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2016-12-14mm: add locked parameter to get_user_pages_remote()Lorenzo Stoakes1-2/+2
Patch series "mm: unexport __get_user_pages_unlocked()". This patch series continues the cleanup of get_user_pages*() functions taking advantage of the fact we can now pass gup_flags as we please. It firstly adds an additional 'locked' parameter to get_user_pages_remote() to allow for its callers to utilise VM_FAULT_RETRY functionality. This is necessary as the invocation of __get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of this and no other existing higher level function would allow it to do so. Secondly existing callers of __get_user_pages_unlocked() are replaced with the appropriate higher-level replacement - get_user_pages_unlocked() if the current task and memory descriptor are referenced, or get_user_pages_remote() if other task/memory descriptors are referenced (having acquiring mmap_sem.) This patch (of 2): Add a int *locked parameter to get_user_pages_remote() to allow VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked(). Taking into account the previous adjustments to get_user_pages*() functions allowing for the passing of gup_flags, we are now in a position where __get_user_pages_unlocked() need only be exported for his ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to subsequently unexport __get_user_pages_unlocked() as well as allowing for future flexibility in the use of get_user_pages_remote(). [sfr@canb.auug.org.au: merge fix for get_user_pages_remote API change] Link: http://lkml.kernel.org/r/20161122210511.024ec341@canb.auug.org.au Link: http://lkml.kernel.org/r/20161027095141.2569-2-lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kernel/watchdog.c: move hardlockup detector to separate fileBabu Moger3-230/+239
Separate hardlockup code from watchdog.c and move it to watchdog_hld.c. It is mostly straight forward. Remove everything inside CONFIG_HARDLOCKUP_DETECTORS. This code will go to file watchdog_hld.c. Also update the makefile accordigly. Link: http://lkml.kernel.org/r/1478034826-43888-3-git-send-email-babu.moger@oracle.com Signed-off-by: Babu Moger <babu.moger@oracle.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Andi Kleen <andi@firstfloor.org> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Josh Hunt <johunt@akamai.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kernel/watchdog.c: move shared definitions to nmi.hBabu Moger1-24/+4
Patch series "Clean up watchdog handlers", v2. This is an attempt to cleanup watchdog handlers. Right now, kernel/watchdog.c implements both softlockup and hardlockup detectors. Softlockup code is generic. Hardlockup code is arch specific. Some architectures don't use hardlockup detectors. They use their own watchdog detectors. To make both these combination work, we have numerous #ifdefs in kernel/watchdog.c. We are trying here to make these handlers independent of each other. Also provide an interface for architectures to implement their own handlers. watchdog_nmi_enable and watchdog_nmi_disable will be defined as weak such that architectures can override its definitions. Thanks to Don Zickus for his suggestions. Here are our previous discussions http://www.spinics.net/lists/sparclinux/msg16543.html http://www.spinics.net/lists/sparclinux/msg16441.html This patch (of 3): Move shared macros and definitions to nmi.h so that watchdog.c, new file watchdog_hld.c or any other architecture specific handler can use those definitions. Link: http://lkml.kernel.org/r/1478034826-43888-2-git-send-email-babu.moger@oracle.com Signed-off-by: Babu Moger <babu.moger@oracle.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Andi Kleen <andi@firstfloor.org> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Josh Hunt <johunt@akamai.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14posix-timers: give lazy compilers some help optimizing code awayNicolas Pitre1-1/+2
The OpenRISC compiler (so far) fails to optimize away a large portion of code containing a reference to posix_timer_event in alarmtimer.c when CONFIG_POSIX_TIMERS is unset. Let's give it a direct clue to let the build succeed. This fixes [linux-next:master 6682/7183] alarmtimer.c:undefined reference to `posix_timer_event' reported by kbuild test robot. Signed-off-by: Nicolas Pitre <nico@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kdb: call vkdb_printf() from vprintk_default() only when wantedPetr Mladek2-8/+4
kdb_trap_printk allows to pass normal printk() messages to kdb via vkdb_printk(). For example, it is used to get backtrace using the classic show_stack(), see kdb_show_stack(). vkdb_printf() tries to avoid a potential infinite loop by disabling the trap. But this approach is racy, for example: CPU1 CPU2 vkdb_printf() // assume that kdb_trap_printk == 0 saved_trap_printk = kdb_trap_printk; kdb_trap_printk = 0; kdb_show_stack() kdb_trap_printk++; Problem1: Now, a nested printk() on CPU0 calls vkdb_printf() even when it should have been disabled. It will not cause a deadlock but... // using the outdated saved value: 0 kdb_trap_printk = saved_trap_printk; kdb_trap_printk--; Problem2: Now, kdb_trap_printk == -1 and will stay like this. It means that all messages will get passed to kdb from now on. This patch removes the racy saved_trap_printk handling. Instead, the recursion is prevented by a check for the locked CPU. The solution is still kind of racy. A non-related printk(), from another process, might get trapped by vkdb_printf(). And the wanted printk() might not get trapped because kdb_printf_cpu is assigned. But this problem existed even with the original code. A proper solution would be to get_cpu() before setting kdb_trap_printk and trap messages only from this CPU. I am not sure if it is worth the effort, though. In fact, the race is very theoretical. When kdb is running any of the commands that use kdb_trap_printk there is a single active CPU and the other CPUs should be in a holding pen inside kgdb_cpu_enter(). The only time this is violated is when there is a timeout waiting for the other CPUs to report to the holding pen. Finally, note that the situation is a bit schizophrenic. vkdb_printf() explicitly allows recursion but only from KDB code that calls kdb_printf() directly. On the other hand, the generic printk() recursion is not allowed because it might cause an infinite loop. This is why we could not hide the decision inside vkdb_printf() easily. Link: http://lkml.kernel.org/r/1480412276-16690-4-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kdb: properly synchronize vkdb_printf() calls with other CPUsPetr Mladek2-18/+13
kdb_printf_lock does not prevent other CPUs from entering the critical section because it is ignored when KDB_STATE_PRINTF_LOCK is set. The problematic situation might look like: CPU0 CPU1 vkdb_printf() if (!KDB_STATE(PRINTF_LOCK)) KDB_STATE_SET(PRINTF_LOCK); spin_lock_irqsave(&kdb_printf_lock, flags); vkdb_printf() if (!KDB_STATE(PRINTF_LOCK)) BANG: The PRINTF_LOCK state is set and CPU1 is entering the critical section without spinning on the lock. The problem is that the code tries to implement locking using two state variables that are not handled atomically. Well, we need a custom locking because we want to allow reentering the critical section on the very same CPU. Let's use solution from Petr Zijlstra that was proposed for a similar scenario, see https://lkml.kernel.org/r/20161018171513.734367391@infradead.org This patch uses the same trick with cmpxchg(). The only difference is that we want to handle only recursion from the same context and therefore we disable interrupts. In addition, KDB_STATE_PRINTF_LOCK is removed. In fact, we are not able to set it a non-racy way. Link: http://lkml.kernel.org/r/1480412276-16690-3-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kdb: remove unused kdb_event handlingPetr Mladek2-3/+0
