lexer
  genksyms: Do not paste the bison header file to lex.c
  modpost: fix trailing comma
  KBuild: silence "'scripts/unifdef' is up to date."
  kbuild: Add extra gcc checks
  kbuild: reenable section mismatch analysis
  unifdef: update to upstream version 2.5
2011-03-21 15:55:26 -07:00
Michal Marek f2c23f65f6 kbuild: Make DEBUG_SECTION_MISMATCH selectable, but not on by default
CONFIG_DEBUG_SECTION_MISMATCH has also runtime effects due to the
-fno-inline-functions-called-once compiler flag, so forcing it on
everyone is not a good idea.

Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-03-21 10:47:58 +01:00
Arnd Bergmann 4ba8216cd9 BKL: That's all, folks
This removes the implementation of the big kernel lock,
at last. A lot of people have worked on this in the
past, I so the credit for this patch should be with
everyone who participated in the hunt.

The names on the Cc list are the people that were the
most active in this, according to the recorded git
history, in alphabetical order.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Alessio Igor Bogani <abogani@texware.it>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jan Blunck <jblunck@infradead.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Paul Menage <menage@google.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-05 10:56:00 +01:00
Uwe Kleine-König de933bd833 kbuild: reenable section mismatch analysis
This was disabled in commit

	e5f95c8 (kbuild: print only total number of section mismatces found)

because there were too many warnings.  Now we're down to a reasonable
number again, so we start scaring people with the details.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-02-24 15:26:43 +01:00
Geert Uytterhoeven 7302041556 m68knommu: Remove dependencies on nonexistent M68KNOMMU
M68KNOMMU is set nowhere.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
2011-02-08 15:07:44 +10:00
David Rientjes 6a108a14fa kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option
is used to configure any non-standard kernel with a much larger scope than
only small devices.

This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes
references to the option throughout the kernel.  A new CONFIG_EMBEDDED
option is added that automatically selects CONFIG_EXPERT when enabled and
can be used in the future to isolate options that should only be
considered for embedded systems (RISC architectures, SLOB, etc).

Calling the option "EXPERT" more accurately represents its intention: only
expert users who understand the impact of the configuration changes they
are making should enable it.

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: David Woodhouse <david.woodhouse@intel.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Greg KH <gregkh@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robin Holt <holt@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:05 -08:00
Don Zickus 4a7863cc2e x86, nmi_watchdog: Remove ARCH_HAS_NMI_WATCHDOG and rely on CONFIG_HARDLOCKUP_DETECTOR
The x86 arch has shifted its use of the nmi_watchdog from a
local implementation to the global one provide by
kernel/watchdog.c.  This shift has caused a whole bunch of
compile problems under different config options.  I attempt to
simplify things with the patch below.

In order to simplify things, I had to come to terms with the
meaning of two terms ARCH_HAS_NMI_WATCHDOG and
CONFIG_HARDLOCKUP_DETECTOR.  Basically they mean the same thing,
the former on a local level and the latter on a global level.

With the old x86 nmi watchdog gone, there is no need to rely on
defining the ARCH_HAS_NMI_WATCHDOG variable because it doesn't
make sense any more.  x86 will now use the global
implementation.

The changes below do a few things.  First it changes the few
places that relied on ARCH_HAS_NMI_WATCHDOG to use
CONFIG_X86_LOCAL_APIC (the former was an alias for the latter
anyway, so nothing unusual here).  Those pieces of code were
relying more on local apic functionality the nmi watchdog
functionality, so the change should make sense.

Second, I removed the x86 implementation of
touch_nmi_watchdog().  It isn't need now, instead x86 will rely
on kernel/watchdog.c's implementation.

Third, I removed the #define ARCH_HAS_NMI_WATCHDOG itself from
x86.  And tweaked the include/linux/nmi.h file to tell users to
look for an externally defined touch_nmi_watchdog in the case of
ARCH_HAS_NMI_WATCHDOG _or_ CONFIG_HARDLOCKUP_DETECTOR. This
changes removes some of the ugliness in that file.

Finally, I added a Kconfig dependency for
CONFIG_HARDLOCKUP_DETECTOR that said you can't have
ARCH_HAS_NMI_WATCHDOG _and_ CONFIG_HARDLOCKUP_DETECTOR.  You can
only have one nmi_watchdog.

