clear_freeze_flag() in exit_mm() is racy. Freezing can start
afterwards. Remove it. Skipping freezer for exiting task will be
properly implemented later.
Also, freezable() was testing exit_state directly to make system
freezer ignore dead tasks. Let the exiting task set PF_NOFREEZE after
entering TASK_DEAD instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
thaw_process() now has only internal users - system and cgroup
freezers. Remove the unnecessary return value, rename, unexport and
collapse __thaw_process() into it. This will help further updates to
the freezer code.
-v3: oom_kill grew a use of thaw_process() while this patch was
pending. Convert it to use __thaw_task() for now. In the longer
term, this should be handled by allowing tasks to die if killed
even if it's frozen.
-v2: minor style update as suggested by Matt.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Menage <menage@google.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Writeback and thinkpad_acpi have been using thaw_process() to prevent
deadlock between the freezer and kthread_stop(); unfortunately, this
is inherently racy - nothing prevents freezing from happening between
thaw_process() and kthread_stop().
This patch implements kthread_freezable_should_stop() which enters
refrigerator if necessary but is guaranteed to return if
kthread_stop() is invoked. Both thaw_process() users are converted to
use the new function.
Note that this deadlock condition exists for many of freezable
kthreads. They need to be converted to use the new should_stop or
freezable workqueue.
Tested with synthetic test case.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
There is no reason to export two functions for entering the
refrigerator. Calling refrigerator() instead of try_to_freeze()
doesn't save anything noticeable or removes any race condition.
* Rename refrigerator() to __refrigerator() and make it return bool
indicating whether it scheduled out for freezing.
* Update try_to_freeze() to return bool and relay the return value of
__refrigerator() if freezing().
* Convert all refrigerator() users to try_to_freeze().
* Update documentation accordingly.
* While at it, add might_sleep() to try_to_freeze().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Some drivers set PF_NOFREEZE in their kthread functions which is
completely unnecessary and racy - some part of freezer code doesn't
consider cases where PF_NOFREEZE is set asynchronous to freezer
operations.
In general, there's no reason to allow setting PF_NOFREEZE explicitly.
Remove them and change the documentation to note that setting
PF_NOFREEZE directly isn't allowed.
-v2: Dropped change to twl4030-irq.c as it no longer uses PF_NOFREEZE.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: "Gustavo F. Padovan" <padovan@profusion.mobi>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: wwang <wei_wang@realsil.com.cn>
refrigerator() saves current->state before entering frozen state and
restores it before returning using __set_current_state(); however,
this is racy, for example, please consider the following sequence.
set_current_state(TASK_INTERRUPTIBLE);
try_to_freeze();
if (kthread_should_stop())
break;
schedule();
If kthread_stop() races with ->state restoration, the restoration can
restore ->state to TASK_INTERRUPTIBLE after kthread_stop() sets it to
TASK_RUNNING but kthread_should_stop() may still see zero
->should_stop because there's no memory barrier between restoring
TASK_INTERRUPTIBLE and kthread_should_stop() test.
This isn't restricted to kthread_should_stop(). current->state is
often used in memory barrier based synchronization and silently
restoring it w/o mb breaks them.
Use set_current_state() instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (86 commits)
ipv4: fix redirect handling
ping: dont increment ICMP_MIB_INERRORS
sky2: fix hang in napi_disable
sky2: enforce minimum ring size
bonding: Don't allow mode change via sysfs with slaves present
f_phonet: fix page offset of first received fragment
stmmac: fix pm functions avoiding sleep on spinlock
stmmac: remove spin_lock in stmmac_ioctl.
stmmac: parameters auto-tuning through HW cap reg
stmmac: fix advertising 1000Base capabilties for non GMII iface
stmmac: use mdelay on timeout of sw reset
sky2: version 1.30
sky2: used fixed RSS key
sky2: reduce default Tx ring size
sky2: rename up/down functions
sky2: pci posting issues
sky2: fix hang on shutdown (and other irq issues)
r6040: fix check against MCRO_HASHEN bit in r6040_multicast_list
MAINTAINERS: change email address for shemminger
pch_gbe: Move #include of module.h
...
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM / Suspend: Fix bug in suspend statistics update
PM / Hibernate: Fix the early termination of test modes
PM / shmobile: Fix build of sh7372_pm_init() for CONFIG_PM unset
PM Sleep: Do not extend wakeup paths to devices with ignore_children set
PM / driver core: disable device's runtime PM during shutdown
PM / devfreq: correct Kconfig dependency
PM / devfreq: fix use after free in devfreq_remove_device
PM / shmobile: Avoid restoring the INTCS state during initialization
PM / devfreq: Remove compiler error after irq.h update
PM / QoS: Properly use the WARN() macro in dev_pm_qos_add_request()
PM / Clocks: Only disable enabled clocks in pm_clk_suspend()
ARM: mach-shmobile: sh7372 A3SP no_suspend_console fix
PM / shmobile: Don't skip debugging output in pd_power_up()
Prevent tracing of preempt_disable() in get_cpu_var() in
kvm_clock_read(). When CONFIG_DEBUG_PREEMPT is enabled,
preempt_disable/enable() are traced and this causes the function_graph
tracer to go into an infinite recursion. By open coding the
preempt_disable() around the get_cpu_var(), we can use the notrace
version which prevents preempt_disable/enable() from being traced and
prevents the recursion.
