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2015-08-22Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: "A series of small fixlets for a regression visible on OMAP devices caused by the conversion of the OMAP interrupt chips to hierarchical interrupt domains. Mostly one liners on the driver side plus a small helper function in the core to avoid open coded mess in the drivers" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/crossbar: Restore set_wake functionality irqchip/crossbar: Restore the mask on suspend behaviour ARM: OMAP: wakeupgen: Restore the irq_set_type() mechanism irqchip/crossbar: Restore the irq_set_type() mechanism genirq: Introduce irq_chip_set_type_parent() helper genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy
2015-08-22Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Thomas Gleixner: "Two minimalistic fixes for 4.2 regressions: - Eric fixed a thinko in the timer_list base switching code caused by the overhaul of the timer wheel. It can cause a cpu to see the wrong base for a timer while we move the timer around. - Guenter fixed a regression for IMX if booted w/o device tree, where the timer interrupt is not initialized and therefor the machine fails to boot" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource/imx: Fix boot with non-DT systems timer: Write timer->flags atomically
2015-08-19genirq: Introduce irq_chip_set_type_parent() helperGrygorii Strashko
This helper is required for irq chips which do not implement a irq_set_type callback and need to call down the irq domain hierarchy for the actual trigger type change. This helper is required to fix further wreckage caused by the conversion of TI OMAP to hierarchical irq domains and therefor tagged for stable. [ tglx: Massaged changelog ] Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: <linux@arm.linux.org.uk> Cc: <nsekhar@ti.com> Cc: <jason@lakedaemon.net> Cc: <balbi@ti.com> Cc: <linux-arm-kernel@lists.infradead.org> Cc: <tony@atomide.com> Cc: <marc.zyngier@arm.com> Cc: stable@vger.kernel.org # 4.1 Link: http://lkml.kernel.org/r/1439554830-19502-3-git-send-email-grygorii.strashko@ti.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-08-19genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchyGrygorii Strashko
irq_chip_retrigger_hierarchy() returns -ENOSYS if it was not able to find at least one .irq_retrigger() callback implemented in the IRQ domain hierarchy. That's wrong, because check_irq_resend() expects a 0 return value from the callback in case that the hardware assisted resend was not possible. If the return value is non zero the core code assumes hardware resend success and the software resend is not invoked. This results in lost interrupts on platforms where none of the parent irq chips in the hierarchy implements the retrigger callback. This is observable on TI OMAP, where the hierarchy is: ARM GIC <- OMAP wakeupgen <- TI Crossbar Return 0 instead so the software resend mechanism gets invoked. [ tglx: Massaged changelog ] Fixes: 85f08c17de26 ('genirq: Introduce helper functions...') Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: <linux@arm.linux.org.uk> Cc: <nsekhar@ti.com> Cc: <jason@lakedaemon.net> Cc: <balbi@ti.com> Cc: <linux-arm-kernel@lists.infradead.org> Cc: <tony@atomide.com> Cc: stable@vger.kernel.org # 4.1 Link: http://lkml.kernel.org/r/1439554830-19502-2-git-send-email-grygorii.strashko@ti.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-08-18timer: Write timer->flags atomicallyEric Dumazet
lock_timer_base() cannot prevent the following : CPU1 ( in __mod_timer() timer->flags |= TIMER_MIGRATING; spin_unlock(&base->lock); base = new_base; spin_lock(&base->lock); // The next line clears TIMER_MIGRATING timer->flags &= ~TIMER_BASEMASK; CPU2 (in lock_timer_base()) see timer base is cpu0 base spin_lock_irqsave(&base->lock, *flags); if (timer->flags == tf) return base; // oops, wrong base timer->flags |= base->cpu // too late We must write timer->flags in one go, otherwise we can fool other cpus. Fixes: bc7a34b8b9eb ("timer: Reduce timer migration overhead if disabled") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jon Christopherson <jon@jons.org> Cc: David Miller <davem@davemloft.net> Cc: xen-devel@lists.xen.org Cc: david.vrabel@citrix.com Cc: Sander Eikelenboom <linux@eikelenboom.it> Link: http://lkml.kernel.org/r/1439831928.32680.11.camel@edumazet-glaptop2.roam.corp.google.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de>