Tested with
ARCH=i386: allnoconfig, defconfig, allyesconfig, (various broken
configs) ARCH=x86_64: allnoconfig, defconfig, allyesconfig,
(various broken configs)

Hopefully, after this patch I won't get any more compile broken
emails. :-)

v3:
  changed a couple of 'linux/nmi.h' -> 'asm/nmi.h' to pick-up correct function
  prototypes when CONFIG_HARDLOCKUP_DETECTOR is not set.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1293044403-14117-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-22 22:15:32 +01:00
Linus Torvalds e3e1288e86 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (48 commits)
  DMAENGINE: move COH901318 to arch_initcall
  dma: imx-dma: fix signedness bug
  dma/timberdale: simplify conditional
  ste_dma40: remove channel_type
  ste_dma40: remove enum for endianess
  ste_dma40: remove TIM_FOR_LINK option
  ste_dma40: move mode_opt to separate config
  ste_dma40: move channel mode to a separate field
  ste_dma40: move priority to separate field
  ste_dma40: add variable to indicate valid dma_cfg
  async_tx: make async_tx channel switching opt-in
  move async raid6 test to lib/Kconfig.debug
  dmaengine: Add Freescale i.MX1/21/27 DMA driver
  intel_mid_dma: change the slave interface
  intel_mid_dma: fix the WARN_ONs
  intel_mid_dma: Add sg list support to DMA driver
  intel_mid_dma: Allow DMAC2 to share interrupt
  intel_mid_dma: Allow IRQ sharing
  intel_mid_dma: Add runtime PM support
  DMAENGINE: define a dummy filter function for ste_dma40
  ...
2010-10-27 19:04:36 -07:00
Linus Torvalds e404f91ed2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: convert a BUG_ON to BUILD_BUG_ON
  arch/tile: make ptrace() work properly for TILE-Gx COMPAT mode
  arch/tile: support new info op generated by compiler
  arch/tile: minor whitespace/naming changes for string support files
  arch/tile: enable single-step support for TILE-Gx
  arch/tile: parameterize system PLs to support KVM port
  arch/tile: add Tilera's <arch/sim.h> header as an open-source header
  arch/tile: Bomb C99 comments to C89 comments in tile's <arch/sim_def.h>
  arch/tile: prevent corrupt top frame from causing backtracer runaway
  arch/tile: various top-level Makefile cleanups
  arch/tile: change lower bound on syscall error return to -4095
  arch/tile: properly export __mb_incoherent for modules
  arch/tile: provide a definition of MAP_STACK
  kmemleak: add TILE to the list of supported architectures.
  char: hvc: check for error case
  arch/tile: Add a warning if we try to allocate too much vmalloc memory.
  arch/tile: update some comments to clarify register usage.
  arch/tile: use better "punctuation" for VMSPLIT_3_5G and friends
  arch/tile: Use <asm-generic/syscalls.h>
  tile: replace some BUG_ON checks with BUILD_BUG_ON checks
2010-10-26 17:25:38 -07:00
Artem Bityutskiy 6d411e6c01 lib/Kconfig.debug: add list_sort debugging switch
While hunting a non-existing bug in 'list_sort()', I've improved the
'list_sort_test()' function which tests the 'list_sort()' library call.
Although at the end I found a bug in my code, but not in 'list_sort()', I
think my clean-ups and improvements are worth merging because they make
the test function better.

This patch:

Make the self-tests selectable via Kconfig rather than by manual enabling
of DEBUG_LIST_SORT.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: Don Mullis <don.mullis@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:18 -07:00
Tejun Heo e2852ae825 percpu_counter: add debugobj support
All percpu counters are linked to a global list on initialization and
removed from it on destruction.  The list is walked during CPU up/down.
If a percpu counter is freed without being properly destroyed, the system
will oops only on the next CPU up/down making it pretty nasty to track
down.  This patch adds debugobj support for percpu counters so that such
problems can be found easily.

As percpu counters don't make sense on stack and can't be statically
initialized, debugobj support is pretty simple.  It's initialized and
activated on counter initialization, and deactivatd and destroyed on
counter destruction.  With this patch applied, the bug fixed by commit
602586a83b (shmem: put_super must
percpu_counter_destroy) triggers the following warning on tmpfs unmount
and the system won't oops on the next cpu up/down operation.

