Commit Graph

16970 Commits

Author SHA1 Message Date
Ingo Molnar
bb799d3b98 Merge tag 'v3.13-rc4' into core/locking
Merge Linux 3.13-rc4, to refresh this rather old tree with the latest fixes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-17 15:27:08 +01:00
Paul E. McKenney
6303b9c87d rcu: Apply smp_mb__after_unlock_lock() to preserve grace periods
RCU must ensure that there is the equivalent of a full memory
barrier between any memory access preceding grace period and any
memory access following that same grace period, regardless of
which CPU(s) happen to execute the two memory accesses.
Therefore, downgrading UNLOCK+LOCK to no longer imply a full
memory barrier requires some adjustments to RCU.

This commit therefore adds smp_mb__after_unlock_lock()
invocations as needed after the RCU lock acquisitions that need
to be part of a full-memory-barrier UNLOCK+LOCK.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-7-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-16 11:36:16 +01:00
Linus Torvalds
9199c4caa1 Merge tag 'pci-v3.13-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI updates from Bjorn Helgaas:
 "PCI device hotplug
    - Move device_del() from pci_stop_dev() to pci_destroy_dev() (Rafael
      Wysocki)

  Host bridge drivers
    - Update maintainers for DesignWare, i.MX6, Armada, R-Car (Bjorn
      Helgaas)
    - mvebu: Return 'unsupported' for Interrupt Line and Interrupt Pin
      (Jason Gunthorpe)

  Miscellaneous
    - Avoid unnecessary CPU switch when calling .probe() (Alexander
      Duyck)
    - Revert "workqueue: allow work_on_cpu() to be called recursively"
      (Bjorn Helgaas)
    - Disable Bus Master only on kexec reboot (Khalid Aziz)
    - Omit PCI ID macro strings to shorten quirk names for LTO (Michal
      Marek)"

* tag 'pci-v3.13-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  MAINTAINERS: Add DesignWare, i.MX6, Armada, R-Car PCI host maintainers
  PCI: Disable Bus Master only on kexec reboot
  PCI: mvebu: Return 'unsupported' for Interrupt Line and Interrupt Pin
  PCI: Omit PCI ID macro strings to shorten quirk names
  PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev()
  Revert "workqueue: allow work_on_cpu() to be called recursively"
  PCI: Avoid unnecessary CPU switch when calling driver .probe() method
2013-12-15 11:45:27 -08:00
Linus Torvalds
5dec682c7f Merge tag 'keys-devel-20131210' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull misc keyrings fixes from David Howells:
 "These break down into five sets:

   - A patch to error handling in the big_key type for huge payloads.
     If the payload is larger than the "low limit" and the backing store
     allocation fails, then big_key_instantiate() doesn't clear the
     payload pointers in the key, assuming them to have been previously
     cleared - but only one of them is.

     Unfortunately, the garbage collector still calls big_key_destroy()
     when sees one of the pointers with a weird value in it (and not
     NULL) which it then tries to clean up.

   - Three patches to fix the keyring type:

     * A patch to fix the hash function to correctly divide keyrings off
       from keys in the topology of the tree inside the associative
       array.  This is only a problem if searching through nested
       keyrings - and only if the hash function incorrectly puts the a
       keyring outside of the 0 branch of the root node.

     * A patch to fix keyrings' use of the associative array.  The
       __key_link_begin() function initially passes a NULL key pointer
       to assoc_array_insert() on the basis that it's holding a place in
       the tree whilst it does more allocation and stuff.

       This is only a problem when a node contains 16 keys that match at
       that level and we want to add an also matching 17th.  This should
       easily be manufactured with a keyring full of keyrings (without
       chucking any other sort of key into the mix) - except for (a)
       above which makes it on average adding the 65th keyring.

     * A patch to fix searching down through nested keyrings, where any
       keyring in the set has more than 16 keyrings and none of the
       first keyrings we look through has a match (before the tree
       iteration needs to step to a more distal node).

     Test in keyutils test suite:

        http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=8b4ae963ed92523aea18dfbb8cab3f4979e13bd1

   - A patch to fix the big_key type's use of a shmem file as its
     backing store causing audit messages and LSM check failures.  This
     is done by setting S_PRIVATE on the file to avoid LSM checks on the
     file (access to the shmem file goes through the keyctl() interface
     and so is gated by the LSM that way).