kdb_event state variable is only set but never checked in the kernel code. http://www.spinics.net/lists/kdb/msg01733.html suggests that this variable affected WARN_CONSOLE_UNLOCKED() in the original implementation. But this check never went upstream. The semantic is unclear and racy. The value is updated after the kdb_printf_lock is acquired and after it is released. It should be symmetric at minimum. The value should be manipulated either inside or outside the locked area. Fortunately, it seems that the original function is gone and we could simply remove the state variable. Link: http://lkml.kernel.org/r/1480412276-16690-2-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kernel/debug/debug_core.c: more properly delay for secondary CPUsDouglas Anderson1-2/+2
We've got a delay loop waiting for secondary CPUs. That loop uses loops_per_jiffy. However, loops_per_jiffy doesn't actually mean how many tight loops make up a jiffy on all architectures. It is quite common to see things like this in the boot log: Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=24000) In my case I was seeing lots of cases where other CPUs timed out entering the debugger only to print their stack crawls shortly after the kdb> prompt was written. Elsewhere in kgdb we already use udelay(), so that should be safe enough to use to implement our timeout. We'll delay 1 ms for 1000 times, which should give us a full second of delay (just like the old code wanted) but allow us to notice that we're done every 1 ms. [akpm@linux-foundation.org: simplifications, per Daniel] Link: http://lkml.kernel.org/r/1477091361-2039-1-git-send-email-dianders@chromium.org Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Brian Norris <briannorris@chromium.org> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kcov: add more missing includesKefeng Wang1-0/+5
It is fragile that some definitions acquired via transitive dependencies, as shown in below: atomic_* (<linux/atomic.h>) ENOMEM/EN* (<linux/errno.h>) EXPORT_SYMBOL (<linux/export.h>) device_initcall (<linux/init.h>) preempt_* (<linux/preempt.h>) Include them to prevent possible issues. Link: http://lkml.kernel.org/r/1481163221-40170-1-git-send-email-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Suggested-by: Mark Rutland <mark.rutland@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14relay: check array offset before using itDan Carpenter1-2/+2
Smatch complains that we started using the array offset before we checked that it was valid. Fixes: 017c59c042d0 ('relay: Use per CPU constructs for the relay channel buffer pointers') Link: http://lkml.kernel.org/r/20161013084947.GC16198@mwanda Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14sysctl: add KERN_CONT to deprecated_sysctl_warning()Tetsuo Handa1-2/+2
Do not break lines while printk()ing values. kernel: warning: process `tomoyo_file_tes' used the deprecated sysctl system call with kernel: 3. kernel: 5. kernel: 56. kernel: Link: http://lkml.kernel.org/r/1480814833-4976-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kexec: add cond_resched into kimage_alloc_crash_control_pageszhong jiang1-0/+2
A soft lookup will occur when I run trinity in syscall kexec_load. the corresponding stack information is as follows. BUG: soft lockup - CPU#6 stuck for 22s! [trinity-c6:13859] Kernel panic - not syncing: softlockup: hung tasks CPU: 6 PID: 13859 Comm: trinity-c6 Tainted: G O L ----V------- 3.10.0-327.28.3.35.zhongjiang.x86_64 #1 Hardware name: Huawei Technologies Co., Ltd. Tecal BH622 V2/BC01SRSA0, BIOS RMIBV386 06/30/2014 Call Trace: <IRQ> dump_stack+0x19/0x1b panic+0xd8/0x214 watchdog_timer_fn+0x1cc/0x1e0 __hrtimer_run_queues+0xd2/0x260 hrtimer_interrupt+0xb0/0x1e0 ? call_softirq+0x1c/0x30 local_apic_timer_interrupt+0x37/0x60 smp_apic_timer_interrupt+0x3f/0x60 apic_timer_interrupt+0x6d/0x80 <EOI> ? kimage_alloc_control_pages+0x80/0x270 ? kmem_cache_alloc_trace+0x1ce/0x1f0 ? do_kimage_alloc_init+0x1f/0x90 kimage_alloc_init+0x12a/0x180 SyS_kexec_load+0x20a/0x260 system_call_fastpath+0x16/0x1b the first time allocation of control pages may take too much time because crash_res.end can be set to a higher value. we need to add cond_resched to avoid the issue. The patch have been tested and above issue is not appear. Link: http://lkml.kernel.org/r/1481164674-42775-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Xunlei Pang <xpang@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kexec: export the value of phys_base instead of symbol addressBaoquan He1-3/+0
Currently in x86_64, the symbol address of phys_base is exported to vmcoreinfo. Dave Anderson complained this is really useless for his Crash implementation. Because in user-space utility Crash and Makedumpfile which exported vmcore information is mainly used for, value of phys_base is needed to covert virtual address of exported kernel symbol to physical address. Especially init_level4_pgt, if we want to access and go over the page table to look up a PA corresponding to VA, firstly we need calculate page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map + phys_base; Now in Crash and Makedumpfile, we have to analyze the vmcore elf program header to get value of phys_base. As Dave said, it would be preferable if it were readily availabl in vmcoreinfo rather than depending upon the PT_LOAD semantics. Hence in this patch change to export the value of phys_base instead of its virtual address. And people also complained that KERNEL_IMAGE_SIZE exporting is x86_64 only, should be moved into arch dependent function arch_crash_save_vmcoreinfo. Do the moving in this patch. Link: http://lkml.kernel.org/r/1478568596-30060-2-git-send-email-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Thomas Garnier <thgarnie@google.com> Cc: Baoquan He <bhe@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Xunlei Pang <xlpang@redhat.com> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Cc: Kees Cook <keescook@chromium.org> Cc: Eugene Surovegin <surovegin@google.com> Cc: Dave Young <dyoung@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com> Cc: Dave Anderson <anderson@redhat.com> Cc: Pratyush Anand <panand@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14coredump: clarify "unsafe core_pattern" warningAlexey Dobriyan1-3/+5
I was amused to find "unsafe core_pattern" warning having these lines in /etc/sysctl.conf: fs.suid_dumpable=2 kernel.core_pattern=/core/core-%e-%p-%E kernel.core_uses_pid=0 Turns out kernel is formally right. Default core_pattern is just "core", which doesn't qualify for secure path while setting suid.dumpable. Hint admins about solution, clarify sysctl names, delete unnecessary '\' characters (string literals are concatenated regardless) and reformat for easier grepping. Link: http://lkml.kernel.org/r/20161029152124.GA1258@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14signals: avoid unnecessary taking of sighand->siglockWaiman Long1-0/+7
When running certain database workload on a high-end system with many CPUs, it was found that spinlock contention in the sigprocmask syscalls became a significant portion of the overall CPU cycles as shown below. 9.30% 9.30% 905387 dataserver /proc/kcore 0x7fff8163f4d2 [k] _raw_spin_lock_irq | ---_raw_spin_lock_irq | |--99.34%-- __set_current_blocked | sigprocmask | sys_rt_sigprocmask | system_call_fastpath | | | |--50.63%-- __swapcontext | | | | | |--99.91%-- upsleepgeneric | | | |--49.36%-- __setcontext | | ktskRun Looking further into the swapcontext function in glibc, it was found that the function always call sigprocmask() without checking if there are changes in the signal mask. A check was added to the __set_current_blocked() function to avoid taking the sighand->siglock spinlock if there is no change in the signal mask. This will prevent unneeded spinlock contention when many threads are trying to call sigprocmask(). With this patch applied, the spinlock contention in sigprocmask() was gone. Link: http://lkml.kernel.org/r/1474979209-11867-1-git-send-email-Waiman.Long@hpe.com Signed-off-by: Waiman Long <Waiman.Long@hpe.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Stas Sergeev <stsp@list.ru> Cc: Scott J Norton <scott.norton@hpe.com> Cc: Douglas Hatch <doug.hatch@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14kernel/watchdog: use nmi registers snapshot in hardlockup handlerKonstantin Khlebnikov1-1/+0
NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ. Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP pointing to the code interrupted by IRQ which was interrupted by NMI. NULL isn't a problem: in this case watchdog calls dump_stack() and prints full stack trace including NMI. But if we're stuck in IRQ handler then NMI watchlog will print stack trace without IRQ part at all. This patch uses registers snapshot passed into NMI handler as arguments: these registers point exactly to the instruction interrupted by NMI. Fixes: 55537871ef66 ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup") Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: <stable@vger.kernel.org> [4.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-13Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds2-28/+86
Pull workqueue updates from Tejun Heo: "Mostly patches to initialize workqueue subsystem earlier and get rid of keventd_up(). The patches were headed for the last merge cycle but got delayed due to a bug found late minute, which is fixed now. Also, to help debugging, destroy_workqueue() is more chatty now on a sanity check failure." * 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: move wq_numa_init() to workqueue_init() workqueue: remove keventd_up() debugobj, workqueue: remove keventd_up() usage slab, workqueue: remove keventd_up() usage power, workqueue: remove keventd_up() usage tty, workqueue: remove keventd_up() usage mce, workqueue: remove keventd_up() usage workqueue: make workqueue available early during boot workqueue: dump workqueue state on sanity check failures in destroy_workqueue()
2016-12-13Merge tag 'pm-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pmLinus Torvalds7-118/+342
Pull power management updates from Rafael Wysocki: "Again, cpufreq gets more changes than the other parts this time (one new driver, one old driver less, a bunch of enhancements of the existing code, new CPU IDs, fixes, cleanups) There also are some changes in cpuidle (idle injection rework, a couple of new CPU IDs, online/offline rework in intel_idle, fixes and cleanups), in the generic power domains framework (mostly related to supporting power domains containing CPUs), and in the Operating Performance Points (OPP) library (mostly related to supporting devices with multiple voltage regulators) In addition to that, the system sleep state selection interface is modified to make it easier for distributions with unchanged user space to support suspend-to-idle as the default system suspend method, some issues are fixed in the PM core, the latency tolerance PM QoS framework is improved a bit, the Intel RAPL power capping driver is cleaned up and there are some fixes and cleanups in the devfreq subsystem Specifics: - New cpufreq driver for Broadcom STB SoCs and a Device Tree binding for it (Markus Mayer) - Support for ARM Integrator/AP and Integrator/CP in the generic DT cpufreq driver and elimination of the old Integrator cpufreq driver (Linus Walleij) - Support for the zx296718, r8a7743 and r8a7745, Socionext UniPhier, and PXA SoCs in the the generic DT cpufreq driver (Baoyou Xie, Geert Uytterhoeven, Masahiro Yamada, Robert Jarzmik) - cpufreq core fix to eliminate races that may lead to using inactive policy objects and related cleanups (Rafael Wysocki) - cpufreq schedutil governor update to make it use SCHED_FIFO kernel threads (instead of regular workqueues) for doing delayed work (to reduce the response latency in some cases) and related cleanups (Viresh Kumar) - New cpufreq sysfs attribute for resetting statistics (Markus Mayer) - cpufreq governors fixes and cleanups (Chen Yu, Stratos Karafotis, Viresh Kumar) - Support for using generic cpufreq governors in the intel_pstate driver (Rafael Wysocki) - Support for per-logical-CPU P-state limits and the EPP/EPB (Energy Performance Preference/Energy Performance Bias) knobs in the intel_pstate driver (Srinivas Pandruvada) - New CPU ID for Knights Mill in intel_pstate (Piotr Luc) - intel_pstate driver modification to use the P-state selection algorithm based on CPU load on platforms with the system profile in the ACPI tables set to "mobile" (Srinivas Pandruvada) - intel_pstate driver cleanups (Arnd Bergmann, Rafael Wysocki, Srinivas Pandruvada) - cpufreq powernv driver updates including fast switching support (for the schedutil governor), fixes and cleanus (Akshay Adiga, Andrew Donnellan, Denis Kirjanov) - acpi-cpufreq driver rework to switch it over to the new CPU offline/online state machine (Sebastian Andrzej Siewior) - Assorted cleanups in cpufreq drivers (Wei Yongjun, Prashanth Prakash) - Idle injection rework (to make it use the regular idle path instead of a home-grown custom one) and related powerclamp thermal driver updates (Peter Zijlstra, Jacob Pan, Petr Mladek, Sebastian Andrzej Siewior) - New CPU IDs for Atom Z34xx and Knights Mill in intel_idle (Andy Shevchenko, Piotr Luc) - intel_idle driver cleanups and switch over to using the new CPU offline/online state machine (Anna-Maria Gleixner, Sebastian Andrzej Siewior) - cpuidle DT driver update to support suspend-to-idle properly (Sudeep Holla) - cpuidle core cleanups and misc updates (Daniel Lezcano, Pan Bian, Rafael Wysocki) - Preliminary support for power domains including CPUs in the generic power domains (genpd) framework and related DT bindings (Lina Iyer) - Assorted fixes and cleanups in the generic power domains (genpd) framework (Colin Ian King, Dan Carpenter, Geert Uytterhoeven) - Preliminary support for devices with multiple voltage regulators and related fixes and cleanups in the Operating Performance Points (OPP) library (Viresh Kumar, Masahiro Yamada, Stephen Boyd) - System sleep state selection interface rework to make it easier to support suspend-to-idle as the default system suspend method (Rafael Wysocki) - PM core fixes and cleanups, mostly related to the interactions between the system suspend and runtime PM frameworks (Ulf Hansson, Sahitya Tummala, Tony Lindgren) - Latency tolerance PM QoS framework imorovements (Andrew Lutomirski) - New Knights Mill CPU ID for the Intel RAPL power capping driver (Piotr Luc) - Intel RAPL power capping driver fixes, cleanups and switch over to using the new CPU offline/online state machine (Jacob Pan, Thomas Gleixner, Sebastian Andrzej Siewior) - Fixes and cleanups in the exynos-ppmu, exynos-nocp, rk3399_dmc, rockchip-dfi devfreq drivers and the devfreq core (Axel Lin, Chanwoo Choi, Javier Martinez Canillas, MyungJoo Ham, Viresh Kumar) - Fix for false-positive KASAN warnings during resume from ACPI S3 (suspend-to-RAM) on x86 (Josh Poimboeuf) - Memory map verification during resume from hibernation on x86 to ensure a consistent address space layout (Chen Yu) - Wakeup sources debugging enhancement (Xing Wei) - rockchip-io AVS driver cleanup (Shawn Lin)" * tag 'pm-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (127 commits) devfreq: rk3399_dmc: Don't use OPP structures outside of RCU locks devfreq: rk3399_dmc: Remove dangling rcu_read_unlock() devfreq: exynos: Don't use OPP structures outside of RCU locks Documentation: intel_pstate: Document HWP energy/performance hints cpufreq: intel_pstate: Support for energy performance hints with HWP cpufreq: intel_pstate: Add locking around HWP requests PM / sleep: Print active wakeup sources when blocking on wakeup_count reads PM / core: Fix bug in the error handling of async suspend PM / wakeirq: Fix dedicated wakeirq for drivers not using autosuspend PM / Domains: Fix compatible for domain idle state PM / OPP: Don't WARN on multiple calls to dev_pm_opp_set_regulators() PM / OPP: Allow platform specific custom set_opp() callbacks PM / OPP: Separate out _generic_set_opp() PM / OPP: Add infrastructure to manage multiple regulators PM / OPP: Pass struct dev_pm_opp_supply to _set_opp_voltage() PM / OPP: Manage supply's voltage/current in a separate structure PM / OPP: Don't use OPP structure outside of rcu protected section PM / OPP: Reword binding supporting multiple regulators per device PM / OPP: Fix incorrect cpu-supply property in binding cpuidle: Add a kerneldoc comment to cpuidle_use_deepest_state() ..