 ------------[ cut here ]------------
 WARNING: at lib/debugobjects.c:259 debug_print_object+0x5c/0x70()
 Hardware name: Bochs
 ODEBUG: free active (active state 0) object type: percpu_counter
 Modules linked in:
 Pid: 3999, comm: umount Not tainted 2.6.36-rc2-work+ #5
 Call Trace:
  [<ffffffff81083f7f>] warn_slowpath_common+0x7f/0xc0
  [<ffffffff81084076>] warn_slowpath_fmt+0x46/0x50
  [<ffffffff813b45cc>] debug_print_object+0x5c/0x70
  [<ffffffff813b50e5>] debug_check_no_obj_freed+0x125/0x210
  [<ffffffff811577d3>] kfree+0xb3/0x2f0
  [<ffffffff81132edd>] shmem_put_super+0x1d/0x30
  [<ffffffff81162e96>] generic_shutdown_super+0x56/0xe0
  [<ffffffff81162f86>] kill_anon_super+0x16/0x60
  [<ffffffff81162ff7>] kill_litter_super+0x27/0x30
  [<ffffffff81163295>] deactivate_locked_super+0x45/0x60
  [<ffffffff81163cfa>] deactivate_super+0x4a/0x70
  [<ffffffff8117d446>] mntput_no_expire+0x86/0xe0
  [<ffffffff8117df7f>] sys_umount+0x6f/0x360
  [<ffffffff8103f01b>] system_call_fastpath+0x16/0x1b
 ---[ end trace cce2a341ba3611a7 ]---

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Thomas Gleixner <tglxlinutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:18 -07:00
Pekka Enberg 6d4121f6c2 Merge branch 'master' into for-linus
Conflicts:
	include/linux/percpu.h
	mm/percpu.c
2010-10-24 19:57:05 +03:00
Linus Torvalds 5704e44d28 Merge branch 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
* 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  BKL: introduce CONFIG_BKL.
  dabusb: remove the BKL
  sunrpc: remove the big kernel lock
  init/main.c: remove BKL notations
  blktrace: remove the big kernel lock
  rtmutex-tester: make it build without BKL
  dvb-core: kill the big kernel lock
  dvb/bt8xx: kill the big kernel lock
  tlclk: remove big kernel lock
  fix rawctl compat ioctls breakage on amd64 and itanic
  uml: kill big kernel lock
  parisc: remove big kernel lock
  cris: autoconvert trivial BKL users
  alpha: kill big kernel lock
  isapnp: BKL removal
  s390/block: kill the big kernel lock
  hpet: kill BKL, add compat_ioctl
2010-10-22 10:43:11 -07:00
Linus Torvalds 5d70f79b5e Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (163 commits)
  tracing: Fix compile issue for trace_sched_wakeup.c
  [S390] hardirq: remove pointless header file includes
  [IA64] Move local_softirq_pending() definition
  perf, powerpc: Fix power_pmu_event_init to not use event->ctx
  ftrace: Remove recursion between recordmcount and scripts/mod/empty
  jump_label: Add COND_STMT(), reducer wrappery
  perf: Optimize sw events
  perf: Use jump_labels to optimize the scheduler hooks
  jump_label: Add atomic_t interface
  jump_label: Use more consistent naming
  perf, hw_breakpoint: Fix crash in hw_breakpoint creation
  perf: Find task before event alloc
  perf: Fix task refcount bugs
  perf: Fix group moving
  irq_work: Add generic hardirq context callbacks
  perf_events: Fix transaction recovery in group_sched_in()
  perf_events: Fix bogus AMD64 generic TLB events
  perf_events: Fix bogus context time tracking
  tracing: Remove parent recording in latency tracer graph options
  tracing: Use one prologue for the preempt irqs off tracer function tracers
  ...
2010-10-21 12:54:49 -07:00
Arnd Bergmann 6de5bd128d BKL: introduce CONFIG_BKL.
With all the patches we have queued in the BKL removal tree, only a
few dozen modules are left that actually rely on the BKL, and even
there are lots of low-hanging fruit. We need to decide what to do
about them, this patch illustrates one of the options:

Every user of the BKL is marked as 'depends on BKL' in Kconfig,
and the CONFIG_BKL becomes a user-visible option. If it gets
disabled, no BKL using module can be built any more and the BKL
code itself is compiled out.