2015-08-17Merge branch 'for-4.2-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fix from Tejun Heo: "A fix for a subtle bug introduced back during 3.17 cycle which interferes with setting configurations under specific conditions" * 'for-4.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cpuset: use trialcs->mems_allowed as a temp variable
2015-08-14Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "Misc fixes: PMU driver corner cases, tooling fixes, and an 'AUX' (Intel PT) race related core fix" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel/cqm: Do not access cpu_data() from CPU_UP_PREPARE handler perf/x86/intel: Fix memory leak on hot-plug allocation fail perf: Fix PERF_EVENT_IOC_PERIOD migration race perf: Fix double-free of the AUX buffer perf: Fix fasync handling on inherited events perf tools: Fix test build error when bindir contains double slash perf stat: Fix transaction lenght metrics perf: Fix running time accounting
2015-08-14Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fix from Ingo Molnar: "A single fix for a locking self-test crash" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/pvqspinlock: Fix kernel panic in locking-selftest
2015-08-12perf: Fix PERF_EVENT_IOC_PERIOD migration racePeter Zijlstra
I ran the perf fuzzer, which triggered some WARN()s which are due to trying to stop/restart an event on the wrong CPU. Use the normal IPI pattern to ensure we run the code on the correct CPU. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: bad7192b842c ("perf: Fix PERF_EVENT_IOC_PERIOD to force-reset the period") Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12perf: Fix double-free of the AUX bufferBen Hutchings
If rb->aux_refcount is decremented to zero before rb->refcount, __rb_free_aux() may be called twice resulting in a double free of rb->aux_pages. Fix this by adding a check to __rb_free_aux(). Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 57ffc5ca679f ("perf: Fix AUX buffer refcounting") Link: http://lkml.kernel.org/r/1437953468.12842.17.camel@decadent.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-10cpuset: use trialcs->mems_allowed as a temp variableAlban Crequy
The comment says it's using trialcs->mems_allowed as a temp variable but it didn't match the code. Change the code to match the comment. This fixes an issue when writing in cpuset.mems when a sub-directory exists: we need to write several times for the information to persist: | root@alban:/sys/fs/cgroup/cpuset# mkdir footest9 | root@alban:/sys/fs/cgroup/cpuset# cd footest9 | root@alban:/sys/fs/cgroup/cpuset/footest9# mkdir aa | root@alban:/sys/fs/cgroup/cpuset/footest9# cat cpuset.mems | | root@alban:/sys/fs/cgroup/cpuset/footest9# echo 0 > cpuset.mems | root@alban:/sys/fs/cgroup/cpuset/footest9# cat cpuset.mems | | root@alban:/sys/fs/cgroup/cpuset/footest9# echo 0 > cpuset.mems | root@alban:/sys/fs/cgroup/cpuset/footest9# cat cpuset.mems | 0 | root@alban:/sys/fs/cgroup/cpuset/footest9# cat aa/cpuset.mems | | root@alban:/sys/fs/cgroup/cpuset/footest9# echo 0 > aa/cpuset.mems | root@alban:/sys/fs/cgroup/cpuset/footest9# cat aa/cpuset.mems | 0 | root@alban:/sys/fs/cgroup/cpuset/footest9# This should help to fix the following issue in Docker: https://github.com/opencontainers/runc/issues/133 In some conditions, a Docker container needs to be started twice in order to work. Signed-off-by: Alban Crequy <alban@endocode.com> Tested-by: Iago López Galeiras <iago@endocode.com> Cc: <stable@vger.kernel.org> # 3.17+ Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2015-08-07kthread: export kthread functionsDavid Kershner
The s-Par visornic driver, currently in staging, processes a queue being serviced by the an s-Par service partition. We can get a message that something has happened with the Service Partition, when that happens, we must not access the channel until we get a message that the service partition is back again. The visornic driver has a thread for processing the channel, when we get the message, we need to be able to park the thread and then resume it when the problem clears. We can do this with kthread_park and unpark but they are not exported from the kernel, this patch exports the needed functions. Signed-off-by: David Kershner <david.kershner@unisys.com> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Weinberger <richard.weinberger@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-07signal: fix information leak in copy_siginfo_to_userAmanieu d'Antras