2016-12-13Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-blockLinus Torvalds2-17/+16
Pull block layer updates from Jens Axboe: "This is the main block pull request this series. Contrary to previous release, I've kept the core and driver changes in the same branch. We always ended up having dependencies between the two for obvious reasons, so makes more sense to keep them together. That said, I'll probably try and keep more topical branches going forward, especially for cycles that end up being as busy as this one. The major parts of this pull request is: - Improved support for O_DIRECT on block devices, with a small private implementation instead of using the pig that is fs/direct-io.c. From Christoph. - Request completion tracking in a scalable fashion. This is utilized by two components in this pull, the new hybrid polling and the writeback queue throttling code. - Improved support for polling with O_DIRECT, adding a hybrid mode that combines pure polling with an initial sleep. From me. - Support for automatic throttling of writeback queues on the block side. This uses feedback from the device completion latencies to scale the queue on the block side up or down. From me. - Support from SMR drives in the block layer and for SD. From Hannes and Shaun. - Multi-connection support for nbd. From Josef. - Cleanup of request and bio flags, so we have a clear split between which are bio (or rq) private, and which ones are shared. From Christoph. - A set of patches from Bart, that improve how we handle queue stopping and starting in blk-mq. - Support for WRITE_ZEROES from Chaitanya. - Lightnvm updates from Javier/Matias. - Supoort for FC for the nvme-over-fabrics code. From James Smart. - A bunch of fixes from a whole slew of people, too many to name here" * 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits) blk-stat: fix a few cases of missing batch flushing blk-flush: run the queue when inserting blk-mq flush elevator: make the rqhash helpers exported blk-mq: abstract out blk_mq_dispatch_rq_list() helper blk-mq: add blk_mq_start_stopped_hw_queue() block: improve handling of the magic discard payload blk-wbt: don't throttle discard or write zeroes nbd: use dev_err_ratelimited in io path nbd: reset the setup task for NBD_CLEAR_SOCK nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME nvme-fabrics: Add target support for FC transport nvme-fabrics: Add host support for FC transport nvme-fabrics: Add FC transport LLDD api definitions nvme-fabrics: Add FC transport FC-NVME definitions nvme-fabrics: Add FC transport error codes to nvme.h Add type 0x28 NVME type code to scsi fc headers nvme-fabrics: patch target code in prep for FC transport support nvme-fabrics: set sqe.command_id in core not transports parser: add u64 number parser nvme-rdma: align to generic ib_event logging helper ...
2016-12-13Merge tag 'pstore-v4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linuxLinus Torvalds1-0/+17
Pull pstore updates from Kees Cook: "Improvements and fixes to pstore subsystem: - add additional checks for bad platform data - remove bounce buffer in console writer - protect read/unlink race with a mutex - correctly give up during dump locking failures - increase ftrace bandwidth by splitting ftrace buffers per CPU" * tag 'pstore-v4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: ramoops: add pdata NULL check to ramoops_probe pstore: Convert console write to use ->write_buf pstore: Protect unlink with read_mutex pstore: Use global ftrace filters for function trace filtering ftrace: Provide API to use global filtering for ftrace ops pstore: Clarify context field przs as dprzs pstore: improve error report for failed setup pstore: Merge per-CPU ftrace records into one pstore: Add ftrace timestamp counter ramoops: Split ftrace buffer space into per-CPU zones pstore: Make ramoops_init_przs generic for other prz arrays pstore: Allow prz to control need for locking pstore: Warn on PSTORE_TYPE_PMSG using deprecated function pstore: Make spinlock per zone instead of global pstore: Actually give up during locking failure
2016-12-12Merge branch 'akpm' (patches from Andrew)Linus Torvalds6-45/+60
Merge updates from Andrew Morton: - various misc bits - most of MM (quite a lot of MM material is awaiting the merge of linux-next dependencies) - kasan - printk updates - procfs updates - MAINTAINERS - /lib updates - checkpatch updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (123 commits) init: reduce rootwait polling interval time to 5ms binfmt_elf: use vmalloc() for allocation of vma_filesz checkpatch: don't emit unified-diff error for rename-only patches checkpatch: don't check c99 types like uint8_t under tools checkpatch: avoid multiple line dereferences checkpatch: don't check .pl files, improve absolute path commit log test scripts/checkpatch.pl: fix spelling checkpatch: don't try to get maintained status when --no-tree is given lib/ida: document locking requirements a bit better lib/rbtree.c: fix typo in comment of ____rb_erase_color lib/Kconfig.debug: make CONFIG_STRICT_DEVMEM depend on CONFIG_DEVMEM MAINTAINERS: add drm and drm/i915 irc channels MAINTAINERS: add "C:" for URI for chat where developers hang out MAINTAINERS: add drm and drm/i915 bug filing info MAINTAINERS: add "B:" for URI where to file bugs get_maintainer: look for arbitrary letter prefixes in sections printk: add Kconfig option to set default console loglevel printk/sound: handle more message headers printk/btrfs: handle more message headers printk/kdb: handle more message headers ...
2016-12-12Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds2-38/+38
Pull irq updates from Thomas Gleixner: "The irq department provides: - a major update to the auto affinity management code, which is used by multi-queue devices - move of the microblaze irq chip driver into the common driver code so it can be shared between microblaze, powerpc and MIPS - a series of updates to the ARM GICV3 interrupt controller - the usual pile of fixes and small improvements all over the place" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits) powerpc/virtex: Use generic xilinx irqchip driver irqchip/xilinx: Try to fall back if xlnx,kind-of-intr not provided irqchip/xilinx: Add support for parent intc irqchip/xilinx: Rename get_irq to xintc_get_irq irqchip/xilinx: Restructure and use jump label api irqchip/xilinx: Clean up print messages microblaze/irqchip: Move intc driver to irqchip ARM: virt: Select ARM_GIC_V3_ITS ARM: gic-v3-its: Add 32bit support to GICv3 ITS irqchip/gic-v3-its: Specialise readq and writeq accesses irqchip/gic-v3-its: Specialise flush_dcache operation irqchip/gic-v3-its: Narrow down Entry Size when used as a divider irqchip/gic-v3-its: Change unsigned types for AArch32 compatibility irqchip/gic-v3: Use nops macro for Cavium ThunderX erratum 23154 irqchip/gic-v3: Convert arm64 GIC accessors to {read,write}_sysreg_s genirq/msi: Drop artificial PCI dependency irqchip/bcm7038-l1: Implement irq_cpu_offline() callback genirq/affinity: Use default affinity mask for reserved vectors genirq/affinity: Take reserved vectors into account when spreading irqs PCI: Remove the irq_affinity mask from struct pci_dev ...