The one exception is file locking, which is practically always
enabled and does a 'select BKL' instead. This effectively forces
CONFIG_BKL to be enabled until we have solved the fs/lockd
mess and can apply the patch that removes the BKL from fs/locks.c.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2010-10-21 15:44:13 +02:00
Chris Metcalf 6b945df742 kmemleak: add TILE to the list of supported architectures.
All the necessary functionality was already there; we just need
to make it possible to select the config option.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-10-14 14:54:47 -04:00
Dan Williams 400fb7f6a0 move async raid6 test to lib/Kconfig.debug
The prompt for "Self test for hardware accelerated raid6 recovery" does not
belong in the top level configuration menu.  All the options in
crypto/async_tx/Kconfig are selected and do not depend on CRYPTO.
Kconfig.debug seems like a reasonable fit.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2010-10-07 15:25:04 -07:00
Christoph Lameter ab4d5ed5ee slub: Enable sysfs support for !CONFIG_SLUB_DEBUG
Currently disabling CONFIG_SLUB_DEBUG also disabled SYSFS support meaning
that the slabs cannot be tuned without DEBUG.

Make SYSFS support independent of CONFIG_SLUB_DEBUG

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-06 16:54:36 +03:00
Paul E. McKenney 2dfbf4dfbe rcu: Add advice to PROVE_RCU_REPEATEDLY kernel config parameter
The PROVE_RCU_REPEATEDLY has no "Say Y"/"Say N" advice, so this commit
adds it.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-09-23 09:16:54 -07:00
Steven Rostedt 46b93b74fc tracing/lockdep: Fix dependency of TRACE_IRQFLAGS
When CONFIG_IRQSOFF_TRACER is set and CONFIG_PROVE_LOCKING is not, we
get the following error:

$  make oldconfig
scripts/kconfig/conf --oldconfig arch/x86/Kconfig
warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE && TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)
warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE && TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)

This is because IRQSOFF_TRACER selects TRACE_IRQFLAGS but TRACE_IRQFLAGS
has PROVE_LOCKING as a dependency. This code is incorrect, and
this patch changes the TRACE_IRQFLAGS to be just a simple bool that
does not depend or select anything. Instead both IRQSOFF_TRACER and
PROVE_LOCKING select it.

Reported-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-31 16:35:20 -04:00
Paul E. McKenney 910b1b7e19 rcu: Allow RCU CPU stall warnings to be off at boot, but manually enablable
Currently, if RCU CPU stall warnings are enabled, they are enabled
immediately upon boot.  They can be manually disabled via /sys (and
also re-enabled via /sys), and are automatically disabled upon panic.
However, some users need RCU CPU stalls to be disabled at boot time,
but to be enabled without rebuilding/rebooting.  For example, someone
running a real-time application in production might not want the
additional latency of RCU CPU stall detection in normal operation, but
might need to enable it at any point for fault isolation purposes.

This commit therefore provides a new CONFIG_RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel configuration parameter that maintains the current behavior
(enable at boot) by default, but allows a kernel to be configured
with RCU CPU stall detection built into the kernel, but disabled at
boot time.

Requested-by: Clark Williams <williams@redhat.com>
Requested-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-08-19 17:18:04 -07:00
Paul E. McKenney b163760e37 rcu: make CPU stall warning timeout configurable
Also set the default to 60 seconds, up from the previous hard-coded timeout
of 10 seconds.  This allows people who care to set short timeouts, while
avoiding people with unusual configurations (make randconfig!!!) from being
bothered with spurious CPU stall warnings.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:02 -07:00
Paul E. McKenney ca5ecddfa8 rcu: define __rcu address space modifier for sparse
This commit provides definitions for the __rcu annotation defined earlier.
This annotation permits sparse to check for correct use of RCU-protected
pointers.  If a pointer that is annotated with __rcu is accessed
directly (as opposed to via rcu_dereference(), rcu_assign_pointer(),
or one of their variants), sparse can be made to complain.  To enable
such complaints, use the new default-disabled CONFIG_SPARSE_RCU_POINTER
kernel configuration option.  Please note that these sparse complaints are
intended to be a debugging aid, -not- a code-style-enforcement mechanism.

