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2014-12-13syscalls: implement execveat() system callDavid Drysdale1-0/+4
This patchset adds execveat(2) for x86, and is derived from Meredydd Luff's patch from Sept 2012 (https://lkml.org/lkml/2012/9/11/528). The primary aim of adding an execveat syscall is to allow an implementation of fexecve(3) that does not rely on the /proc filesystem, at least for executables (rather than scripts). The current glibc version of fexecve(3) is implemented via /proc, which causes problems in sandboxed or otherwise restricted environments. Given the desire for a /proc-free fexecve() implementation, HPA suggested (https://lkml.org/lkml/2006/7/11/556) that an execveat(2) syscall would be an appropriate generalization. Also, having a new syscall means that it can take a flags argument without back-compatibility concerns. The current implementation just defines the AT_EMPTY_PATH and AT_SYMLINK_NOFOLLOW flags, but other flags could be added in future -- for example, flags for new namespaces (as suggested at https://lkml.org/lkml/2006/7/11/474). Related history: - https://lkml.org/lkml/2006/12/27/123 is an example of someone realizing that fexecve() is likely to fail in a chroot environment. - http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=514043 covered documenting the /proc requirement of fexecve(3) in its manpage, to "prevent other people from wasting their time". - https://bugzilla.redhat.com/show_bug.cgi?id=241609 described a problem where a process that did setuid() could not fexecve() because it no longer had access to /proc/self/fd; this has since been fixed. This patch (of 4): Add a new execveat(2) system call. execveat() is to execve() as openat() is to open(): it takes a file descriptor that refers to a directory, and resolves the filename relative to that. In addition, if the filename is empty and AT_EMPTY_PATH is specified, execveat() executes the file to which the file descriptor refers. This replicates the functionality of fexecve(), which is a system call in other UNIXen, but in Linux glibc it depends on opening "/proc/self/fd/<fd>" (and so relies on /proc being mounted). The filename fed to the executed program as argv[0] (or the name of the script fed to a script interpreter) will be of the form "/dev/fd/<fd>" (for an empty filename) or "/dev/fd/<fd>/<filename>", effectively reflecting how the executable was found. This does however mean that execution of a script in a /proc-less environment won't work; also, script execution via an O_CLOEXEC file descriptor fails (as the file will not be accessible after exec). Based on patches by Meredydd Luff. Signed-off-by: David Drysdale <drysdale@google.com> Cc: Meredydd Luff <meredydd@senatehouse.org> Cc: Shuah Khan <shuah.kh@samsung.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rich Felker <dalias@aerifal.cx> Cc: Christoph Hellwig <hch@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13memcg: turn memcg_kmem_skip_account into a bit fieldVladimir Davydov1-2/+5
It isn't supposed to stack, so turn it into a bit-field to save 4 bytes on the task_struct. Also, remove the memcg_stop/resume_kmem_account helpers - it is clearer to set/clear the flag inline. Regarding the overwhelming comment to the helpers, which is removed by this patch too, we already have a compact yet accurate explanation in memcg_schedule_cache_create, no need in yet another one. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10Merge branch 'sched-core-for-linus' of ↵Linus Torvalds1-23/+64
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this cycle are: - 'Nested Sleep Debugging', activated when CONFIG_DEBUG_ATOMIC_SLEEP=y. This instruments might_sleep() checks to catch places that nest blocking primitives - such as mutex usage in a wait loop. Such bugs can result in hard to debug races/hangs. Another category of invalid nesting that this facility will detect is the calling of blocking functions from within schedule() -> sched_submit_work() -> blk_schedule_flush_plug(). There's some potential for false positives (if secondary blocking primitives themselves are not ready yet for this facility), but the kernel will warn once about such bugs per bootup, so the warning isn't much of a nuisance. This feature comes with a number of fixes, for problems uncovered with it, so no messages are expected normally. - Another round of sched/numa optimizations and refinements, for CONFIG_NUMA_BALANCING=y. - Another round of sched/dl fixes and refinements. Plus various smaller fixes and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits) sched: Add missing rcu protection to wake_up_all_idle_cpus sched/deadline: Introduce start_hrtick_dl() for !CONFIG_SCHED_HRTICK sched/numa: Init numa balancing fields of init_task sched/deadline: Remove unnecessary definitions in cpudeadline.h sched/cpupri: Remove unnecessary definitions in cpupri.h sched/deadline: Fix rq->dl.pushable_tasks bug in push_dl_task() sched/fair: Fix stale overloaded status in the busiest group finding logic sched: Move p->nr_cpus_allowed check to select_task_rq() sched/completion: Document when to use wait_for_completion_io_*() sched: Update comments about CLONE_NEWUTS and CLONE_NEWIPC sched/fair: Kill task_struct::numa_entry and numa_group::task_list sched: Refactor task_struct to use numa_faults instead of numa_* pointers sched/deadline: Don't check CONFIG_SMP in switched_from_dl() sched/deadline: Reschedule from switched_from_dl() after a successful pull sched/deadline: Push task away if the deadline is equal to curr during wakeup sched/deadline: Add deadline rq status print sched/deadline: Fix artificial overrun introduced by yield_task_dl() sched/rt: Clean up check_preempt_equal_prio() sched/core: Use dl_bw_of() under rcu_read_lock_sched() sched: Check if we got a shallowest_idle_cpu before searching for least_loaded_cpu ...