     This isn't normally a problem if a key is used by the context that
     generated it - and it's currently only used by libkrb5.

     Test in keyutils test suite:

        http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=d9a53cbab42c293962f2f78f7190253fc73bd32e

   - A patch to add a generated file to .gitignore.

   - A patch to fix the alignment of the system certificate data such
     that it it works on s390.  As I understand it, on the S390 arch,
     symbols must be 2-byte aligned because loading the address discards
     the least-significant bit"

* tag 'keys-devel-20131210' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  KEYS: correct alignment of system_certificate_list content in assembly file
  Ignore generated file kernel/x509_certificate_list
  security: shmem: implement kernel private shmem inodes
  KEYS: Fix searching of nested keyrings
  KEYS: Fix multiple key add into associative array
  KEYS: Fix the keyring hash function
  KEYS: Pre-clear struct key on allocation
2013-12-12 10:15:24 -08:00
Linus Torvalds
5cdec2d833 futex: move user address verification up to common code
When debugging the read-only hugepage case, I was confused by the fact
that get_futex_key() did an access_ok() only for the non-shared futex
case, since the user address checking really isn't in any way specific
to the private key handling.

Now, it turns out that the shared key handling does effectively do the
equivalent checks inside get_user_pages_fast() (it doesn't actually
check the address range on x86, but does check the page protections for
being a user page).  So it wasn't actually a bug, but the fact that we
treat the address differently for private and shared futexes threw me
for a loop.

Just move the check up, so that it gets done for both cases.  Also, use
the 'rw' parameter for the type, even if it doesn't actually matter any
more (it's a historical artifact of the old racy i386 "page faults from
kernel space don't check write protections").

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-12 09:53:51 -08:00
Linus Torvalds
f12d5bfceb futex: fix handling of read-only-mapped hugepages
The hugepage code had the exact same bug that regular pages had in
commit 7485d0d375 ("futexes: Remove rw parameter from
get_futex_key()").

The regular page case was fixed by commit 9ea71503a8 ("futex: Fix
regression with read only mappings"), but the transparent hugepage case
(added in a5b338f2b0: "thp: update futex compound knowledge") case
remained broken.

Found by Dave Jones and his trinity tool.

Reported-and-tested-by: Dave Jones <davej@fedoraproject.org>
Cc: stable@kernel.org # v2.6.38+
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-12 09:38:42 -08:00
Hendrik Brueckner
62226983da KEYS: correct alignment of system_certificate_list content in assembly file
Apart from data-type specific alignment constraints, there are also
architecture-specific alignment requirements.
For example, on s390 symbols must be on even addresses implying a 2-byte
alignment.  If the system_certificate_list_end symbol is on an odd address
and if this address is loaded, the least-significant bit is ignored.  As a
result, the load_system_certificate_list() fails to load the certificates
because of a wrong certificate length calculation.

To be safe, align system_certificate_list on an 8-byte boundary.  Also improve
the length calculation of the system_certificate_list content.  Introduce a
system_certificate_list_size (8-byte aligned because of unsigned long) variable
that stores the length.  Let the linker calculate this size by introducing
a start and end label for the certificate content.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-10 18:25:28 +00:00
Rusty Russell
7cfe5b3310 Ignore generated file kernel/x509_certificate_list
$ git status
# On branch pending-rebases
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#	kernel/x509_certificate_list
nothing added to commit but untracked files present (use "git add" to track)
$

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-10 18:21:34 +00:00
Khalid Aziz
4fc9bbf98f PCI: Disable Bus Master only on kexec reboot
Add a flag to tell the PCI subsystem that kernel is shutting down in
preparation to kexec a kernel.  Add code in PCI subsystem to use this flag
to clear Bus Master bit on PCI devices only in case of kexec reboot.

This fixes a power-off problem on Acer Aspire V5-573G and likely other
machines and avoids any other issues caused by clearing Bus Master bit on
PCI devices in normal shutdown path.  The problem was introduced by
b566a22c23 ("PCI: disable Bus Master on PCI device shutdown").

This patch is based on discussion at
http://marc.info/?l=linux-pci&m=138425645204355&w=2

Link: https://bugzilla.kernel.org/show_bug.cgi?id=63861
Reported-by: Chang Liu <cl91tp@gmail.com>
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: stable@vger.kernel.org	# v3.5+
2013-12-07 14:20:28 -07:00
Linus Torvalds
843f4f4bb1 Merge tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
 "A regression showed up that there's a large delay when enabling all
  events.  This was prevalent when FTRACE_SELFTEST was enabled which
  enables all events several times, and caused the system bootup to
  pause for over a minute.