There are special rcu_dereference_protected() and rcu_access_pointer()
accessors for use when RCU read-side protection is not required, for
example, when no other CPU has access to the data structure in question
or while the current CPU hold the update-side lock.

This patch also updates a number of docbook comments that were showing
their age.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christopher Li <sparse@chrisli.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:17:59 -07:00
Randy Dunlap 625fdcaa6d latencytop: Fix kconfig dependency warnings
warning: (LATENCYTOP && HAVE_LATENCYTOP_SUPPORT) selects
SCHED_DEBUG which has unmet direct dependencies (DEBUG_KERNEL &&
PROC_FS) warning: (LATENCYTOP && HAVE_LATENCYTOP_SUPPORT) selects
SCHEDSTATS which has unmet direct dependencies (DEBUG_KERNEL && PROC_FS)

Add depends on STACKTRACE_SUPPORT for 'select STACKTRACE'.
Add depends on PROC_FS since that is where the output goes.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20100812123121.a7c99cde.randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-17 09:09:03 +02:00
Linus Torvalds 4c619407b0 Merge branch 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-2.6-cm
* 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-2.6-cm:
  kmemleak: Fix typo in the comment
  lib/scatterlist: Hook sg_kmalloc into kmemleak (v2)
  kmemleak: Add DocBook style comments to kmemleak.c
  kmemleak: Introduce a default off mode for kmemleak
  kmemleak: Show more information for objects found by alias
2010-08-10 13:58:11 -07:00
Linus Torvalds ab69bcd66f Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (28 commits)
  driver core: device_rename's new_name can be const
  sysfs: Remove owner field from sysfs struct attribute
  powerpc/pci: Remove owner field from attribute initialization in PCI bridge init
  regulator: Remove owner field from attribute initialization in regulator core driver
  leds: Remove owner field from attribute initialization in bd2802 driver
  scsi: Remove owner field from attribute initialization in ARCMSR driver
  scsi: Remove owner field from attribute initialization in LPFC driver
  cgroupfs: create /sys/fs/cgroup to mount cgroupfs on
  Driver core: Add BUS_NOTIFY_BIND_DRIVER
  driver core: fix memory leak on one error path in bus_register()
  debugfs: no longer needs to depend on SYSFS
  sysfs: Fix one more signature discrepancy between sysfs implementation and docs.
  sysfs: fix discrepancies between implementation and documentation
  dcdbas: remove a redundant smi_data_buf_free in dcdbas_exit
  dmi-id: fix a memory leak in dmi_id_init error path
  sysfs: sysfs_chmod_file's attr can be const
  firmware: Update hotplug script
  Driver core: move platform device creation helpers to .init.text (if MODULE=n)
  Driver core: reduce duplicated code for platform_device creation
  Driver core: use kmemdup in platform_device_add_resources
  ...
2010-08-06 11:36:30 -07:00
Linus Torvalds 4aed2fd8e3 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (162 commits)
  tracing/kprobes: unregister_trace_probe needs to be called under mutex
  perf: expose event__process function
  perf events: Fix mmap offset determination
  perf, powerpc: fsl_emb: Restore setting perf_sample_data.period
  perf, powerpc: Convert the FSL driver to use local64_t
  perf tools: Don't keep unreferenced maps when unmaps are detected
  perf session: Invalidate last_match when removing threads from rb_tree
  perf session: Free the ref_reloc_sym memory at the right place
  x86,mmiotrace: Add support for tracing STOS instruction
  perf, sched migration: Librarize task states and event headers helpers
  perf, sched migration: Librarize the GUI class
  perf, sched migration: Make the GUI class client agnostic
  perf, sched migration: Make it vertically scrollable
  perf, sched migration: Parameterize cpu height and spacing
  perf, sched migration: Fix key bindings
  perf, sched migration: Ignore unhandled task states
  perf, sched migration: Handle ignored migrate out events
  perf: New migration tool overview
  tracing: Drop cpparg() macro
  perf: Use tracepoint_synchronize_unregister() to flush any pending tracepoint call
  ...