This function may copy the si_addr_lsb, si_lower and si_upper fields to user mode when they haven't been initialized, which can leak kernel stack data to user mode. Just checking the value of si_code is insufficient because the same si_code value is shared between multiple signals. This is solved by checking the value of si_signo in addition to si_code. Signed-off-by: Amanieu d'Antras <amanieu@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-07signal: fix information leak in copy_siginfo_from_user32Amanieu d'Antras
This function can leak kernel stack data when the user siginfo_t has a positive si_code value. The top 16 bits of si_code descibe which fields in the siginfo_t union are active, but they are treated inconsistently between copy_siginfo_from_user32, copy_siginfo_to_user32 and copy_siginfo_to_user. copy_siginfo_from_user32 is called from rt_sigqueueinfo and rt_tgsigqueueinfo in which the user has full control overthe top 16 bits of si_code. This fixes the following information leaks: x86: 8 bytes leaked when sending a signal from a 32-bit process to itself. This leak grows to 16 bytes if the process uses x32. (si_code = __SI_CHLD) x86: 100 bytes leaked when sending a signal from a 32-bit process to a 64-bit process. (si_code = -1) sparc: 4 bytes leaked when sending a signal from a 32-bit process to a 64-bit process. (si_code = any) parsic and s390 have similar bugs, but they are not vulnerable because rt_[tg]sigqueueinfo have checks that prevent sending a positive si_code to a different process. These bugs are also fixed for consistency. Signed-off-by: Amanieu d'Antras <amanieu@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-04perf: Fix fasync handling on inherited eventsPeter Zijlstra
Vince reported that the fasync signal stuff doesn't work proper for inherited events. So fix that. Installing fasync allocates memory and sets filp->f_flags |= FASYNC, which upon the demise of the file descriptor ensures the allocation is freed and state is updated. Now for perf, we can have the events stick around for a while after the original FD is dead because of references from child events. So we cannot copy the fasync pointer around. We can however consistently use the parent's fasync, as that will be updated. Reported-and-Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Arnaldo Carvalho deMelo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: eranian@google.com Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-28module: weaken locking assertion for oops path.Rusty Russell
We don't actually hold the module_mutex when calling find_module_all from module_kallsyms_lookup_name: that's because it's used by the oops code and we don't want to deadlock. However, access to the list read-only is safe if preempt is disabled, so we can weaken the assertion. Keep a strong version for external callers though. Fixes: 0be964be0d45 ("module: Sanitize RCU usage and locking") Reported-by: He Kuang <hekuang@huawei.com> Cc: stable@kernel.org Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-07-27perf: Fix running time accountingPeter Zijlstra
A recent fix to the shadow timestamp inadvertly broke the running time accounting. We must not update the running timestamp if we fail to schedule the event, the event will not have ran. This can (and did) result in negative total runtime because the stopped timestamp was before the running timestamp (we 'started' but never stopped the event -- because it never really started we didn't have to stop it either). Reported-and-Tested-by: Vince Weaver <vincent.weaver@maine.edu> Fixes: 72f669c0086f ("perf: Update shadow timestamp before add event") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # 4.1 Cc: Shaohua Li <shli@fb.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-26Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "This update contains: - the manual revert of the SYSCALL32 changes which caused a regression - a fix for the MPX vma handling - three fixes for the ioremap 'is ram' checks. - PAT warning fixes - a trivial fix for the size calculation of TLB tracepoints - handle old EFI structures gracefully This also contains a PAT fix from Jan plus a revert thereof. Toshi explained why the code is correct" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/pat: Revert 'Adjust default caching mode translation tables' x86/asm/entry/32: Revert 'Do not use R9 in SYSCALL32' commit x86/mm: Fix newly introduced printk format warnings mm: Fix bugs in region_is_ram() x86/mm: Remove region_is_ram() call from ioremap x86/mm: Move warning from __ioremap_check_ram() to the call site x86/mm/pat, drivers/media/ivtv: Move the PAT warning and replace WARN() with pr_warn() x86/mm/pat, drivers/infiniband/ipath: Replace WARN() with pr_warn() x86/mm/pat: Adjust default caching mode translation tables x86/fpu: Disable dependent CPU features on "noxsave" x86/mpx: Do not set ->vm_ops on MPX VMAs x86/mm: Add parenthesis for TLB tracepoint size calculation efi: Handle memory error structures produced based on old versions of standard