2014-11-04sched: Refactor task_struct to use numa_faults instead of numa_* pointersIulia Manda1-18/+13
This patch simplifies task_struct by removing the four numa_* pointers in the same array and replacing them with the array pointer. By doing this, on x86_64, the size of task_struct is reduced by 3 ulong pointers (24 bytes on x86_64). A new parameter is added to the task_faults_idx function so that it can return an index to the correct offset, corresponding with the old precalculated pointers. All of the code in sched/ that depended on task_faults_idx and numa_* was changed in order to match the new logic. Signed-off-by: Iulia Manda <iulia.manda21@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: mgorman@suse.de Cc: dave@stgolabs.net Cc: riel@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20141031001331.GA30662@winterfell Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-29rcu: Remove redundant TREE_PREEMPT_RCU config optionPranith Kumar1-2/+2
PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU has been removed. This patch removes TREE_PREEMPT_RCU and uses PREEMPT_RCU config option in its place. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-10-28sched: Exclude cond_resched() from nested sleep testPeter Zijlstra1-3/+3
cond_resched() is a preemption point, not strictly a blocking primitive, so exclude it from the ->state test. In particular, preemption preserves task_struct::state. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: tglx@linutronix.de Cc: ilya.dryomov@inktank.com Cc: umgwanakikbuti@gmail.com Cc: oleg@redhat.com Cc: Alex Elder <alex.elder@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Axel Lin <axel.lin@ingics.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Dave Jones <davej@redhat.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20140924082242.656559952@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-28sched: Debug nested sleepsPeter Zijlstra1-2/+44
Validate we call might_sleep() with TASK_RUNNING, which catches places where we nest blocking primitives, eg. mutex usage in a wait loop. Since all blocking is arranged through task_struct::state, nesting this will cause the inner primitive to set TASK_RUNNING and the outer will thus not block. Another observed problem is calling a blocking function from schedule()->sched_submit_work()->blk_schedule_flush_plug() which will then destroy the task state for the actual __schedule() call that comes after it. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: tglx@linutronix.de Cc: ilya.dryomov@inktank.com Cc: umgwanakikbuti@gmail.com Cc: oleg@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140924082242.591637616@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-28sched/deadline: Ensure that updates to exclusive cpusets don't break ACJuri Lelli1-0/+2
How we deal with updates to exclusive cpusets is currently broken. As an example, suppose we have an exclusive cpuset composed of two cpus: A[cpu0,cpu1]. We can assign SCHED_DEADLINE task to it up to the allowed bandwidth. If we want now to modify cpusetA's cpumask, we have to check that removing a cpu's amount of bandwidth doesn't break AC guarantees. This thing isn't checked in the current code. This patch fixes the problem above, denying an update if the new cpumask won't have enough bandwidth for SCHED_DEADLINE tasks that are currently active. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Li Zefan <lizefan@huawei.com> Cc: cgroups@vger.kernel.org Link: http://lkml.kernel.org/r/5433E6AF.5080105@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-28sched/deadline: Fix bandwidth check/update when migrating tasks between ↵Juri Lelli1-0/+2
exclusive cpusets Exclusive cpusets are the only way users can restrict SCHED_DEADLINE tasks affinity (performing what is commonly called clustered scheduling). Unfortunately, such thing is currently broken for two reasons: - No check is performed when the user tries to attach a task to an exlusive cpuset (recall that exclusive cpusets have an associated maximum allowed bandwidth). - Bandwidths of source and destination cpusets are not correctly updated after a task is migrated between them. This patch fixes both things at once, as they are opposite faces of the same coin. The check is performed in cpuset_can_attach(), as there aren't any points of failure after that function. The updated is split in two halves. We first reserve bandwidth in the destination cpuset, after we pass the check in cpuset_can_attach(). And we then release bandwidth from the source cpuset when the task's affinity is actually changed. Even if there can be time windows when sched_setattr() may erroneously fail in the source cpuset, we are fine with it, as we can't perfom an atomic update of both cpusets at once. Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Reported-by: Vincent Legout <vincent@legout.info> Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Michael Trimarchi <michael@amarulasolutions.com> Cc: Fabio Checconi <fchecconi@gmail.com> Cc: michael@amarulasolutions.com Cc: luca.abeni@unitn.it Cc: Li Zefan <lizefan@huawei.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: cgroups@vger.kernel.org Link: http://lkml.kernel.org/r/1411118561-26323-3-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-13Merge branch 'sched-core-for-linus' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave Hansen) - Various sched/idle refinements for better idle handling (Nicolas Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot) - sched/numa updates and optimizations (Rik van Riel) - sysbench speedup (Vincent Guittot) - capacity calculation cleanups/refactoring (Vincent Guittot) - Various cleanups to thread group iteration (Oleg Nesterov) - Double-rq-lock removal optimization and various refactorings (Kirill Tkhai) - various sched/deadline fixes ... and lots of other changes" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits) sched/dl: Use dl_bw_of() under rcu_read_lock_sched() sched/fair: Delete resched_cpu() from idle_balance() sched, time: Fix build error with 64 bit cputime_t on 32 bit systems sched: Improve sysbench performance by fixing spurious active migration sched/x86: Fix up typo in topology detection x86, sched: Add new topology for multi-NUMA-node CPUs sched/rt: Use resched_curr() in task_tick_rt() sched: Use rq->rd in sched_setaffinity() under RCU read lock sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask' sched: Use dl_bw_of() under RCU read lock sched/fair: Remove duplicate code from can_migrate_task() sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW sched: print_rq(): Don't use tasklist_lock sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock() sched: Fix the task-group check in tg_has_rt_tasks() sched/fair: Leverage the idle state info when choosing the "idlest" cpu sched: Let the scheduler see CPU idle states sched/deadline: Fix inter- exclusive cpusets migrations sched/deadline: Clear dl_entity params when setscheduling to different class sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault() ...