Fix up trivial conflicts in Makefile and drivers/cpufreq/cpufreq.c
2010-08-06 09:30:52 -07:00
Linus Torvalds 3a3527b646 Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  Revert "net: Make accesses to ->br_port safe for sparse RCU"
  mce: convert to rcu_dereference_index_check()
  net: Make accesses to ->br_port safe for sparse RCU
  vfs: add fs.h to define struct file
  lockdep: Add an in_workqueue_context() lockdep-based test function
  rcu: add __rcu API for later sparse checking
  rcu: add an rcu_dereference_index_check()
  tree/tiny rcu: Add debug RCU head objects
  mm: remove all rcu head initializations
  fs: remove all rcu head initializations, except on_stack initializations
  powerpc: remove all rcu head initializations
2010-08-06 09:23:07 -07:00
Linus Torvalds da9e82b3b8 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  modpost: support objects with more than 64k sections
  trivial: fix a typo in a filename
  frv: clean up arch/frv/Makefile
  kbuild: allow assignment to {A,C}FLAGS_KERNEL on the command line
  kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line
  Kbuild: Add option to set -femit-struct-debug-baseonly
  Makefile: "make kernelrelease" should show the correct full kernel version
  Makefile.build: make KBUILD_SYMTYPES work again
2010-08-05 14:10:07 -07:00
Randy Dunlap c462e8cd57 debugfs: no longer needs to depend on SYSFS
debugfs no longer uses 'kernel_subsys' (which is gone), and other
kernel/ksysfs.c code is always built, so DEBUG_FS does not need
to depend on SYSFS.

Fixes this kconfig warning:

warning: (TREE_RCU_TRACE || AMD_IOMMU_STATS && AMD_IOMMU || MTD_UBI_DEBUG && MTD && SYSFS && MTD_UBI || UBIFS_FS_DEBUG && MISC_FILESYSTEMS && UBIFS_FS || DEBUG_KMEMLEAK && DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE) && SYSFS || TRACING || X86_PTDUMP && DEBUG_KERNEL || BLK_DEV_IO_TRACE && TRACING_SUPPORT && FTRACE && SYSFS && BLOCK) selects DEBUG_FS which has unmet direct dependencies (SYSFS)

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-08-05 13:53:34 -07:00
Linus Torvalds bbc4fd12a6 Merge branch 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze
* 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze: (49 commits)
  microblaze: Add KGDB support
  microblaze: Support brki rX, 0x18 for user application debugging
  microblaze: Remove nop after MSRCLR/SET, MTS, MFS instructions
  microblaze: Simplify syscall rutine
  microblaze: Move PT_MODE saving to delay slot
  microblaze: Fix _interrupt function
  microblaze: Fix _user_exception function
  microblaze: Put together addik instructions
  microblaze: Use delay slot in syscall macros
  microblaze: Save kernel mode in delay slot
  microblaze: Do not mix register saving and mode setting
  microblaze: Move SAVE_STATE upward
  microblaze: entry.S: Macro optimization
  microblaze: Optimize hw exception rutine
  microblaze: Implement clear_ums macro and fix SAVE_STATE macro
  microblaze: Remove additional setup for kernel_mode
  microblaze: Optimize SAVE_STATE macro
  microblaze: Remove additional loading
  microblaze: Completely remove working with R11 register
  microblaze: Do not setup BIP in _debug_exception
  ...
2010-08-05 08:59:22 -07:00
Ingo Molnar 61be7fdec2 Merge branch 'perf/nmi' into perf/core
Conflicts:
	kernel/Makefile

Merge reason: Add the now complete topic, fix the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-05 08:45:05 +02:00
Michal Marek 772320e845 Merge commit 'v2.6.35' into kbuild/kbuild
Conflicts:
	arch/powerpc/Makefile
2010-08-04 13:59:13 +02:00
Michal Simek 79aac88903 microblaze: Disable FRAME_POINTER selection
Microblaze doesn't support frame pointers. Ftrace code
uses CALLER_ADDR1 which is defined in linux/ftrace.h. For Microblaze
is 0.

Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-08-04 10:22:32 +02:00
Takuya Yoshikawa f4d0143951 Kconfig.debug: FAIL_IO_TIMEOUT: typo Faul -> Fault
The last 't' of 'fault' is missing in the description of FAIL_IO_TIMEOUT.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-07-21 10:36:50 +02:00
Jason Baron ab0155a22a kmemleak: Introduce a default off mode for kmemleak
Introduce a new DEBUG_KMEMLEAK_DEFAULT_OFF config parameter that allows
kmemleak to be disabled by default, but enabled on the command line
via: kmemleak=on. Although a reboot is required to turn it on, its still
useful to not require a re-compile.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
2010-07-19 11:54:17 +01:00
Andi Kleen d6f4ceb796 Kbuild: Add option to set -femit-struct-debug-baseonly
Newer gcc has a -femit-struct-debug-baseonly option that dramatically
reduces the size of object files with debug info. What it does
is to only emit type information for structures when the structures
are defined in the same file or in a header file.