2015-07-25Merge tag 'trace-v4.2-rc2-fix3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull ftrace fix from Steven Rostedt: "Back in 3.16 the ftrace code was redesigned and cleaned up to remove the double iteration list (one for registered ftrace ops, and one for registered "global" ops), to just use one list. That simplified the code but also broke the function tracing filtering on pid. This updates the code to handle the filtering again with the new logic" * tag 'trace-v4.2-rc2-fix3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Fix breakage of set_ftrace_pid
2015-07-24ftrace: Fix breakage of set_ftrace_pidSteven Rostedt (Red Hat)
Commit 4104d326b670 ("ftrace: Remove global function list and call function directly") simplified the ftrace code by removing the global_ops list with a new design. But this cleanup also broke the filtering of PIDs that are added to the set_ftrace_pid file. Add back the proper hooks to have pid filtering working once again. Cc: stable@vger.kernel.org # 3.16+ Reported-by: Matt Fleming <matt@console-pimps.org> Reported-by: Richard Weinberger <richard.weinberger@gmail.com> Tested-by: Matt Fleming <matt@console-pimps.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-07-22mm: Fix bugs in region_is_ram()Toshi Kani
region_is_ram() looks up the iomem_resource table to check if a target range is in RAM. However, it always returns with -1 due to invalid range checks. It always breaks the loop at the first entry of the table. Another issue is that it compares p->flags and flags, but it always fails. flags is declared as int, which makes it as a negative value with IORESOURCE_BUSY (0x80000000) set while p->flags is unsigned long. Fix the range check and flags so that region_is_ram() works as advertised. Signed-off-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Mike Travis <travis@sgi.com> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Roland Dreier <roland@purestorage.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1437088996-28511-4-git-send-email-toshi.kani@hp.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-21locking/pvqspinlock: Fix kernel panic in locking-selftestWaiman Long
Enabling locking-selftest in a VM guest may cause the following kernel panic: kernel BUG at .../kernel/locking/qspinlock_paravirt.h:137! This is due to the fact that the pvqspinlock unlock function is expecting either a _Q_LOCKED_VAL or _Q_SLOW_VAL in the lock byte. This patch prevents that bug report by ignoring it when debug_locks_silent is set. Otherwise, a warning will be printed if it contains an unexpected value. With this patch applied, the kernel locking-selftest completed without any noise. Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Waiman Long <Waiman.Long@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1436663959-53092-1-git-send-email-Waiman.Long@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-18Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Ingo Molnar: "Two families of fixes: - Fix an FPU context related boot crash on newer x86 hardware with larger context sizes than what most people test. To fix this without ugly kludges or extensive reverts we had to touch core task allocator, to allow x86 to determine the task size dynamically, at boot time. I've tested it on a number of x86 platforms, and I cross-built it to a handful of architectures: (warns) (warns) testing x86-64: -git: pass ( 0), -tip: pass ( 0) testing x86-32: -git: pass ( 0), -tip: pass ( 0) testing arm: -git: pass ( 1359), -tip: pass ( 1359) testing cris: -git: pass ( 1031), -tip: pass ( 1031) testing m32r: -git: pass ( 1135), -tip: pass ( 1135) testing m68k: -git: pass ( 1471), -tip: pass ( 1471) testing mips: -git: pass ( 1162), -tip: pass ( 1162) testing mn10300: -git: pass ( 1058), -tip: pass ( 1058) testing parisc: -git: pass ( 1846), -tip: pass ( 1846) testing sparc: -git: pass ( 1185), -tip: pass ( 1185) ... so I hope the cross-arch impact 'none', as intended. (by Dave Hansen) - Fix various NMI handling related bugs unearthed by the big asm code