2016-12-12Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds14-97/+307
Pull timer updates from Thomas Gleixner: "The time/timekeeping/timer folks deliver with this update: - Fix a reintroduced signed/unsigned issue and cleanup the whole signed/unsigned mess in the timekeeping core so this wont happen accidentaly again. - Add a new trace clock based on boot time - Prevent injection of random sleep times when PM tracing abuses the RTC for storage - Make posix timers configurable for real tiny systems - Add tracepoints for the alarm timer subsystem so timer based suspend wakeups can be instrumented - The usual pile of fixes and updates to core and drivers" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) timekeeping: Use mul_u64_u32_shr() instead of open coding it timekeeping: Get rid of pointless typecasts timekeeping: Make the conversion call chain consistently unsigned timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion alarmtimer: Add tracepoints for alarm timers trace: Update documentation for mono, mono_raw and boot clock trace: Add an option for boot clock as trace clock timekeeping: Add a fast and NMI safe boot clock timekeeping/clocksource_cyc2ns: Document intended range limitation timekeeping: Ignore the bogus sleep time if pm_trace is enabled selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous" clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map() arm64: dts: rockchip: Arch counter doesn't tick in system suspend clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend posix-timers: Make them configurable posix_cpu_timers: Move the add_device_randomness() call to a proper place timer: Move sys_alarm from timer.c to itimer.c ptp_clock: Allow for it to be optional Kconfig: Regenerate *.c_shipped files after previous changes ...
2016-12-12Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds4-124/+86
Pull smp hotplug updates from Thomas Gleixner: "This is the final round of converting the notifier mess to the state machine. The removal of the notifiers and the related infrastructure will happen around rc1, as there are conversions outstanding in other trees. The whole exercise removed about 2000 lines of code in total and in course of the conversion several dozen bugs got fixed. The new mechanism allows to test almost every hotplug step standalone, so usage sites can exercise all transitions extensively. There is more room for improvement, like integrating all the pointlessly different architecture mechanisms of synchronizing, setting cpus online etc into the core code" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits) tracing/rb: Init the CPU mask on allocation soc/fsl/qbman: Convert to hotplug state machine soc/fsl/qbman: Convert to hotplug state machine zram: Convert to hotplug state machine KVM/PPC/Book3S HV: Convert to hotplug state machine arm64/cpuinfo: Convert to hotplug state machine arm64/cpuinfo: Make hotplug notifier symmetric mm/compaction: Convert to hotplug state machine iommu/vt-d: Convert to hotplug state machine mm/zswap: Convert pool to hotplug state machine mm/zswap: Convert dst-mem to hotplug state machine mm/zsmalloc: Convert to hotplug state machine mm/vmstat: Convert to hotplug state machine mm/vmstat: Avoid on each online CPU loops mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead() tracing/rb: Convert to hotplug state machine oprofile/nmi timer: Convert to hotplug state machine net/iucv: Use explicit clean up labels in iucv_init() x86/pci/amd-bus: Convert to hotplug state machine x86/oprofile/nmi: Convert to hotplug state machine ...
2016-12-12printk/kdb: handle more message headersPetr Mladek1-1/+1
Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") allows to define more message headers for a single message. The motivation is that continuous lines might get mixed. Therefore it make sense to define the right log level for every piece of a cont line. This patch introduces printk_skip_headers() that will skip all headers and uses it in the kdb code instead of printk_skip_level(). This approach helps to fix other printk_skip_level() users independently. Link: http://lkml.kernel.org/r/1478695291-12169-3-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Joe Perches <joe@perches.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: David Sterba <dsterba@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12printk/NMI: handle continuous lines and missing newlinePetr Mladek1-28/+50
Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") added back KERN_CONT message header. As a result it might appear in the middle of the line when the parts are squashed via the temporary NMI buffer. A reasonable solution seems to be to split the text in the NNI temporary not only by newlines but also by the message headers. Another solution would be to filter out KERN_CONT when writing to the temporary buffer. But this would complicate the lockless handling. Also it would not solve problems with a missing newline that was there even before the KERN_CONT stuff. This patch moves the temporary buffer handling into separate function. I played with it and it seems that using the char pointers make the code easier to read. Also it prints the final newline as a continuous line. Finally, it moves handling of the s->len overflow into the paranoid check. And allows to recover from the disaster. Link: http://lkml.kernel.org/r/1478695291-12169-2-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: David Sterba <dsterba@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12printk/NMI: fix up handling of the full nmi log bufferPetr Mladek1-2/+3
vsnprintf() adds the trailing '\0' but it does not count it into the number of printed characters. The result is that there is one byte less space for the real characters in the buffer. The broken check for the free space might cause that we will repeatedly try to print 1 character into the buffer, never reach the full buffer, and do not count the messages as missed. Also vsnprintf() returns the number of characters that would be printed if the buffer was big enough. As a result, s->len might be bigger than the size of the buffer[*]. And the printk() function might return bigger len than it really printed. Both problems are fixed by using vscnprintf() instead. Note that I though about increasing the number of missed messages even when the message was shrunken. But it made the code even more complicated. I think that it is not worth it. Shrunken messages are usually easy to recognize. And it should be a corner case. [*] The overflown s->len value is crazy and unexpected. I "made a mistake" and reported this situation as an internal error when fixed handling of PR_CONT headers in some other patch. Link: http://lkml.kernel.org/r/20161208174912.GA17042@linux.suse Signed-off-by: Petr Mladek <pmladek@suse.com> CcL Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Joe Perches <joe@perches.com> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Takashi Iwai <tiwai@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12hung_task: decrement sysctl_hung_task_warnings only if it is positiveTetsuo Handa1-1/+2