2014-10-13Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds1-17/+22
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes in this cycle were: - changes related to No-CBs CPUs and NO_HZ_FULL - RCU-tasks implementation - torture-test updates - miscellaneous fixes - locktorture updates - RCU documentation updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits) workqueue: Use cond_resched_rcu_qs macro workqueue: Add quiescent state between work items locktorture: Cleanup header usage locktorture: Cannot hold read and write lock locktorture: Fix __acquire annotation for spinlock irq locktorture: Support rwlocks rcu: Eliminate deadlock between CPU hotplug and expedited grace periods locktorture: Document boot/module parameters rcutorture: Rename rcutorture_runnable parameter locktorture: Add test scenario for rwsem_lock locktorture: Add test scenario for mutex_lock locktorture: Make torture scripting account for new _runnable name locktorture: Introduce torture context locktorture: Support rwsems locktorture: Add infrastructure for torturing read locks torture: Address race in module cleanup locktorture: Make statistics generic locktorture: Teach about lock debugging locktorture: Support mutexes locktorture: Add documentation ...
2014-10-10mm: clear __GFP_FS when PF_MEMALLOC_NOIO is setJunxiao Bi1-2/+4
commit 21caf2fc1931 ("mm: teach mm by current context info to not do I/O during memory allocation") introduces PF_MEMALLOC_NOIO flag to avoid doing I/O inside memory allocation, __GFP_IO is cleared when this flag is set, but __GFP_FS implies __GFP_IO, it should also be cleared. Or it may still run into I/O, like in superblock shrinker. And this will make the kernel run into the deadlock case described in that commit. See Dave Chinner's comment about io in superblock shrinker: Filesystem shrinkers do indeed perform IO from the superblock shrinker and have for years. Even clean inodes can require IO before they can be freed - e.g. on an orphan list, need truncation of post-eof blocks, need to wait for ordered operations to complete before it can be freed, etc. IOWs, Ext4, btrfs and XFS all can issue and/or block on arbitrary amounts of IO in the superblock shrinker context. XFS, in particular, has been doing transactions and IO from the VFS inode cache shrinker since it was first introduced.... Fix this by clearing __GFP_FS in memalloc_noio_flags(), this function has masked all the gfp_mask that will be passed into fs for the processes setting PF_MEMALLOC_NOIO in the direct reclaim path. v1 thread at: https://lkml.org/lkml/2014/9/3/32 Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: joyce.xue <xuejiufei@huawei.com> Cc: Ming Lei <ming.lei@canonical.com> Cc: Trond Myklebust <trond.myklebust@primarydata.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds1-0/+1
Pull crypto update from Herbert Xu: - add multibuffer infrastructure (single_task_running scheduler helper, OKed by Peter on lkml. - add SHA1 multibuffer implementation for AVX2. - reenable "by8" AVX CTR optimisation after fixing counter overflow. - add APM X-Gene SoC RNG support. - SHA256/SHA512 now handles unaligned input correctly. - set lz4 decompressed length correctly. - fix algif socket buffer allocation failure for 64K page machines. - misc fixes * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (47 commits) crypto: sha - Handle unaligned input data in generic sha256 and sha512. Revert "crypto: aesni - disable "by8" AVX CTR optimization" crypto: aesni - remove unused defines in "by8" variant crypto: aesni - fix counter overflow handling in "by8" variant hwrng: printk replacement crypto: qat - Removed unneeded partial state crypto: qat - Fix typo in name of tasklet_struct crypto: caam - Dynamic allocation of addresses for various memory blocks in CAAM. crypto: mcryptd - Fix typos in CRYPTO_MCRYPTD description crypto: algif - avoid excessive use of socket buffer in skcipher arm64: dts: add random number generator dts node to APM X-Gene platform. Documentation: rng: Add X-Gene SoC RNG driver documentation hwrng: xgene - add support for APM X-Gene SoC RNG support crypto: mv_cesa - Add missing #define crypto: testmgr - add test for lz4 and lz4hc crypto: lz4,lz4hc - fix decompression crypto: qat - Use pci_enable_msix_exact() instead of pci_enable_msix() crypto: drbg - fix maximum value checks on 32 bit systems crypto: drbg - fix sparse warning for cpu_to_be[32|64] crypto: sha-mb - sha1_mb_alg_state can be static ...