  This was tracked down to an addition of a synchronize_sched()
  performed when system call tracepoints are unregistered.

  The synchronize_sched() is needed between the unregistering of the
  system call tracepoint and a deletion of a tracing instance buffer.
  But placing the synchronize_sched() in the unreg of *every* system
  call tracepoint is a bit overboard.  A single synchronize_sched()
  before the deletion of the instance is sufficient"

* tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Only run synchronize_sched() at instance deletion time
2013-12-06 08:34:16 -08:00
Steven Rostedt
3ccb012392 tracing: Only run synchronize_sched() at instance deletion time
It has been reported that boot up with FTRACE_SELFTEST enabled can take a
very long time. There can be stalls of over a minute.

This was tracked down to the synchronize_sched() called when a system call
event is disabled. As the self tests enable and disable thousands of events,
this makes the synchronize_sched() get called thousands of times.

The synchornize_sched() was added with d562aff93b "tracing: Add support
for SOFT_DISABLE to syscall events" which caused this regression (added
in 3.13-rc1).

The synchronize_sched() is to protect against the events being accessed
when a tracer instance is being deleted. When an instance is being deleted
all the events associated to it are unregistered. The synchronize_sched()
makes sure that no more users are running when it finishes.

Instead of calling synchronize_sched() for all syscall events, we only
need to call it once, after the events are unregistered and before the
instance is deleted. The event_mutex is held during this action to
prevent new users from enabling events.

Link: http://lkml.kernel.org/r/20131203124120.427b9661@gandalf.local.home

Reported-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-12-05 14:22:30 -05:00
Linus Torvalds
1ab231b274 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:

 - timekeeping: Cure a subtle drift issue on GENERIC_TIME_VSYSCALL_OLD

 - nohz: Make CONFIG_NO_HZ=n and nohz=off command line option behave the
   same way.  Fixes a long standing load accounting wreckage.

 - clocksource/ARM: Kconfig update to avoid ARM=n wreckage

 - clocksource/ARM: Fixlets for the AT91 and SH clocksource/clockevents

 - Trivial documentation update and kzalloc conversion from akpms pile

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off
  time: Fix 1ns/tick drift w/ GENERIC_TIME_VSYSCALL_OLD
  clocksource: arm_arch_timer: Hide eventstream Kconfig on non-ARM
  clocksource: sh_tmu: Add clk_prepare/unprepare support
  clocksource: sh_tmu: Release clock when sh_tmu_register() fails
  clocksource: sh_mtu2: Add clk_prepare/unprepare support
  clocksource: sh_mtu2: Release clock when sh_mtu2_register() fails
  ARM: at91: rm9200: switch back to clockevents_config_and_register
  tick: Document tick_do_timer_cpu
  timer: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...)
  NOHZ: Check for nohz active instead of nohz enabled
2013-12-04 08:52:09 -08:00
Linus Torvalds
a45299e727 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
 - Correction of fuzzy and fragile IRQ_RETVAL macro
 - IRQ related resume fix affecting only XEN
 - ARM/GIC fix for chained GIC controllers

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip: Gic: fix boot for chained gics
  irq: Enable all irqs unconditionally in irq_resume
  genirq: Correct fuzzy and fragile IRQ_RETVAL() definition
2013-12-02 10:15:39 -08:00
Linus Torvalds
a0b57ca33e Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Various smaller fixlets, all over the place"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/doc: Fix generation of device-drivers
  sched: Expose preempt_schedule_irq()
  sched: Fix a trivial typo in comments
  sched: Remove unused variable in 'struct sched_domain'
  sched: Avoid NULL dereference on sd_busy
  sched: Check sched_domain before computing group power
  MAINTAINERS: Update file patterns in the lockdep and scheduler entries
2013-12-02 10:13:44 -08:00
Linus Torvalds
e321ae4c20 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "Misc kernel and tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tools lib traceevent: Fix conversion of pointer to integer of different size
  perf/trace: Properly use u64 to hold event_id
  perf: Remove fragile swevent hlist optimization
  ftrace, perf: Avoid infinite event generation loop
  tools lib traceevent: Fix use of multiple options in processing field
  perf header: Fix possible memory leaks in process_group_desc()
  perf header: Fix bogus group name
  perf tools: Tag thread comm as overriden
2013-12-02 10:13:09 -08:00
Linus Torvalds
7224b31bd5 Merge branch 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fixes from Tejun Heo:
 "This contains one important fix.  The NUMA support added a while back
  broke ordering guarantees on ordered workqueues.  It was enforced by
  having single frontend interface with @max_active == 1 but the NUMA
  support puts multiple interfaces on unbound workqueues on NUMA
  machines thus breaking the ordered guarantee.  This is fixed by
  disabling NUMA support on ordered workqueues.