This means the type information for most headers are not included.
This is not good when the type information is actually
needed (e.g. with kgdb or systemtap)

But often kernel hackers only care about line numbers and don't
need all the type information anyways. In this case setting
the option can be a big win:

A build dir for a specific x86-64 configuration with gcc 4.5
shrunk from 2.3G to 1.2G. The compilation was also nearly a minute
faster.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
[mmarek: reformatted help text]
Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-07-14 17:21:28 +02:00
Mathieu Desnoyers 551d55a944 tree/tiny rcu: Add debug RCU head objects
Helps finding racy users of call_rcu(), which results in hangs because list
entries are overwritten and/or skipped.

Changelog since v4:
- Bissectability is now OK
- Now generate a WARN_ON_ONCE() for non-initialized rcu_head passed to
  call_rcu(). Statically initialized objects are detected with
  object_is_static().
- Rename rcu_head_init_on_stack to init_rcu_head_on_stack.
- Remove init_rcu_head() completely.

Changelog since v3:
- Include comments from Lai Jiangshan

This new patch version is based on the debugobjects with the newly introduced
"active state" tracker.

Non-initialized entries are all considered as "statically initialized". An
activation fixup (triggered by call_rcu()) takes care of performing the debug
object initialization without issuing any warning. Since we cannot increase the
size of struct rcu_head, I don't see much room to put an identifier for
statically initialized rcu_head structures. So for now, we have to live without
"activation without explicit init" detection. But the main purpose of this debug
option is to detect double-activations (double call_rcu() use of a rcu_head
before the callback is executed), which is correctly addressed here.

This also detects potential internal RCU callback corruption, which would cause
the callbacks to be executed twice.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: David S. Miller <davem@davemloft.net>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: akpm@linux-foundation.org
CC: mingo@elte.hu
CC: laijs@cn.fujitsu.com
CC: dipankar@in.ibm.com
CC: josh@joshtriplett.org
CC: dvhltc@us.ibm.com
CC: niv@us.ibm.com
CC: tglx@linutronix.de
CC: peterz@infradead.org
CC: rostedt@goodmis.org
CC: Valdis.Kletnieks@vt.edu
CC: dhowells@redhat.com
CC: eric.dumazet@gmail.com
CC: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2010-06-14 16:37:26 -07:00
Akinobu Mita c9d221f86e fault-injection: add CPU notifier error injection module
I used this module to test the series of modification to the cpu notifiers
code.

Example1: inject CPU offline error (-1 == -EPERM)

	# modprobe cpu-notifier-error-inject cpu_down_prepare_error=-1
	# echo 0 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: Operation not permitted

Example2: inject CPU online error (-2 == -ENOENT)

	# modprobe cpu-notifier-error-inject cpu_up_prepare_error=-2
	# echo 1 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: No such file or directory

[akpm@linux-foundation.org: fix Kconfig help text]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:48 -07:00
Florian Ragwitz 2b2f68b538 DYNAMIC_DEBUG: fix documentation errors
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Florian Ragwitz <rafl@debian.org>
Cc: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:05 -07:00
Frederic Weisbecker e35e7fb0e9 lockup_detector: Don't enable the lockup detector by default
The lockup detector is a new feature that now involves the
nmi watchdog. Drop the default y and let the user choose.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
2010-05-19 11:36:49 +02:00
Linus Torvalds 93c9d7f60c Merge branch 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix LOCK_PREFIX_HERE for uniprocessor build
  x86, atomic64: In selftest, distinguish x86-64 from 586+
  x86-32: Fix atomic64_inc_not_zero return value convention
  lib: Fix atomic64_inc_not_zero test
  lib: Fix atomic64_add_unless return value convention
  x86-32: Fix atomic64_add_unless return value convention
  lib: Fix atomic64_add_unless test
  x86: Implement atomic[64]_dec_if_positive()
  lib: Only test atomic64_dec_if_positive on archs having it
  x86-32: Rewrite 32-bit atomic64 functions in assembly
  lib: Add self-test for atomic64_t
  x86-32: Allow UP/SMP lock replacement in cmpxchg64
  x86: Add support for lock prefix in alternatives
2010-05-18 08:40:05 -07:00
Frederic Weisbecker 23637d477c lockup_detector: Introduce CONFIG_HARDLOCKUP_DETECTOR
This new config is deemed to simplify even more the lockup detector
dependencies and can make it easier to bring a smooth sorting
between archs that support the new generic lockup detector and those
that still have their own, especially for those that are in the
middle of this migration.