Based on a similar patch for Xen from Jeremy Fitzhardinge.
Tested-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: (exynos4_tmu) Fix Kconfig dependency
[ Merging code in-flight, just because I can. What timezone should I
use? - Linus ]
After commit 2a77c46de1
(PM / Suspend: Add statistics debugfs file for suspend to RAM)
a missing pair of braces inside the state_store() function causes even
invalid arguments to suspend to be wrongly treated as failed suspend
attempts. Fix this.
[rjw: Put the hash/subject of the buggy commit into the changelog.]
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Dummy, non-zero definitions for HPAGE_MASK and HPAGE_SIZE were added in
51c6f666fc ("mm: ZAP_BLOCK causes redundant work") to avoid a divide
by zero in generic kernel code.
That code has since been removed, but probably should never have been
added in the first place: we don't want HPAGE_SIZE to act like PAGE_SIZE
for code that is working with hugepages, for example, when the
dependency on CONFIG_HUGETLB_PAGE has not been fulfilled.
Because hugepage size can differ from architecture to architecture, each
is required to have their own definitions for both HPAGE_MASK and
HPAGE_SIZE. This is always done in arch/*/include/asm/page.h.
So, just remove the dummy and dangerous definitions since they are no
longer needed and reveals the correct dependencies. Tested on
architectures using the definitions with allyesconfig: x86 (even with
thp), hppa, mips, powerpc, s390, sh3, sh4, sparc, and sparc64, and with
defconfig on ia64.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
new helper: mount_subtree()
switch create_mnt_ns() to saner calling conventions, fix double mntput() in nfs
btrfs: fix double mntput() in mount_subvol()
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
random: Fix handing of arch_get_random_long in get_random_bytes()
x86: Call stop_machine_text_poke() on all CPUs
x86, ioapic: Only print ioapic debug information for IRQs belonging to an ioapic chip
x86/mrst: Avoid reporting wrong nmi status
x86/mrst: Add support for Penwell clock calibration
x86/apic: Allow use of lapic timer early calibration result
x86/apic: Do not clear nr_irqs_gsi if no legacy irqs
x86/platform: Add a wallclock_init func to x86_platforms ops
x86/mce: Make mce_chrdev_ops 'static const'
As is probably painfully obvious, I don't have time to be a cgroups
maintainer. Rather than have me continue to hope that I'll magically
find more spare time, instead Tejun has kindly agreed to take over the
role, along with Li Zefan.
-tj: added cgroup tree URL to MAINTAINERS file
Signed-off-by: Paul Menage <paul@paulmenage.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <1321320612-57855-1-git-send-email-paul@paulmenage.org>
Commit 2aede851dd
(PM / Hibernate: Freeze kernel threads after preallocating memory)
postponed the freezing of kernel threads to after preallocating memory
for hibernation. But while doing that, the hibernation test TEST_FREEZER
and the test mode HIBERNATION_TESTPROC were not moved accordingly.
As a result, when using these test modes, it only goes upto the freezing of
userspace and exits, when in fact it should go till the complete end of task
freezing stage, namely the freezing of kernel threads as well.
So, move these points of exit to appropriate places so that freezing of
kernel threads is also tested while using these test harnesses.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
commit f39925dbde (ipv4: Cache learned redirect information in
inetpeer.) introduced a regression in ICMP redirect handling.
It assumed ipv4_dst_check() would be called because all possible routes
were attached to the inetpeer we modify in ip_rt_redirect(), but thats
not true.
commit 7cc9150ebe (route: fix ICMP redirect validation) tried to fix
this but solution was not complete. (It fixed only one route)
So we must lookup existing routes (including different TOS values) and
call check_peer_redir() on them.
Reported-by: Ivan Zahariev <famzah@icdsoft.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I will no longer be maintaining XFS for SGI. Ben Myers
(bpm@sgi.com) has agreed to be the primary maintainer
for XFS in my place. I will continue to be able to push
commits to the SGI XFS tree if required. As such I will
continue to be a designated XFS maintainer, but plan to
serve in more of a backup role.
Signed-off-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Tejun Heo
Linus Torvalds
Avi Kivity
Srivatsa S. Bhat
Jeremy Fitzhardinge
David Rientjes
Paul Menage
Eric Dumazet
Alex Elder