rewrite and generally make the NMI code more robust and more maintainable while at it. These changes are a bit late in the cycle, I hope they are still acceptable. (by Andy Lutomirski)" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86 x86/fpu, sched: Dynamically allocate 'struct fpu' x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code x86/nmi/64: Make the "NMI executing" variable more consistent x86/nmi/64: Minor asm simplification x86/nmi/64: Use DF to avoid userspace RSP confusing nested NMI detection x86/nmi/64: Reorder nested NMI checks x86/nmi/64: Improve nested NMI comments x86/nmi/64: Switch stacks on userspace NMI entry x86/nmi/64: Remove asm code that saves CR2 x86/nmi: Enable nested do_nmi() handling for 64-bit kernels
2015-07-18Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Ingo Molnar: "Fix for a misplaced export that can cause build failures in certain (rare) Kconfig situations" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick: Move the export of tick_broadcast_oneshot_control to the proper place
2015-07-18Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fix from Ingo Molnar: "A oneliner rq throttling fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Test list head instead of list entry in throttle_cfs_rq()
2015-07-18Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Ingo Molnar: "Misc irq fixes: - two driver fixes - a Xen regression fix - a nested irq thread crash fix" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gicv3-its: Fix mapping of LPIs to collections genirq: Prevent resend to interrupts marked IRQ_NESTED_THREAD genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for now gpio/davinci: Fix race in installing chained irq handler
2015-07-18x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it ↵Ingo Molnar
on x86 Don't burden architectures without dynamic task_struct sizing with the overhead of dynamic sizing. Also optimize the x86 code a bit by caching task_struct_size. Acked-and-Tested-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1437128892-9831-3-git-send-email-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-18x86/fpu, sched: Dynamically allocate 'struct fpu'Dave Hansen
The FPU rewrite removed the dynamic allocations of 'struct fpu'. But, this potentially wastes massive amounts of memory (2k per task on systems that do not have AVX-512 for instance). Instead of having a separate slab, this patch just appends the space that we need to the 'task_struct' which we dynamically allocate already. This saves from doing an extra slab allocation at fork(). The only real downside here is that we have to stick everything and the end of the task_struct. But, I think the BUILD_BUG_ON()s I stuck in there should keep that from being too fragile. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1437128892-9831-2-git-send-email-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-17genirq: Prevent resend to interrupts marked IRQ_NESTED_THREADThomas Gleixner
The resend mechanism happily calls the interrupt handler of interrupts which are marked IRQ_NESTED_THREAD from softirq context. This can result in crashes because the interrupt handler is not the proper way to invoke the device handlers. They must be invoked via handle_nested_irq. Prevent the resend even if the interrupt has no valid parent irq set. Its better to have a lost interrupt than a crashing machine. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
2015-07-15Merge tag 'trace-v4.2-rc1-fix' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fix from Steven Rostedt: "Fengguang Wu discovered a crash that happened to be because of the branch tracer (traces unlikely and likely branches) when enabled with certain debug options. What happened was that various debug options like lockdep and DEBUG_PREEMPT can cause parts of the branch tracer to recurse outside its recursion protection. In fact, part of its recursion protection used these features that caused the lockup. This cleans up the code a little and makes the recursion protection a bit more robust" * tag 'trace-v4.2-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Have branch tracer use recursive field of task struct
2015-07-15genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for nowThomas Gleixner