Since sysctl_hung_task_warnings == -1 is allowed (infinite warnings), commit 48a6d64edadb ("hung_task: allow hung_task_panic when hung_task_warnings is 0") should decrement it only when it is not -1. This prevents the kernel from ceasing warnings after the first 4294967295 ;) Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: John Siddle <jsiddle@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12kernel/fork: use vfree_atomic() to free thread stackAndrey Ryabinin1-1/+1
vfree() is going to use sleeping lock. Thread stack freed in atomic context, therefore we must use vfree_atomic() here. Link: http://lkml.kernel.org/r/1479474236-4139-6-git-send-email-hch@lst.de Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Joel Fernandes <joelaf@google.com> Cc: Jisheng Zhang <jszhang@marvell.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: John Dias <joaodias@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12prctl: remove one-shot limitation for changing exe linkStanislav Kinsburskiy1-10/+0
This limitation came with the reason to remove "another way for malicious code to obscure a compromised program and masquerade as a benign process" by allowing "security-concious program can use this prctl once during its early initialization to ensure the prctl cannot later be abused for this purpose": http://marc.info/?l=linux-kernel&m=133160684517468&w=2 This explanation doesn't look sufficient. The only thing "exe" link is indicating is the file, used to execve, which is basically nothing and not reliable immediately after process has returned from execve system call. Moreover, to use this feture, all the mappings to previous exe file have to be unmapped and all the new exe file permissions must be satisfied. Which means, that changing exe link is very similar to calling execve on the binary. The need to remove this limitations comes from migration of NFS mount point, which is not accessible during restore and replaced by other file system. Because of this exe link has to be changed twice. [akpm@linux-foundation.org: fix up comment] Link: http://lkml.kernel.org/r/20160927153755.9337.69650.stgit@localhost.localdomain Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: John Stultz <john.stultz@linaro.org> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12kthread: add __printf attributesNicolas Iooss1-2/+3
When commit fbae2d44aa1d ("kthread: add kthread_create_worker*()") introduced some kthread_create_...() functions which were taking printf-like parametter, it introduced __printf attributes to some functions (e.g. kthread_create_worker()). Nevertheless some new functions were forgotten (they have been detected thanks to -Wmissing-format-attribute warning flag). Add the missing __printf attributes to the newly-introduced functions in order to detect formatting issues at build-time with -Wformat flag. Link: http://lkml.kernel.org/r/20161126193543.22672-1-nicolas.iooss_linux@m4x.org Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-7/+0
Pull x86 asm updates from Ingo Molnar: "The main changes in this development cycle were: - a large number of call stack dumping/printing improvements: higher robustness, better cross-context dumping, improved output, etc. (Josh Poimboeuf) - vDSO getcpu() performance improvement for future Intel CPUs with the RDPID instruction (Andy Lutomirski) - add two new Intel AVX512 features and the CPUID support infrastructure for it: AVX512IFMA and AVX512VBMI. (Gayatri Kammela, He Chen) - more copy-user unification (Borislav Petkov) - entry code assembly macro simplifications (Alexander Kuleshov) - vDSO C/R support improvements (Dmitry Safonov) - misc fixes and cleanups (Borislav Petkov, Paul Bolle)" * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) scripts/decode_stacktrace.sh: Fix address line detection on x86 x86/boot/64: Use defines for page size x86/dumpstack: Make stack name tags more comprehensible selftests/x86: Add test_vdso to test getcpu() x86/vdso: Use RDPID in preference to LSL when available x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl() x86/cpufeatures: Enable new AVX512 cpu features x86/cpuid: Provide get_scattered_cpuid_leaf() x86/cpuid: Cleanup cpuid_regs definitions x86/copy_user: Unify the code by removing the 64-bit asm _copy_*_user() variants x86/unwind: Ensure stack grows down x86/vdso: Set vDSO pointer only after success x86/prctl/uapi: Remove #ifdef for CHECKPOINT_RESTORE x86/unwind: Detect bad stack return address x86/dumpstack: Warn on stack recursion x86/unwind: Warn on bad frame pointer x86/decoder: Use stderr if insn sanity test fails x86/decoder: Use stdout if insn decoder test is successful mm/page_alloc: Remove kernel address exposure in free_reserved_area() x86/dumpstack: Remove raw stack dump ...
2016-12-12Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-1/+1
Pull hotplug API fix from Ingo Molnar: "Late breaking fix from the v4.9 cycle: fix a hotplug register/ unregister notifier API asymmetry bug that can cause kernel warnings (and worse) with certain Kconfig combinations" * 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: hotplug: Make register and unregister notifier API symmetric
2016-12-12Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds10-330/+669
Pull scheduler updates from Ingo Molnar: "The main scheduler changes in this cycle were: - support Intel Turbo Boost Max Technology 3.0 (TBM3) by introducig a notion of 'better cores', which the scheduler will prefer to schedule single threaded workloads on. (Tim Chen, Srinivas Pandruvada) - enhance the handling of asymmetric capacity CPUs further (Morten Rasmussen) - improve/fix load handling when moving tasks between task groups (Vincent Guittot) - simplify and clean up the cputime code (Stanislaw Gruszka) - improve mass fork()ed task spread a.k.a. hackbench speedup (Vincent Guittot) - make struct kthread kmalloc()ed and related fixes (Oleg Nesterov) - add uaccess atomicity debugging (when using access_ok() in the wrong context), under CONFIG_DEBUG_ATOMIC_SLEEP=y (Peter Zijlstra) - implement various fixes, cleanups and other enhancements (Daniel Bristot de Oliveira, Martin Schwidefsky, Rafael J. Wysocki)" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) sched/core: Use load_avg for selecting idlest group sched/core: Fix find_idlest_group() for fork kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker() kthread: Don't use to_live_kthread() in kthread_[un]park() kthread: Don't use to_live_kthread() in kthread_stop() Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function" kthread: Make struct kthread kmalloc'ed x86/uaccess, sched/preempt: Verify access_ok() context sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO x86/sched: Use #include <linux/mutex.h> instead of #include <asm/mutex.h> cpufreq/intel_pstate: Use CPPC to get max performance acpi/bus: Set _OSC for diverse core support acpi/bus: Enable HWP CPPC objects x86/sched: Add SD_ASYM_PACKING flags to x86 ITMT CPU x86/sysctl: Add sysctl for ITMT scheduling feature x86: Enable Intel Turbo Boost Max Technology 3.0 x86/topology: Define x86's arch_update_cpu_topology sched: Extend scheduler's asym packing sched/fair: Clean up the tunable parameter definitions ...