Instead of checking whether we have CONFIG_LOCKUP_DETECTOR +
CONFIG_PERF_EVENTS_NMI each time an arch wants to know if it needs
to build its own lockup detector, take a shortcut with this new
config. It is enabled only if the hardlockup detection part of
the whole lockup detector is on.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
2010-05-16 01:57:42 +02:00
Frederic Weisbecker e16bb1d7fe lockup_detector: Update some config
We kept CONFIG_DETECT_SOFTLOCKUP around for compatibility with
older configs. But it was enabled by default if CONFIG_DEBUG_KERNEL.

So if we want to enable CONFIG_LOCKUP_DETECTOR on configs that had
CONFIG_DETECT_SOFTLOCKUP, all we need is to have the same enabling
by default if CONFIG_DEBUG_KERNEL. We can then remove
CONFIG_DETECT_SOFTLOCKUP directly.

So tag CONFIG_LOCKUP_DETECTOR as default y. This is what we want for
most serious kernel debugging anyway.

And also forbid the lockup detector in S390 as it was for the
previous softlockup detector, event though the true reason for that
is not outlined.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
2010-05-16 01:57:27 +02:00
Frederic Weisbecker 89d7ce2a21 lockup_detector: Make BOOTPARAM_SOFTLOCKUP_PANIC depend on LOCKUP_DETECTOR
Panic on softlockups was still depending on the softlockup detector.
But the latter has been merged into the lockup detector now.

Let's update this config dependency.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
2010-05-13 00:27:20 +02:00
Don Zickus 58687acba5 lockup_detector: Combine nmi_watchdog and softlockup detector
The new nmi_watchdog (which uses the perf event subsystem) is very
similar in structure to the softlockup detector.  Using Ingo's
suggestion, I combined the two functionalities into one file:
kernel/watchdog.c.

Now both the nmi_watchdog (or hardlockup detector) and softlockup
detector sit on top of the perf event subsystem, which is run every
60 seconds or so to see if there are any lockups.

To detect hardlockups, cpus not responding to interrupts, I
implemented an hrtimer that runs 5 times for every perf event
overflow event.  If that stops counting on a cpu, then the cpu is
most likely in trouble.

To detect softlockups, tasks not yielding to the scheduler, I used the
previous kthread idea that now gets kicked every time the hrtimer fires.
If the kthread isn't being scheduled neither is anyone else and the
warning is printed to the console.

I tested this on x86_64 and both the softlockup and hardlockup paths
work.

V2:
- cleaned up the Kconfig and softlockup combination
- surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI
- seperated out the softlockup case from perf event subsystem
- re-arranged the enabling/disabling nmi watchdog from proc space
- added cpumasks for hardlockup failure cases
- removed fallback to soft events if no PMU exists for hard events

V3:
- comment cleanups
- drop support for older softlockup code
- per_cpu cleanups
- completely remove software clock base hardlockup detector
- use per_cpu masking on hard/soft lockup detection
- #ifdef cleanups
- rename config option NMI_WATCHDOG to LOCKUP_DETECTOR
- documentation additions

V4:
- documentation fixes
- convert per_cpu to __get_cpu_var
- powerpc compile fixes

V5:
- split apart warn flags for hard and soft lockups

TODO:
- figure out how to make an arch-agnostic clock2cycles call
  (if possible) to feed into perf events as a sample period

[fweisbec: merged conflict patch]

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-12 23:55:33 +02:00
Frederic Weisbecker a9aa1d02de Merge commit 'v2.6.34-rc7' into perf/nmi
Merge reason: catch up with latest softlockup detector changes.
2010-05-12 23:20:33 +02:00