  The above and a couple other patches were sitting in for-3.12-fixes
  but I forgot to push that out, so they ended up waiting a bit too
  long.  My aplogies.

  Other fixes are minor"

* 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix pool ID allocation leakage and remove BUILD_BUG_ON() in init_workqueues
  workqueue: fix comment typo for __queue_work()
  workqueue: fix ordered workqueues in NUMA setups
  workqueue: swap set_cpus_allowed_ptr() and PF_NO_SETAFFINITY
2013-11-29 09:49:08 -08:00
Linus Torvalds
2855987d13 Merge branch 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "Fixes for three issues.

   - cgroup destruction path could swamp system_wq possibly leading to
     deadlock.  This actually seems to happen in the wild with memcg
     because memcg destruction path adds nested dependency on system_wq.

     Resolved by isolating cgroup destruction work items on its
     dedicated workqueue.

   - Possible locking context deadlock through seqcount reported by
     lockdep

   - Memory leak under certain conditions"

* 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix cgroup_subsys_state leak for seq_files
  cpuset: Fix memory allocator deadlock
  cgroup: use a dedicated workqueue for cgroup destruction
2013-11-29 09:47:06 -08:00
Thomas Gleixner
0e576acbc1 nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off
If CONFIG_NO_HZ=n tick_nohz_get_sleep_length() returns NSEC_PER_SEC/HZ.

If CONFIG_NO_HZ=y and the nohz functionality is disabled via the
command line option "nohz=off" or not enabled due to missing hardware
support, then tick_nohz_get_sleep_length() returns 0. That happens
because ts->sleep_length is never set in that case.

Set it to NSEC_PER_SEC/HZ when the NOHZ mode is inactive.

Reported-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-11-29 12:23:03 +01:00
Helge Deller
5ecbe3c3c6 kernel/extable: fix address-checks for core_kernel and init areas
The init_kernel_text() and core_kernel_text() functions should not
include the labels _einittext and _etext when checking if an address is
inside the .text or .init sections.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-28 09:49:41 -08:00
Tejun Heo
e605b36575 cgroup: fix cgroup_subsys_state leak for seq_files
If a cgroup file implements either read_map() or read_seq_string(),
such file is served using seq_file by overriding file->f_op to
cgroup_seqfile_operations, which also overrides the release method to
single_release() from cgroup_file_release().

Because cgroup_file_open() didn't use to acquire any resources, this
used to be fine, but since f7d58818ba ("cgroup: pin
cgroup_subsys_state when opening a cgroupfs file"), cgroup_file_open()
pins the css (cgroup_subsys_state) which is put by
cgroup_file_release().  The patch forgot to update the release path
for seq_files and each open/release cycle leaks a css reference.

Fix it by updating cgroup_file_release() to also handle seq_files and
using it for seq_file release path too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v3.12
2013-11-27 18:16:21 -05:00
Peter Zijlstra
0fc0287c9e cpuset: Fix memory allocator deadlock
Juri hit the below lockdep report:

[    4.303391] ======================================================
[    4.303392] [ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]
[    4.303394] 3.12.0-dl-peterz+ #144 Not tainted
[    4.303395] ------------------------------------------------------
[    4.303397] kworker/u4:3/689 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
[    4.303399]  (&p->mems_allowed_seq){+.+...}, at: [<ffffffff8114e63c>] new_slab+0x6c/0x290
[    4.303417]
[    4.303417] and this task is already holding:
[    4.303418]  (&(&q->__queue_lock)->rlock){..-...}, at: [<ffffffff812d2dfb>] blk_execute_rq_nowait+0x5b/0x100
[    4.303431] which would create a new lock dependency:
[    4.303432]  (&(&q->__queue_lock)->rlock){..-...} -> (&p->mems_allowed_seq){+.+...}
[    4.303436]