2016-12-12Merge branches 'pm-sleep' and 'powercap'Rafael J. Wysocki3-31/+132
* pm-sleep: PM / sleep: Print active wakeup sources when blocking on wakeup_count reads x86/suspend: fix false positive KASAN warning on suspend/resume PM / sleep / ACPI: Use the ACPI_FADT_LOW_POWER_S0 flag PM / sleep: System sleep state selection interface rework PM / hibernate: Verify the consistent of e820 memory map by md5 digest * powercap: powercap / RAPL: Add Knights Mill CPUID powercap/intel_rapl: fix and tidy up error handling powercap/intel_rapl: Track active CPUs internally powercap/intel_rapl: Cleanup duplicated init code powercap/intel rapl: Convert to hotplug state machine powercap/intel_rapl: Propagate error code when registration fails powercap/intel_rapl: Add missing domain data update on hotplug
2016-12-12Merge branch 'pm-cpuidle'Rafael J. Wysocki3-67/+111
* pm-cpuidle: cpuidle: Add a kerneldoc comment to cpuidle_use_deepest_state() cpuidle: fix improper return value on error intel_idle: Convert to hotplug state machine intel_idle: Remove superfluous SMP fuction call MAINTAINERS: Add Jacob Pan as a new intel_idle maintainer MAINTAINERS: Add bug tracking system location entries for cpuidle x86/intel_idle: Add Knights Mill CPUID x86/intel_idle: Add CPU model 0x4a (Atom Z34xx series) thermal/intel_powerclamp: stop sched tick in forced idle thermal/intel_powerclamp: Convert to CPU hotplug state thermal/intel_powerclamp: Convert the kthread to kthread worker API thermal/intel_powerclamp: Remove duplicated code that starts the kthread sched/idle: Add support for tasks that inject idle cpuidle: Allow enforcing deepest idle state selection cpuidle/powernv: staticise powernv_idle_driver cpuidle: dt: assign ->enter_freeze to same as ->enter callback function cpuidle: governors: Remove remaining old module code
2016-12-12Merge branch 'pm-cpufreq'Rafael J. Wysocki1-20/+99
* pm-cpufreq: (51 commits) Documentation: intel_pstate: Document HWP energy/performance hints cpufreq: intel_pstate: Support for energy performance hints with HWP cpufreq: intel_pstate: Add locking around HWP requests cpufreq: ondemand: Set MIN_FREQUENCY_UP_THRESHOLD to 1 cpufreq: intel_pstate: Add Knights Mill CPUID MAINTAINERS: Add bug tracking system location entry for cpufreq cpufreq: dt: Add support for zx296718 cpufreq: acpi-cpufreq: drop rdmsr_on_cpus() usage cpufreq: acpi-cpufreq: Convert to hotplug state machine cpufreq: intel_pstate: fix intel_pstate_exit_perf_limits() prototype cpufreq: intel_pstate: Set EPP/EPB to 0 in performance mode cpufreq: schedutil: Rectify comment in sugov_irq_work() function cpufreq: intel_pstate: increase precision of performance limits cpufreq: intel_pstate: round up min_perf limits cpufreq: Make cpufreq_update_policy() void ACPI / processor: Make acpi_processor_ppc_has_changed() void cpufreq: Avoid using inactive policies cpufreq: intel_pstate: Generic governors support cpufreq: intel_pstate: Request P-states control from SMM if needed cpufreq: dt: Add support for r8a7743 and r8a7745 ...
2016-12-12Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds15-335/+400
Pull locking updates from Ingo Molnar: "The tree got pretty big in this development cycle, but the net effect is pretty good: 115 files changed, 673 insertions(+), 1522 deletions(-) The main changes were: - Rework and generalize the mutex code to remove per arch mutex primitives. (Peter Zijlstra) - Add vCPU preemption support: add an interface to query the preemption status of vCPUs and use it in locking primitives - this optimizes paravirt performance. (Pan Xinhui, Juergen Gross, Christian Borntraeger) - Introduce cpu_relax_yield() and remov cpu_relax_lowlatency() to clean up and improve the s390 lock yielding machinery and its core kernel impact. (Christian Borntraeger) - Micro-optimize mutexes some more. (Waiman Long) - Reluctantly add the to-be-deprecated mutex_trylock_recursive() interface on a temporary basis, to give the DRM code more time to get rid of its locking hacks. Any other users will be NAK-ed on sight. (We turned off the deprecation warning for the time being to not pollute the build log.) (Peter Zijlstra) - Improve the rtmutex code a bit, in light of recent long lived bugs/races. (Thomas Gleixner) - Misc fixes, cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/paravirt: Fix bool return type for PVOP_CALL() x86/paravirt: Fix native_patch() locking/ww_mutex: Use relaxed atomics locking/rtmutex: Explain locking rules for rt_mutex_proxy_unlock()/init_proxy_locked() locking/rtmutex: Get rid of RT_MUTEX_OWNER_MASKALL x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted() locking/mutex: Break out of expensive busy-loop on {mutex,rwsem}_spin_on_owner() when owner vCPU is preempted locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock() Documentation/virtual/kvm: Support the vCPU preemption check x86/xen: Support the vCPU preemption check x86/kvm: Support the vCPU preemption check x86/kvm: Support the vCPU preemption check kvm: Introduce kvm_write_guest_offset_cached() locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests locking/spinlocks, s390: Implement vcpu_is_preempted(cpu) locking/core, powerpc: Implement vcpu_is_preempted(cpu) sched/core: Introduce the vcpu_is_preempted(cpu) interface sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q locking/core: Provide common cpu_relax_yield() definition locking/mutex: Don't mark mutex_trylock_recursive() as deprecated, temporarily ...
2016-12-12Merge branch 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-6/+12
Pull SMP bootup updates from Ingo Molnar: "Three changes to unify/standardize some of the bootup message printing in kernel/smp.c between architectures" * 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kernel/smp: Tell the user we're bringing up secondary CPUs kernel/smp: Make the SMP boot message common on all arches kernel/smp: Define pr_fmt() for smp.c
2016-12-12Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds4-13/+28
Pull RCU updates from Ingo Molnar: "The main RCU changes in this development cycle were: - Miscellaneous fixes, including a change to call_rcu()'s rcu_head alignment check. - Security-motivated list consistency checks, which are disabled by default behind DEBUG_LIST. - Torture-test updates. - Documentation updates, yet again just simple changes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: torture: Prevent jitter from delaying build-only runs torture: Remove obsolete files from rcutorture .gitignore rcu: Don't kick unless grace period or request rcu: Make expedited grace periods recheck dyntick idle state torture: Trace long read-side delays rcu: RCU_TRACE enables event tracing as well as debugfs rcu: Remove obsolete comment from __call_rcu() rcu: Remove obsolete rcu_check_callbacks() header comment rcu: Tighten up __call_rcu() rcu_head alignment check Documentation/RCU: Fix minor typo documentation: Present updated RCU guarantee bug: Avoid Kconfig warning for BUG_ON_DATA_CORRUPTION lib/Kconfig.debug: Fix typo in select statement lkdtm: Add tests for struct list corruption bug: Provide toggle for BUG on data corruption list: Split list_del() debug checking into separate function rculist: Consolidate DEBUG_LIST for list_add_rcu() list: Split list_add() debug checking into separate function
2016-12-11sched/core: Use load_avg for selecting idlest groupVincent Guittot1-11/+44
find_idlest_group() only compares the runnable_load_avg when looking for the least loaded group. But on fork intensive use case like hackbench where tasks blocked quickly after the fork, this can lead to selecting the same CPU instead of other CPUs, which have similar runnable load but a lower load_avg. When the runnable_load_avg of 2 CPUs are close, we now take into account the amount of blocked load as a 2nd selection factor. There is now 3 zones for the runnable_load of the rq: - [0 .. (runnable_load - imbalance)]: Select the new rq which has significantly less runnable_load - [(runnable_load - imbalance) .. (runnable_load + imbalance)]: The runnable loads are close so we use load_avg to chose between the 2 rq - [(runnable_load + imbalance) .. ULONG_MAX]: Keep the current rq which has significantly less runnable_load The scale factor that is currently used for comparing runnable_load, doesn't work well with small value. As an example, the use of a scaling factor fails as soon as this_runnable_load == 0 because we always select local rq even if min_runnable_load is only 1, which doesn't really make sense because they are just the same. So instead of scaling factor, we use an absolute margin for runnable_load to detect CPUs with similar runnable_load and we keep using scaling factor for blocked load. For use case like hackbench, this enable the scheduler to select different CPUs during the fork sequence and to spread tasks across the system. Tests have been done on a Hikey board (ARM based octo cores) for several kernel. The result below gives min, max, avg and stdev values of 18 runs with each configuration. The patches depend on the "no missing update_rq_clock()" work. hackbench -P -g 1 ea86cb4b7621 7dc603c9028e v4.8 v4.8+patches min 0.049 0.050 0.051 0,048 avg 0.057 0.057(0%) 0.057(0%) 0,055(+5%) max 0.066 0.068 0.070 0,063 stdev +/-9% +/-9% +/-8% +/-9% More performance numbers here: https://lkml.kernel.org/r/20161203214707.GI20785@codeblueprint.co.uk Tested-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: kernellwp@gmail.com Cc: umgwanakikbuti@gmail.com Cc: yuyang.du@intel.comc Link: http://lkml.kernel.org/r/1481216215-24651-3-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11sched/core: Fix find_idlest_group() for forkVincent Guittot1-0/+8