Boris reported that the sparse_irq protection around __cpu_up() in the generic code causes a regression on Xen. Xen allocates interrupts and some more in the xen_cpu_up() function, so it deadlocks on the sparse_irq_lock. There is no simple fix for this and we really should have the protection for all architectures, but for now the only solution is to move it to x86 where actual wreckage due to the lack of protection has been observed. Reported-and-tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Fixes: a89941816726 'hotplug: Prevent alloc/free of irq descriptors during cpu up/down' Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: xiao jin <jin.xiao@intel.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Borislav Petkov <bp@suse.de> Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com> Cc: xen-devel <xen-devel@lists.xenproject.org>
2015-07-14tick: Move the export of tick_broadcast_oneshot_control to the proper placeThomas Gleixner
tick_broadcast_oneshot_control got moved from tick-broadcast to tick-common, but the export stayed in the old place. Fix it up. Fixes: f32dd1170511 'tick/broadcast: Make idle check independent from mode and config' Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-12Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Thomas Gleixner: "This update from the timer departement contains: - A series of patches which address a shortcoming in the tick broadcast code. If the broadcast device is not available or an hrtimer emulated broadcast device, some of the original assumptions lead to boot failures. I rather plugged all of the corner cases instead of only addressing the issue reported, so the change got a little larger. Has been extensivly tested on x86 and arm. - Get rid of the last holdouts using do_posix_clock_monotonic_gettime() - A regression fix for the imx clocksource driver - An update to the new state callbacks mechanism for clockevents. This is required to simplify the conversion, which will take place in 4.3" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/broadcast: Prevent NULL pointer dereference time: Get rid of do_posix_clock_monotonic_gettime cris: Replace do_posix_clock_monotonic_gettime() tick/broadcast: Unbreak CONFIG_GENERIC_CLOCKEVENTS=n build tick/broadcast: Handle spurious interrupts gracefully tick/broadcast: Check for hrtimer broadcast active early tick/broadcast: Return busy when IPI is pending tick/broadcast: Return busy if periodic mode and hrtimer broadcast tick/broadcast: Move the check for periodic mode inside state handling tick/broadcast: Prevent deep idle if no broadcast device available tick/broadcast: Make idle check independent from mode and config tick/broadcast: Sanity check the shutdown of the local clock_event tick/broadcast: Prevent hrtimer recursion clockevents: Allow set-state callbacks to be optional clocksource/imx: Define clocksource for mx27
2015-07-12Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fix from Thomas Gleixner: "A single fix for a cpu hotplug race vs. interrupt descriptors: Prevent irq setup/teardown across the cpu starting/dying parts of cpu hotplug so that the starting/dying cpu has a stable view of the descriptor space. This has been an issue for all architectures in the cpu dying phase, where interrupts are migrated away from the dying cpu. In the starting phase its mostly a x86 issue vs the vector space update" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: hotplug: Prevent alloc/free of irq descriptors during cpu up/down
2015-07-11tick/broadcast: Prevent NULL pointer dereferenceThomas Gleixner
Dan reported that the recent changes to the broadcast code introduced a potential NULL dereference. Add the proper check. Fixes: e0454311903d "tick/broadcast: Sanity check the shutdown of the local clock_event" Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-08module: Fix load_module() error pathPeter Zijlstra
The load_module() error path frees a module but forgot to take it out of the mod_tree, leaving a dangling entry in the tree, causing havoc. Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reported-by: Arthur Marsh <arthur.marsh@internode.on.net> Tested-by: Arthur Marsh <arthur.marsh@internode.on.net> Fixes: 93c2e105f6bc ("module: Optimize __module_address() using a latched RB-tree") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-07-08Fix broken audit tests for exec arg lenLinus Torvalds