2014-09-28Merge branch 'for-3.17-fixes' of ↵Linus Torvalds1-13/+25
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "This is quite late but these need to be backported anyway. This is the fix for a long-standing cpuset bug which existed from 2009. cpuset makes use of PF_SPREAD_{PAGE|SLAB} flags to modify the task's memory allocation behavior according to the settings of the cpuset it belongs to; unfortunately, when those flags have to be changed, cpuset did so directly even whlie the target task is running, which is obviously racy as task->flags may be modified by the task itself at any time. This obscure bug manifested as corrupt PF_USED_MATH flag leading to a weird crash. The bug is fixed by moving the flag to task->atomic_flags. The first two are prepatory ones to help defining atomic_flags accessors and the third one is the actual fix" * 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags sched: add macros to define bitops for task atomic flags sched: fix confusing PFA_NO_NEW_PRIVS constant
2014-09-25cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flagsZefan Li1-2/+11
When we change cpuset.memory_spread_{page,slab}, cpuset will flip PF_SPREAD_{PAGE,SLAB} bit of tsk->flags for each task in that cpuset. This should be done using atomic bitops, but currently we don't, which is broken. Tetsuo reported a hard-to-reproduce kernel crash on RHEL6, which happened when one thread tried to clear PF_USED_MATH while at the same time another thread tried to flip PF_SPREAD_PAGE/PF_SPREAD_SLAB. They both operate on the same task. Here's the full report: https://lkml.org/lkml/2014/9/19/230 To fix this, we make PF_SPREAD_PAGE and PF_SPREAD_SLAB atomic flags. v4: - updated mm/slab.c. (Fengguang Wu) - updated Documentation. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Miao Xie <miaox@cn.fujitsu.com> Cc: Kees Cook <keescook@chromium.org> Fixes: 950592f7b991 ("cpusets: update tasks' page/slab spread flags in time") Cc: <stable@vger.kernel.org> # 2.6.31+ Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-09-25sched: add macros to define bitops for task atomic flagsZefan Li1-9/+12
This will simplify code when we add new flags. v3: - Kees pointed out that no_new_privs should never be cleared, so we shouldn't define task_clear_no_new_privs(). we define 3 macros instead of a single one. v2: - updated scripts/tags.sh, suggested by Peter Cc: Ingo Molnar <mingo@kernel.org> Cc: Miao Xie <miaox@cn.fujitsu.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-09-25sched: fix confusing PFA_NO_NEW_PRIVS constantZefan Li1-1/+1
Commit 1d4457f99928 ("sched: move no_new_privs into new atomic flags") defined PFA_NO_NEW_PRIVS as hexadecimal value, but it is confusing because it is used as bit number. Redefine it as decimal bit number. Note this changes the bit position of PFA_NOW_NEW_PRIVS from 1 to 0. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Kees Cook <keescook@chromium.org> [ lizf: slightly modified subject and changelog ] Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-09-20sched: Fix end_of_stack() and location of stack canary for architectures ↵Chuck Ebbert1-0/+13
using CONFIG_STACK_GROWSUP Aaron Tomlin recently posted patches [1] to enable checking the stack canary on every task switch. Looking at the canary code, I realized that every arch (except ia64, which adds some space for register spill above the stack) shares a definition of end_of_stack() that makes it the first long after the threadinfo. For stacks that grow down, this low address is correct because the stack starts at the end of the thread area and grows toward lower addresses. However, for stacks that grow up, toward higher addresses, this is wrong. (The stack actually grows away from the canary.) On these archs end_of_stack() should return the address of the last long, at the highest possible address for the stack. [1] http://lkml.org/lkml/2014/9/12/293 Signed-off-by: Chuck Ebbert <cebbert.lkml@gmail.com> Link: http://lkml.kernel.org/r/20140920101751.6c5166b6@as Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: James Hogan <james.hogan@imgtec.com> [metag] Acked-by: James Hogan <james.hogan@imgtec.com> Acked-by: Aaron Tomlin <atomlin@redhat.com>
2014-09-19sched: Add helper for task stack page overrun checkingAaron Tomlin1-0/+2
This facility is used in a few places so let's introduce a helper function to improve code readability. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: oleg@redhat.com Cc: riel@redhat.com Cc: prarit@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19init/main.c: Give init_task a canaryAaron Tomlin1-0/+2
Tasks get their end of stack set to STACK_END_MAGIC with the aim to catch stack overruns. Currently this feature does not apply to init_task. This patch removes this restriction. Note that a similar patch was posted by Prarit Bhargava some time ago but was never merged: http://marc.info/?l=linux-kernel&m=127144305403241&w=2 Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19sched: Add new API wake_up_if_idle() to wake up the idle cpuChuansheng Liu1-0/+1
Implementing one new API wake_up_if_idle(), which is used to wake up the idle CPU. Suggested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: daniel.lezcano@linaro.org Cc: rjw@rjwysocki.net Cc: linux-pm@vger.kernel.org Cc: changcheng.liu@intel.com Cc: xiaoming.wang@intel.com Cc: souvik.k.chakravarty@intel.com Cc: chuansheng.liu@intel.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409815075-4180-1-git-send-email-chuansheng.liu@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-08time, signal: Protect resource use statistics with seqlockRik van Riel1-0/+1
Both times() and clock_gettime(CLOCK_PROCESS_CPUTIME_ID) have scalability issues on large systems, due to both functions being serialized with a lock. The lock protects against reporting a wrong value, due to a thread in the task group exiting, its statistics reporting up to the signal struct, and that exited task's statistics being counted twice (or not at all). Protecting that with a lock results in times() and clock_gettime() being completely serialized on large systems. This can be fixed by using a seqlock around the events that gather and propagate statistics. As an additional benefit, the protection code can be moved into thread_group_cputime(), slightly simplifying the calling functions. In the case of posix_cpu_clock_get_task() things can be simplified a lot, because the calling function already ensures that the task sticks around, and the rest is now taken care of in thread_group_cputime(). This way the statistics reporting code can run lockless. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guillaume Morin <guillaume@morinfr.org> Cc: Ionut Alexa <ionut.m.alexa@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: umgwanakikbuti@gmail.com Cc: fweisbec@gmail.com Cc: srao@redhat.com Cc: lwoodman@redhat.com Cc: atheurer@redhat.com Link: http://lkml.kernel.org/r/20140816134010.26a9b572@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-08rcu: Remove local_irq_disable() in rcu_preempt_note_context_switch()Paul E. McKenney1-7/+9