[    4.303898] the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock:
[    4.303918] -> (&p->mems_allowed_seq){+.+...} ops: 2762 {
[    4.303922]    HARDIRQ-ON-W at:
[    4.303923]                     [<ffffffff8108ab9a>] __lock_acquire+0x65a/0x1ff0
[    4.303926]                     [<ffffffff8108cbe3>] lock_acquire+0x93/0x140
[    4.303929]                     [<ffffffff81063dd6>] kthreadd+0x86/0x180
[    4.303931]                     [<ffffffff816ded6c>] ret_from_fork+0x7c/0xb0
[    4.303933]    SOFTIRQ-ON-W at:
[    4.303933]                     [<ffffffff8108abcc>] __lock_acquire+0x68c/0x1ff0
[    4.303935]                     [<ffffffff8108cbe3>] lock_acquire+0x93/0x140
[    4.303940]                     [<ffffffff81063dd6>] kthreadd+0x86/0x180
[    4.303955]                     [<ffffffff816ded6c>] ret_from_fork+0x7c/0xb0
[    4.303959]    INITIAL USE at:
[    4.303960]                    [<ffffffff8108a884>] __lock_acquire+0x344/0x1ff0
[    4.303963]                    [<ffffffff8108cbe3>] lock_acquire+0x93/0x140
[    4.303966]                    [<ffffffff81063dd6>] kthreadd+0x86/0x180
[    4.303969]                    [<ffffffff816ded6c>] ret_from_fork+0x7c/0xb0
[    4.303972]  }

Which reports that we take mems_allowed_seq with interrupts enabled. A
little digging found that this can only be from
cpuset_change_task_nodemask().

This is an actual deadlock because an interrupt doing an allocation will
hit get_mems_allowed()->...->__read_seqcount_begin(), which will spin
forever waiting for the write side to complete.

Cc: John Stultz <john.stultz@linaro.org>
Cc: Mel Gorman <mgorman@suse.de>
Reported-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Juri Lelli <juri.lelli@gmail.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
2013-11-27 13:52:47 -05:00
Sasha Levin
8dce7a9a6f lockdep: Be nice about building from userspace
Lockdep is an awesome piece of code which detects locking issues
which are relevant both to userspace and kernelspace. We can
easily make lockdep work in userspace since there is really no
kernel spacific magic going on in the code.

All we need is to wrap two functions which are used by lockdep
and are very kernel specific.

Doing that will allow tools located in tools/ to easily utilize
lockdep's code for their own use.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: penberg@kernel.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1352753446-24109-1-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-27 11:55:20 +01:00
Frederic Weisbecker
5c4853b60c lockdep: Simplify a bit hardirq <-> softirq transitions
Instead of saving the hardirq state on a per CPU variable, which require
an explicit call before the softirq handling and some complication,
just save and restore the hardirq tracing state through functions
return values and parameters.

It simplifies a bit the black magic that works around the fact that
softirqs can be called from hardirqs while hardirqs can nest on softirqs
but those two cases have very different semantics and only the latter
case assume both states.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1384906054-30676-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-27 11:09:40 +01:00
Ingo Molnar
7d5b158310 Merge branch 'core/urgent' into core/locking
Prepare for dependent patch.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-27 11:09:19 +01:00
Thomas Gleixner
32e475d76a sched: Expose preempt_schedule_irq()
Tony reported that aa0d532605 ("ia64: Use preempt_schedule_irq")
broke PREEMPT=n builds on ia64.

Ok, wrapped my brain around it. I tripped over the magic asm foo which
has a single need_resched check and schedule point for both sys call
return and interrupt return.

So you need the schedule_preempt_irq() for kernel preemption from
interrupt return while on a normal syscall preemption a schedule would
be sufficient. But using schedule_preempt_irq() is not harmful here in
any way. It just sets the preempt_active bit also in cases where it
would not be required.

Even on preempt=n kernels adding the preempt_active bit is completely
harmless. So instead of having an extra function, moving the existing
one out of the ifdef PREEMPT looks like the sanest thing to do.

It would also allow getting rid of various other sti/schedule/cli asm
magic in other archs.

Reported-and-Tested-by: Tony Luck <tony.luck@gmail.com>
Fixes: aa0d532605 ("ia64: Use preempt_schedule_irq")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[slightly edited Changelog]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311211230030.30673@ionos.tec.linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-27 11:04:53 +01:00