The "fix" in commit 0b08c5e5944 ("audit: Fix check of return value of strnlen_user()") didn't fix anything, it broke things. As reported by Steven Rostedt: "Yes, strnlen_user() returns 0 on fault, but if you look at what len is set to, than you would notice that on fault len would be -1" because we just subtracted one from the return value. So testing against 0 doesn't test for a fault condition, it tests against a perfectly valid empty string. Also fix up the usual braindamage wrt using WARN_ON() inside a conditional - make it part of the conditional and remove the explicit unlikely() (which is already part of the WARN_ON*() logic, exactly so that you don't have to write unreadable code. Reported-and-tested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Paul Moore <pmoore@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-08tracing: Have branch tracer use recursive field of task structSteven Rostedt (Red Hat)
Fengguang Wu's tests triggered a bug in the branch tracer's start up test when CONFIG_DEBUG_PREEMPT set. This was because that config adds some debug logic in the per cpu field, which calls back into the branch tracer. The branch tracer has its own recursive checks, but uses a per cpu variable to implement it. If retrieving the per cpu variable calls back into the branch tracer, you can see how things will break. Instead of using a per cpu variable, use the trace_recursion field of the current task struct. Simply set a bit when entering the branch tracing and clear it when leaving. If the bit is set on entry, just don't do the tracing. There's also the case with lockdep, as the local_irq_save() called before the recursion can also trigger code that can call back into the function. Changing that to a raw_local_irq_save() will protect that as well. This prevents the recursion and the inevitable crash that follows. Link: http://lkml.kernel.org/r/20150630141803.GA28071@wfg-t540p.sh.intel.com Cc: stable@vger.kernel.org # 3.10+ Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-07-08hotplug: Prevent alloc/free of irq descriptors during cpu up/downThomas Gleixner
When a cpu goes up some architectures (e.g. x86) have to walk the irq space to set up the vector space for the cpu. While this needs extra protection at the architecture level we can avoid a few race conditions by preventing the concurrent allocation/free of irq descriptors and the associated data. When a cpu goes down it moves the interrupts which are targeted to this cpu away by reassigning the affinities. While this happens interrupts can be allocated and freed, which opens a can of race conditions in the code which reassignes the affinities because interrupt descriptors might be freed underneath. Example: CPU1 CPU2 cpu_up/down irq_desc = irq_to_desc(irq); remove_from_radix_tree(desc); raw_spin_lock(&desc->lock); free(desc); We could protect the irq descriptors with RCU, but that would require a full tree change of all accesses to interrupt descriptors. But fortunately these kind of race conditions are rather limited to a few things like cpu hotplug. The normal setup/teardown is very well serialized. So the simpler and obvious solution is: Prevent allocation and freeing of interrupt descriptors accross cpu hotplug. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: xiao jin <jin.xiao@intel.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Borislav Petkov <bp@suse.de> Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com> Link: http://lkml.kernel.org/r/20150705171102.063519515@linutronix.de
2015-07-07tick/broadcast: Handle spurious interrupts gracefullyThomas Gleixner
Andriy reported that on a virtual machine the warning about negative expiry time in the clock events programming code triggered: hpet: hpet0 irq 40 for MSI hpet: hpet1 irq 41 for MSI Switching to clocksource hpet WARNING: at kernel/time/clockevents.c:239 [<ffffffff810ce6eb>] clockevents_program_event+0xdb/0xf0 [<ffffffff810cf211>] tick_handle_periodic_broadcast+0x41/0x50 [<ffffffff81016525>] timer_interrupt+0x15/0x20 When the second hpet is installed as a per cpu timer the broadcast event is not longer required and stopped, which sets the next_evt of the broadcast device to KTIME_MAX. If after that a spurious interrupt happens on the broadcast device, then the current code blindly handles it and tries to reprogram the broadcast device afterwards, which adds the period to next_evt. KTIME_MAX + period results in a negative expiry value causing the WARN_ON in the clockevents code to trigger. Add a proper check for the state of the broadcast device into the interrupt handler and return if the interrupt is spurious. [ Folded in pointer fix from Sudeep ] Reported-by: Andriy Gapon <avg@FreeBSD.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20150705205221.802094647@linutronix.de
2015-07-07tick/broadcast: Check for hrtimer broadcast active earlyThomas Gleixner