The rcu_preempt_note_context_switch() function is on a scheduling fast path, so it would be good to avoid disabling irqs. The reason that irqs are disabled is to synchronize process-level and irq-handler access to the task_struct ->rcu_read_unlock_special bitmask. This commit therefore makes ->rcu_read_unlock_special instead be a union of bools with a short allowing single-access checks in RCU's __rcu_read_unlock(). This results in the process-level and irq-handler accesses being simple loads and stores, so that irqs need no longer be disabled. This commit therefore removes the irq disabling from rcu_preempt_note_context_switch(). Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-08rcu: Make TASKS_RCU handle nohz_full= CPUsPaul E. McKenney1-0/+2
Currently TASKS_RCU would ignore a CPU running a task in nohz_full= usermode execution. There would be neither a context switch nor a scheduling-clock interrupt to tell TASKS_RCU that the task in question had passed through a quiescent state. The grace period would therefore extend indefinitely. This commit therefore makes RCU's dyntick-idle subsystem record the task_struct structure of the task that is running in dyntick-idle mode on each CPU. The TASKS_RCU grace period can then access this information and record a quiescent state on behalf of any CPU running in dyntick-idle usermode. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-08rcu: Add call_rcu_tasks()Paul E. McKenney1-11/+12
This commit adds a new RCU-tasks flavor of RCU, which provides call_rcu_tasks(). This RCU flavor's quiescent states are voluntary context switch (not preemption!) and userspace execution (not the idle loop -- use some sort of schedule_on_each_cpu() if you need to handle the idle tasks. Note that unlike other RCU flavors, these quiescent states occur in tasks, not necessarily CPUs. Includes fixes from Steven Rostedt. This RCU flavor is assumed to have very infrequent latency-tolerant updaters. This assumption permits significant simplifications, including a single global callback list protected by a single global lock, along with a single task-private linked list containing all tasks that have not yet passed through a quiescent state. If experience shows this assumption to be incorrect, the required additional complexity will be added. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-08-25sched: Add function single_task_running to let a task check if it is the ↵Tim Chen1-0/+1
only task running on a cpu This function will help an async task processing batched jobs from workqueue decide if it wants to keep processing on more chunks of batched work that can be delayed, or to accumulate more work for more efficient batched processing later. If no other tasks are running on the cpu, the batching process can take advantgae of the available cpu cycles to a make decision to continue processing the existing accumulated work to minimize delay, otherwise it will yield. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-08-15Merge tag 'pm+acpi-3.17-rc1-2' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more ACPI and power management updates from Rafael Wysocki: "These are a couple of regression fixes, cpuidle menu governor optimizations, fixes for ACPI proccessor and battery drivers, hibernation fix to avoid problems related to the e820 memory map, fixes for a few cpufreq drivers and a new version of the suspend profiling tool analyze_suspend.py. Specifics: - Fix for an ACPI-based device hotplug regression introduced in 3.14 that causes a kernel panic to trigger when memory hot-remove is attempted with CONFIG_ACPI_HOTPLUG_MEMORY unset from Tang Chen - Fix for a cpufreq regression introduced in 3.16 that triggers a "sleeping function called from invalid context" bug in dev_pm_opp_init_cpufreq_table() from Stephen Boyd - ACPI battery driver fix for a warning message added in 3.16 that prints silly stuff sometimes from Mariusz Ceier - Hibernation fix for safer handling of mismatches in the 820 memory map between the configurations during image creation and during the subsequent restore from Chun-Yi Lee - ACPI processor driver fix to handle CPU hotplug notifications correctly during system suspend/resume from Lan Tianyu - Series of four cpuidle menu governor cleanups that also should speed it up a bit from Mel Gorman - Fixes for the speedstep-smi, integrator, cpu0 and arm_big_little cpufreq drivers from Hans Wennborg, Himangi Saraogi, Markus Pargmann and Uwe Kleine-König - Version 3.0 of the analyze_suspend.py suspend profiling tool from Todd E Brandt" * tag 'pm+acpi-3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI / battery: Fix warning message in acpi_battery_get_state() PM / tools: analyze_suspend.py: update to v3.0 cpufreq: arm_big_little: fix module license spec cpufreq: speedstep-smi: fix decimal printf specifiers ACPI / hotplug: Check scan handlers in acpi_scan_hot_remove() cpufreq: OPP: Avoid sleeping while atomic cpufreq: cpu0: Do not print error message when deferring cpufreq: integrator: Use set_cpus_allowed_ptr PM / hibernate: avoid unsafe pages in e820 reserved regions ACPI / processor: Make acpi_cpu_soft_notify() process CPU FROZEN events cpuidle: menu: Lookup CPU runqueues less cpuidle: menu: Call nr_iowait_cpu less times cpuidle: menu: Use ktime_to_us instead of reinventing the wheel cpuidle: menu: Use shifts when calculating averages where possible
2014-08-12Merge branches 'pm-sleep', 'pm-cpufreq' and 'pm-cpuidle'Rafael J. Wysocki1-2/+1
* pm-sleep: PM / hibernate: avoid unsafe pages in e820 reserved regions * pm-cpufreq: cpufreq: arm_big_little: fix module license spec cpufreq: speedstep-smi: fix decimal printf specifiers cpufreq: OPP: Avoid sleeping while atomic cpufreq: cpu0: Do not print error message when deferring cpufreq: integrator: Use set_cpus_allowed_ptr * pm-cpuidle: cpuidle: menu: Lookup CPU runqueues less cpuidle: menu: Call nr_iowait_cpu less times cpuidle: menu: Use ktime_to_us instead of reinventing the wheel cpuidle: menu: Use shifts when calculating averages where possible
2014-08-09Merge branch 'signal-cleanup' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc Pull arch signal handling cleanup from Richard Weinberger: "This patch series moves all remaining archs to the get_signal(), signal_setup_done() and sigsp() functions. Currently these archs use open coded variants of the said functions. Further, unused parameters get removed from get_signal_to_deliver(), tracehook_signal_handler() and signal_delivered(). At the end of the day we save around 500 lines of code." * 'signal-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc: (43 commits) powerpc: Use sigsp() openrisc: Use sigsp() mn10300: Use sigsp() mips: Use sigsp() microblaze: Use sigsp() metag: Use sigsp() m68k: Use sigsp() m32r: Use sigsp() hexagon: Use sigsp() frv: Use sigsp() cris: Use sigsp() c6x: Use sigsp() blackfin: Use sigsp() avr32: Use sigsp() arm64: Use sigsp() arc: Use sigsp() sas_ss_flags: Remove nested ternary if Rip out get_signal_to_deliver() Clean up signal_delivered() tracehook_signal_handler: Remove sig, info, ka and regs ...