During fork, the utilization of a task is init once the rq has been selected because the current utilization level of the rq is used to set the utilization of the fork task. As the task's utilization is still 0 at this step of the fork sequence, it doesn't make sense to look for some spare capacity that can fit the task's utilization. Furthermore, I can see perf regressions for the test: hackbench -P -g 1 because the least loaded policy is always bypassed and tasks are not spread during fork. With this patch and the fix below, we are back to same performances as for v4.8. The fix below is only a temporary one used for the test until a smarter solution is found because we can't simply remove the test which is useful for others benchmarks | @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t | | avg_cost = this_sd->avg_scan_cost; | | - /* | - * Due to large variance we need a large fuzz factor; hackbench in | - * particularly is sensitive here. | - */ | - if ((avg_idle / 512) < avg_cost) | - return -1; | - | time = local_clock(); | | for_each_cpu_wrap(cpu, sched_domain_span(sd), target, wrap) { Tested-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Acked-by: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: kernellwp@gmail.com Cc: umgwanakikbuti@gmail.com Cc: yuyang.du@intel.comc Link: http://lkml.kernel.org/r/1481216215-24651-2-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11Merge branch 'linus' into sched/core, to pick up fixesIngo Molnar8-64/+152
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11Merge branch 'linus' into locking/core, to pick up fixesIngo Molnar6-70/+80
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller6-70/+138
2016-12-09timekeeping: Use mul_u64_u32_shr() instead of open coding itThomas Gleixner1-21/+5
The resume code must deal with a clocksource delta which is potentially big enough to overflow the 64bit mult. Replace the open coded handling with the proper function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.921674404@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09timekeeping: Get rid of pointless typecastsThomas Gleixner1-3/+2
cycle_t is defined as u64, so casting it to u64 is a pointless and confusing exercise. cycle_t should simply go away and be replaced with a plain u64 to avoid further confusion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.844699737@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09timekeeping: Make the conversion call chain consistently unsignedThomas Gleixner1-13/+13
Propagating a unsigned value through signed variables and functions makes absolutely no sense and is just prone to (re)introduce subtle signed vs. unsigned issues as happened recently. Clean it up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.765843099@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversionThomas Gleixner1-2/+2
The clocksource delta to nanoseconds conversion is using signed math, but the delta is unsigned. This makes the conversion space smaller than necessary and in case of a multiplication overflow the conversion can become negative. The conversion is done with scaled math: s64 nsec_delta = ((s64)clkdelta * clk->mult) >> clk->shift; Shifting a signed integer right obvioulsy preserves the sign, which has interesting consequences: - Time jumps backwards - __iter_div_u64_rem() which is used in one of the calling code pathes will take forever to piecewise calculate the seconds/nanoseconds part. This has been reported by several people with different scenarios: David observed that when stopping a VM with a debugger: "It was essentially the stopped by debugger case. I forget exactly why, but the guest was being explicitly stopped from outside, it wasn't just scheduling lag. I think it was something in the vicinity of 10 minutes stopped." When lifting the stop the machine went dead. The stopped by debugger case is not really interesting, but nevertheless it would be a good thing not to die completely. But this was also observed on a live system by Liav: "When the OS is too overloaded, delta will get a high enough value for the msb of the sum delta * tkr->mult + tkr->xtime_nsec to be set, and so after the shift the nsec variable will gain a value similar to 0xffffffffff000000." Unfortunately this has been reintroduced recently with commit 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation"). It had been fixed a year ago already in commit 35a4933a8959 ("time: Avoid signed overflow in timekeeping_get_ns()"). Though it's not surprising that the issue has been reintroduced because the function itself and the whole call chain uses s64 for the result and the propagation of it. The change in this recent commit is subtle: s64 nsec; - nsec = (d * m + n) >> s: + nsec = d * m + n; + nsec >>= s; d being type of cycle_t adds another level of obfuscation. This wouldn't have happened if the previous change to unsigned computation would have made the 'nsec' variable u64 right away and a follow up patch had cleaned up the whole call chain. There have been patches submitted which basically did a revert of the above patch leaving everything else unchanged as signed. Back to square one. This spawned a admittedly pointless discussion about potential users which rely on the unsigned behaviour until someone pointed out that it had been fixed before. The changelogs of said patches added further confusion as they made finally false claims about the consequences for eventual users which expect signed results. Despite delta being cycle_t, aka. u64, it's very well possible to hand in a signed negative value and the signed computation will happily return the correct result. But nobody actually sat down and analyzed the code which was added as user after the propably unintended signed conversion. Though in sensitive code like this it's better to analyze it proper and make sure that nothing relies on this than hunting the subtle wreckage half a year later. After analyzing all call chains it stands that no caller can hand in a negative value (which actually would work due to the s64 cast) and rely on the signed math to do the right thing. Change the conversion function to unsigned math. The conversion of all call chains is done in a follow up patch. This solves the starvation issue, which was caused by the negative result, but it does not solve the underlying problem. It merily procrastinates it. When the timekeeper update is deferred long enough that the unsigned multiplication overflows, then time going backwards is observable again. It does neither solve the issue of clocksources with a small counter width which will wrap around possibly several times and cause random time stamps to be generated. But those are usually not found on systems used for virtualization, so this is likely a non issue. I took the liberty to claim authorship for this simply because analyzing all callsites and writing the changelog took substantially more time than just making the simple s/s64/u64/ change and ignore the rest. Fixes: 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation") Reported-by: David Gibson <david@gibson.dropbear.id.au> Reported-by: Liav Rehana <liavr@mellanox.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20161208204228.688545601@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08bpf: xdp: Allow head adjustment in XDP progMartin KaFai Lau3-2/+4
This patch allows XDP prog to extend/remove the packet data at the head (like adding or removing header). It is done by adding a new XDP helper bpf_xdp_adjust_head(). It also renames bpf_helper_changes_skb_data() to bpf_helper_changes_pkt_data() to better reflect that XDP prog does not work on skb. This patch adds one "xdp_adjust_head" bit to bpf_prog for the XDP-capable driver to check if the XDP prog requires bpf_xdp_adjust_head() support. The driver can then decide to error out during XDP_SETUP_PROG. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>