If the current cpu is the one which has the hrtimer based broadcast queued then we better return busy immediately instead of going through loops and hoops to figure that out. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Return busy when IPI is pendingThomas Gleixner
Tell the idle code not to go deep if the broadcast IPI is about to arrive. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Return busy if periodic mode and hrtimer broadcastThomas Gleixner
If the system is in periodic mode and the broadcast device is hrtimer based, return busy as we have no proper handling for this. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Move the check for periodic mode inside state handlingThomas Gleixner
We need to check more than the periodic mode for proper operation in all runtime combinations. To avoid code duplication move the check into the enter state handling. No functional change. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Prevent deep idle if no broadcast device availableThomas Gleixner
Add a check for a installed broadcast device to the oneshot control function and return busy if not. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Make idle check independent from mode and configThomas Gleixner
Currently the broadcast busy check, which prevents the idle code from going into deep idle, works only in one shot mode. If NOHZ and HIGHRES are off (config or command line) there is no sanity check at all, so under certain conditions cpus are allowed to go into deep idle, where the local timer stops, and are not woken up again because there is no broadcast timer installed or a hrtimer based broadcast device is not evaluated. Move tick_broadcast_oneshot_control() into the common code and provide proper subfunctions for the various config combinations. The common check in tick_broadcast_oneshot_control() is for the C3STOP misfeature flag of the local clock event device. If its not set, idle can proceed. If set, further checks are necessary. Provide checks for the trivial cases: - If broadcast is disabled in the config, then return busy - If oneshot mode (NOHZ/HIGHES) is disabled in the config, return busy if the broadcast device is hrtimer based. - If oneshot mode is enabled in the config call the original tick_broadcast_oneshot_control() function. That function needs extra checks which will be implemented in seperate patches. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Sanity check the shutdown of the local clock_eventThomas Gleixner
The broadcast code shuts down the local clock event unconditionally even if no broadcast device is installed or if the broadcast device is hrtimer based. Add proper sanity checks. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Prevent hrtimer recursionThomas Gleixner
The hrtimer based broadcast vehicle can cause a hrtimer recursion which went unnoticed until we changed the hrtimer expiry code to keep track of the currently running timer. local_timer_interrupt() local_handler() hrtimer_interrupt() expire_hrtimers() broadcast_hrtimer() send_ipis() local_handler() hrtimer_interrupt() .... Solution is simple: Prevent the local handler call from the broadcast code when the broadcast 'device' is hrtimer based. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07clockevents: Allow set-state callbacks to be optionalViresh Kumar
Its mandatory for the drivers to provide set_state_{oneshot|periodic}() (only if related modes are supported) and set_state_shutdown() callbacks today, if they are implementing the new set-state interface. But this leads to unnecessary noop callbacks for drivers which don't want to implement them. Over that, it will lead to a full function call for nothing really useful. Lets make all set-state callbacks optional. Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: http://lkml.kernel.org/r/1436256875-15562-1-git-send-email-daniel.lezcano@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-06sched/fair: Test list head instead of list entry in throttle_cfs_rq()Cong Wang
According to the comments, we need to test if this is the first throttled task, however, list_empty() tests on the entry cfs_rq->throttled_list, not the head, this is wrong. This is a bug because we don't re-init the list entry after removing it from the list, so list_empty() could return false even if the list is really empty. Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1435174907-432-1-git-send-email-xiyou.wangcong@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>