2014-08-09shm: make exit_shm work proportional to task activityJack Miller1-0/+2
This is small set of patches our team has had kicking around for a few versions internally that fixes tasks getting hung on shm_exit when there are many threads hammering it at once. Anton wrote a simple test to cause the issue: http://ozlabs.org/~anton/junkcode/bust_shm_exit.c Before applying this patchset, this test code will cause either hanging tracebacks or pthread out of memory errors. After this patchset, it will still produce output like: root@somehost:~# ./bust_shm_exit 1024 160 ... INFO: rcu_sched detected stalls on CPUs/tasks: {} (detected by 116, t=2111 jiffies, g=241, c=240, q=7113) INFO: Stall ended before state dump start ... But the task will continue to run along happily, so we consider this an improvement over hanging, even if it's a bit noisy. This patch (of 3): exit_shm obtains the ipc_ns shm rwsem for write and holds it while it walks every shared memory segment in the namespace. Thus the amount of work is related to the number of shm segments in the namespace not the number of segments that might need to be cleaned. In addition, this occurs after the task has been notified the thread has exited, so the number of tasks waiting for the ns shm rwsem can grow without bound until memory is exausted. Add a list to the task struct of all shmids allocated by this task. Init the list head in copy_process. Use the ns->rwsem for locking. Add segments after id is added, remove before removing from id. On unshare of NEW_IPCNS orphan any ids as if the task had exited, similar to handling of semaphore undo. I chose a define for the init sequence since its a simple list init, otherwise it would require a function call to avoid include loops between the semaphore code and the task struct. Converting the list_del to list_del_init for the unshare cases would remove the exit followed by init, but I left it blow up if not inited. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Jack Miller <millerjo@us.ibm.com> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09kernel/fork.c: make mm_init_owner staticVladimir Davydov1-5/+0
It's only used in fork.c:mm_init(). Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09mm: memcontrol: use page lists for uncharge batchingJohannes Weiner1-6/+0
Pages are now uncharged at release time, and all sources of batched uncharges operate on lists of pages. Directly use those lists, and get rid of the per-task batching state. This also batches statistics accounting, in addition to the res counter charges, to reduce IRQ-disabling and re-enabling. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06cpuidle: menu: Lookup CPU runqueues lessMel Gorman1-2/+1
The menu governer makes separate lookups of the CPU runqueue to get load and number of IO waiters but it can be done with a single lookup. Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-08-06Merge branch 'next' of ↵Linus Torvalds1-3/+15
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "In this release: - PKCS#7 parser for the key management subsystem from David Howells - appoint Kees Cook as seccomp maintainer - bugfixes and general maintenance across the subsystem" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (94 commits) X.509: Need to export x509_request_asymmetric_key() netlabel: shorter names for the NetLabel catmap funcs/structs netlabel: fix the catmap walking functions netlabel: fix the horribly broken catmap functions netlabel: fix a problem when setting bits below the previously lowest bit PKCS#7: X.509 certificate issuer and subject are mandatory fields in the ASN.1 tpm: simplify code by using %*phN specifier tpm: Provide a generic means to override the chip returned timeouts tpm: missing tpm_chip_put in tpm_get_random() tpm: Properly clean sysfs entries in error path tpm: Add missing tpm_do_selftest to ST33 I2C driver PKCS#7: Use x509_request_asymmetric_key() Revert "selinux: fix the default socket labeling in sock_graft()" X.509: x509_request_asymmetric_keys() doesn't need string length arguments PKCS#7: fix sparse non static symbol warning KEYS: revert encrypted key change ima: add support for measuring and appraising firmware firmware_class: perform new LSM checks security: introduce kernel_fw_from_file hook PKCS#7: Missing inclusion of linux/err.h ...
2014-08-06sas_ss_flags: Remove nested ternary ifRichard Weinberger1-2/+4
...to make it readable. Signed-off-by: Richard Weinberger <richard@nod.at>
2014-08-06Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-4/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer and time updates from Thomas Gleixner: "A rather large update of timers, timekeeping & co - Core timekeeping code is year-2038 safe now for 32bit machines. Now we just need to fix all in kernel users and the gazillion of user space interfaces which rely on timespec/timeval :) - Better cache layout for the timekeeping internal data structures. - Proper nanosecond based interfaces for in kernel users. - Tree wide cleanup of code which wants nanoseconds but does hoops and loops to convert back and forth from timespecs. Some of it definitely belongs into the ugly code museum. - Consolidation of the timekeeping interface zoo. - A fast NMI safe accessor to clock monotonic for tracing. This is a long standing request to support correlated user/kernel space traces. With proper NTP frequency correction it's also suitable for correlation of traces accross separate machines. - Checkpoint/restart support for timerfd. - A few NOHZ[_FULL] improvements in the [hr]timer code. - Code move from kernel to kernel/time of all time* related code. - New clocksource/event drivers from the ARM universe. I'm really impressed that despite an architected timer in the newer chips SoC manufacturers insist on inventing new and differently broken SoC specific timers. [ Ed. "Impressed"? I don't think that word means what you think it means ] - Another round of code move from arch to drivers. Looks like most of the legacy mess in ARM regarding timers is sorted out except for a few obnoxious strongholds. - The usual updates and fixlets all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits) timekeeping: Fixup typo in update_vsyscall_old definition clocksource: document some basic timekeeping concepts timekeeping: Use cached ntp_tick_length when accumulating error timekeeping: Rework frequency adjustments to work better w/ nohz timekeeping: Minor fixup for timespec64->timespec assignment ftrace: Provide trace clocks monotonic timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC seqcount: Add raw_write_seqcount_latch() seqcount: Provide raw_read_seqcount() timekeeping: Use tk_read_base as argument for timekeeping_get_ns() timekeeping: Create struct tk_read_base and use it in struct timekeeper timekeeping: Restructure the timekeeper some more clocksource: Get rid of cycle_last clocksource: Move cycle_last validation to core code clocksource: Make delta calculation a function wireless: ath9k: Get rid of timespec conversions drm: vmwgfx: Use nsec based interfaces drm: i915: Use nsec based interfaces timekeeping: Provide ktime_get_raw() hangcheck-timer: Use ktime_get_ns() ...
2014-08-05Merge branch 'sched-core-for-linus' of ↵Linus Torvalds1-5/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Move the nohz kick code out of the scheduler tick to a dedicated IPI, from Frederic Weisbecker. This necessiated quite some background infrastructure rework, including: * Clean up some irq-work internals * Implement remote irq-work * Implement nohz kick on top of remote irq-work * Move full dynticks timer enqueue notification to new kick * Move multi-task notification to new kick * Remove unecessary barriers on multi-task notification - Remove proliferation of wait_on_bit() action functions and allow wait_on_bit_action() functions to support a timeout. (Neil Brown) - Another round of sched/numa improvements, cleanups and fixes. (Rik van Riel) - Implement fast idling of CPUs when the system is partially loaded, for better scalability. (Tim Chen) - Restructure and fix the CPU hotplug handling code that may leave cfs_rq and rt_rq's throttled when tasks are migrated away from a dead cpu. (Kirill Tkhai) - Robustify the sched topology setup code. (Peterz Zijlstra) - Improve sched_feat() handling wrt. static_keys (Jason Baron) - Misc fixes. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) sched/fair: Fix 'make xmldocs' warning caused by missing description sched: Use macro for magic number of -1 for setparam sched: Robustify topology setup sched: Fix sched_setparam() policy == -1 logic sched: Allow wait_on_bit_action() functions to support a timeout sched: Remove proliferation of wait_on_bit() action functions sched/numa: Revert "Use effective_load() to balance NUMA loads" sched: Fix static_key race with sched_feat() sched: Remove extra static_key*() function indirection sched/rt: Fix replenish_dl_entity() comments to match the current upstream code sched: Transform resched_task() into resched_curr() sched/deadline: Kill task_struct->pi_top_task sched: Rework check_for_tasks() sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime() sched/fair: Disable runtime_enabled on dying rq sched/numa: Change scan period code to match intent sched/numa: Rework best node setting in task_numa_migrate() sched/numa: Examine a task move when examining a task swap sched/numa: Simplify task_numa_compare() sched/numa: Use effective_load() to balance NUMA loads ...
2014-08-05Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds1-6/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU changes from Ingo Molar: "The main changes: - torture-test updates - callback-offloading changes - maintainership changes - update RCU documentation - miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits) rcu: Allow for NULL tick_nohz_full_mask when nohz_full= missing rcu: Fix a sparse warning in rcu_report_unblock_qs_rnp() rcu: Fix a sparse warning in rcu_initiate_boost() rcu: Fix __rcu_reclaim() to use true/false for bool rcu: Remove CONFIG_PROVE_RCU_DELAY rcu: Use __this_cpu_read() instead of per_cpu_ptr() rcu: Don't use NMIs to dump other CPUs' stacks rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUs rcu: Simplify priority boosting by putting rt_mutex in rcu_node rcu: Check both root and current rcu_node when setting up future grace period rcu: Allow post-unlock reference for rt_mutex rcu: Loosen __call_rcu()'s rcu_head alignment constraint rcu: Eliminate read-modify-write ACCESS_ONCE() calls rcu: Remove redundant ACCESS_ONCE() from tick_do_timer_cpu rcu: Make rcu node arrays static const char * const signal: Explain local_irq_save() call rcu: Handle obsolete references to TINY_PREEMPT_RCU rcu: Document deadlock-avoidance information for rcu_read_unlock() scripts: Teach get_maintainer.pl about the new "R:" tag rcu: Update rcu torture maintainership filename patterns ...
2014-07-28Merge branch 'sched/urgent' into sched/core, to merge fixes before applying ↵Ingo Molnar1-4/+4
new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-23delayacct: Make accounting nanosecond basedThomas Gleixner1-2/+2
Kill the timespec juggling and calculate with plain nanoseconds. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23sched: Make task->start_time nanoseconds basedThomas Gleixner1-1/+1
Simplify the timespec to nsec/usec conversions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23sched: Make task->real_start_time nanoseconds basedThomas Gleixner1-1/+1
Simplify the only user of this data by removing the timespec conversion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-18sched: move no_new_privs into new atomic flagsKees Cook1-3/+15
Since seccomp transitions between threads requires updates to the no_new_privs flag to be atomic, the flag must be part of an atomic flag set. This moves the nnp flag into a separate task field, and introduces accessors. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Andy Lutomirski <luto@amacapital.net>
2014-07-16sched: Transform resched_task() into resched_curr()Kirill Tkhai1-3/+3
We always use resched_task() with rq->curr argument. It's not possible to reschedule any task but rq's current. The patch introduces resched_curr(struct rq *) to replace all of the repeating patterns. The main aim is cleanup, but there is a little size profit too: (before) $ size kernel/sched/built-in.o text data bss dec hex filename 155274 16445 7042 178761 2ba49 kernel/sched/built-in.o $ size vmlinux text data bss dec hex filename 7411490 1178376 991232 9581098 92322a vmlinux (after) $ size kernel/sched/built-in.o text data bss dec hex filename 155130 16445 7042 178617 2b9b9 kernel/sched/built-in.o $ size vmlinux text data bss dec hex filename 7411362 1178376 991232 9580970 9231aa vmlinux I was choosing between resched_curr() and resched_rq(), and the first name looks better for me. A little lie in Documentation/trace/ftrace.txt. I have not actually collected the tracing again. With a hope the patch won't make execution times much worse :) Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20140628200219.1778.18735.stgit@localhost Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-16sched/deadline: Kill task_struct->pi_top_taskOleg Nesterov1-2/+0
Remove task_struct->pi_top_task. The only user, rt_mutex_setprio(), can use a local. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: Dario Faggioli <raistlin@linux.it> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Dempsky <mdempsky@chromium.org> Cc: Michal Simek <michal.simek@xilinx.com> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/20140606165206.GB29465@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-09rcu: Simplify priority boosting by putting rt_mutex in rcu_nodePaul E. McKenney1-6/+0
RCU priority boosting currently checks for boosting via a pointer in task_struct. However, this is not needed: As Oleg noted, if the rt_mutex is placed in the rcu_node instead of on the booster's stack, the boostee can simply check it see if it owns the lock. This commit makes this change, shrinking task_struct by one pointer and the kernel by thirteen lines. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-07-02sched: Fix compiler warningsGuenter Roeck1-4/+4
Commit 143e1e28cb (sched: Rework sched_domain topology definition) introduced a number of functions with a return value of 'const int'. gcc doesn't know what to do with that and, if the kernel is compiled with W=1, complains with the following warnings whenever sched.h is included. include/linux/sched.h:875:25: warning: type qualifiers ignored on function return type include/linux/sched.h:882:25: warning: type qualifiers ignored on function return type include/linux/sched.h:889:25: warning: type qualifiers ignored on function return type include/linux/sched.h:1002:21: warning: type qualifiers ignored on function return type Commits fb2aa855 (sched, ARM: Create a dedicated scheduler topology table) and 607b45e9a (sched, powerpc: Create a dedicated topology table) introduce the same warning in the arm and powerpc code. Drop 'const' from the function declarations to fix the problem. The fix for all three patches has to be applied together to avoid compilation failures for the affected architectures. Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1403658329-13196-1-git-send-email-linux@roeck-us.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-13Merge branch 'sched-core-for-linus' of ↵Linus Torvalds1-7/+7
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more scheduler updates from Ingo Molnar: "Second round of scheduler changes: - try-to-wakeup and IPI reduction speedups, from Andy Lutomirski - continued power scheduling cleanups and refactorings, from Nicolas Pitre - misc fixes and enhancements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Delete extraneous extern for to_ratio() sched/idle: Optimize try-to-wake-up IPI sched/idle: Simplify wake_up_idle_cpu() sched/idle: Clear polling before descheduling the idle thread sched, trace: Add a tracepoint for IPI-less remote wakeups cpuidle: Set polling in poll_idle sched: Remove redundant assignment to "rt_rq" in update_curr_rt(...) sched: Rename capacity related flags sched: Final power vs. capacity cleanups sched: Remove remaining dubious usage of "power" sched: Let 'struct sched_group_power' care about CPU capacity sched/fair: Disambiguate existing/remaining "capacity" usage sched/fair: Change "has_capacity" to "has_free_capacity" sched/fair: Remove "power" from 'struct numa_stats' sched: Fix signedness bug in yield_to() sched/fair: Use time_after() in record_wakee() sched/balancing: Reduce the rate of needless idle load balancing sched/fair: Fix unlocked reads of some cfs_b->quota/period
2014-06-13Merge branch 'perf-core-for-linus' of ↵Linus Torvalds1-1/+5
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more perf updates from Ingo Molnar: "A second round of perf updates: - wide reaching kprobes sanitization and robustization, with the hope of fixing all 'probe this function crashes the kernel' bugs, by Masami Hiramatsu. - uprobes updates from Oleg Nesterov: tmpfs support, corner case fixes and robustization work. - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo et al: * Add support to accumulate hist periods (Namhyung Kim) * various fixes, refactorings and enhancements" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits) perf: Differentiate exec() and non-exec() comm events perf: Fix perf_event_comm() vs. exec() assumption uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates perf/documentation: Add description for conditional branch filter perf/x86: Add conditional branch filtering support perf/tool: Add conditional branch filter 'cond' to perf record perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND' uprobes: Teach copy_insn() to support tmpfs uprobes: Shift ->readpage check from __copy_insn() to uprobe_register() perf/x86: Use common PMU interrupt disabled code perf/ARM: Use common PMU interrupt disabled code perf: Disable sampled events if no PMU interrupt perf: Fix use after free in perf_remove_from_context() perf tools: Fix 'make help' message error perf record: Fix poll return value propagation perf tools: Move elide bool into perf_hpp_fmt struct perf tools: Remove elide setup for SORT_MODE__MEMORY mode perf tools: Fix "==" into "=" in ui_browser__warning assignment perf tools: Allow overriding sysfs and proc finding with env var perf tools: Consider header files outside perf directory in tags target ...
2014-06-12Merge commit '3cf2f34' into sched/core, to fix build errorIngo Molnar1-4/+2
Fix this dependency on the locking tree's smp_mb*() API changes: kernel/sched/idle.c:247:3: error: implicit declaration of function ‘smp_mb__after_atomic’ [-Werror=implicit-function-declaration] Signed-off-by: Ingo Molnar <mingo@kernel.org>