commit f75d48644c56a31731d17fa693c8175328957e1d upstream. __clear_bit_unlock() is a special little snowflake. While it carries the non-atomic '__' prefix, it is specifically documented to pair with test_and_set_bit() and therefore should be 'somewhat' atomic. Therefore the generic implementation of __clear_bit_unlock() cannot use the fully non-atomic __clear_bit() as a default. If an arch is able to do better; is must provide an implementation of __clear_bit_unlock() itself. Specifically, this came up as a result of hackbench livelock'ing in slab_lock() on ARC with SMP + SLUB + !LLSC. The issue was incorrect pairing of atomic ops. slab_lock() -> bit_spin_lock() -> test_and_set_bit() slab_unlock() -> __bit_spin_unlock() -> __clear_bit() The non serializing __clear_bit() was getting "lost" 80543b8e: ld_s r2,[r13,0] <--- (A) Finds PG_locked is set 80543b90: or r3,r2,1 <--- (B) other core unlocks right here 80543b94: st_s r3,[r13,0] <--- (C) sets PG_locked (overwrites unlock) Fixes ARC STAR 9000817404 (and probably more). Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com> Tested-by: Vineet Gupta <Vineet.Gupta1@synopsys.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Helge Deller <deller@gmx.de> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Noam Camus <noamc@ezchip.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160309114054.GJ6356@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0f26922fe5dc5724b1adbbd54b21bad03590b4f3 upstream.
The datatype __kernel_time_t is u32 on 32bit platform, so its subject to
overflows in the timeval/timespec to cputime conversion.
Currently the following functions are affected:
1. setitimer()
2. timer_create/timer_settime()
3. sys_clock_nanosleep
This can happen on MIPS32 and ARM32 with "Full dynticks CPU time accounting"
enabled, which is required for CONFIG_NO_HZ_FULL.
Enforce u64 conversion to prevent the overflow.
Fixes: 31c1fc818715 ("ARM: Kconfig: allow full nohz CPU accounting")
Signed-off-by: zengtao <prime.zeng@huawei.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1454384314-154784-1-git-send-email-prime.zeng@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit fe32d3cd5e8eb0f82e459763374aa80797023403 upstream.
These functions check should_resched() before unlocking spinlock/bh-enable:
preempt_count always non-zero => should_resched() always returns false.
cond_resched_lock() worked iff spin_needbreak is set.
This patch adds argument "preempt_offset" to should_resched().
preempt_count offset constants for that:
PREEMPT_DISABLE_OFFSET - offset after preempt_disable()
PREEMPT_LOCK_OFFSET - offset after spin_lock()
SOFTIRQ_DISABLE_OFFSET - offset after local_bh_distable()
SOFTIRQ_LOCK_OFFSET - offset after spin_lock_bh()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers")
Link: http://lkml.kernel.org/r/20150715095204.12246.98268.stgit@buzz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ luis: backported to 3.16:
- some of the changes done in preempt_mask.h instead of preempt.h
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 7f8998c7aef3ac9c5f3f2943e083dfa6302e90d0 upstream.
The different architectures used their own (and different) declarations:
extern __visible const void __nosave_begin, __nosave_end;
extern const void __nosave_begin, __nosave_end;
extern long __nosave_begin, __nosave_end;
Consolidate them using the first variant in <asm/sections.h>.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
This fixes a typo that named the read_mostly section of percpu as readmostly. It works fine with SMP because the linker script specifies .data..percpu..readmostly. However, UP kernel builds don't have percpu sections defined and the non-percpu version of the section is called data..read_mostly, so .data..readmostly will float around and may break things unexpectedly. Looking at the original change that introduced data..percpu..readmostly (commit c957ef2c59e952803766ddc22e89981ab534606f), it looks like this was the original intention. Tested: Built UP kernel and confirmed the sections got merged. - Before the patch: $ objdump -h vmlinux.o | grep '\.data\.\.read.*mostly' 38 .data..read_mostly 00004418 0000000000000000 0000000000000000 00431ac0 2**6 50 .data..readmostly 00000014 0000000000000000 0000000000000000 00444000 2**3 - After the patch: $ objdump -h vmlinux.o | grep '\.data\.\.read.*mostly' 38 .data..read_mostly 00004438 0000000000000000 0000000000000000 00431ac0 2**6 Signed-off-by: Zhengyu He <hzy@google.com> Signed-off-by: Filipe Brandenburger <filbranden@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Pull more perf updates from Ingo Molnar:
"A second round of perf updates:
- wide reaching kprobes sanitization and robustization, with the hope
of fixing all 'probe this function crashes the kernel' bugs, by
Masami Hiramatsu.
- uprobes updates from Oleg Nesterov: tmpfs support, corner case
fixes and robustization work.
- perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
et al:
* Add support to accumulate hist periods (Namhyung Kim)
* various fixes, refactorings and enhancements"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
perf: Differentiate exec() and non-exec() comm events
perf: Fix perf_event_comm() vs. exec() assumption
uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
perf/documentation: Add description for conditional branch filter
perf/x86: Add conditional branch filtering support
perf/tool: Add conditional branch filter 'cond' to perf record
perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
uprobes: Teach copy_insn() to support tmpfs
uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
perf/x86: Use common PMU interrupt disabled code
perf/ARM: Use common PMU interrupt disabled code
perf: Disable sampled events if no PMU interrupt
perf: Fix use after free in perf_remove_from_context()
perf tools: Fix 'make help' message error
perf record: Fix poll return value propagation
perf tools: Move elide bool into perf_hpp_fmt struct
perf tools: Remove elide setup for SORT_MODE__MEMORY mode
perf tools: Fix "==" into "=" in ui_browser__warning assignment
perf tools: Allow overriding sysfs and proc finding with env var
perf tools: Consider header files outside perf directory in tags target
...
Pull more locking changes from Ingo Molnar: "This is the second round of locking tree updates for v3.16, offering large system scalability improvements: - optimistic spinning for rwsems, from Davidlohr Bueso. - 'qrwlocks' core code and x86 enablement, from Waiman Long and PeterZ" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, locking/rwlocks: Enable qrwlocks on x86 locking/rwlocks: Introduce 'qrwlocks' - fair, queued rwlocks locking/mutexes: Documentation update/rewrite locking/rwsem: Fix checkpatch.pl warnings locking/rwsem: Fix warnings for CONFIG_RWSEM_GENERIC_SPINLOCK locking/rwsem: Support optimistic spinning
When running sparse over drivers/media/v4l2-core/v4l2-ioctl.c I get these
errors:
drivers/media/v4l2-core/v4l2-ioctl.c:2043:9: error: bad integer constant expression
drivers/media/v4l2-core/v4l2-ioctl.c:2044:9: error: bad integer constant expression
drivers/media/v4l2-core/v4l2-ioctl.c:2045:9: error: bad integer constant expression
drivers/media/v4l2-core/v4l2-ioctl.c:2046:9: error: bad integer constant expression
etc.
The root cause of that turns out to be in include/asm-generic/ioctl.h:
#include <uapi/asm-generic/ioctl.h>
/* provoke compile error for invalid uses of size argument */
extern unsigned int __invalid_size_argument_for_IOC;
#define _IOC_TYPECHECK(t) \
((sizeof(t) == sizeof(t[1]) && \
sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
sizeof(t) : __invalid_size_argument_for_IOC)
If it is defined as this (as is already done if __KERNEL__ is not defined):
#define _IOC_TYPECHECK(t) (sizeof(t))
then all is well with the world.
This patch allows sparse to work correctly.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull arm64 updates from Catalin Marinas: - Optimised assembly string/memory routines (based on the AArch64 Cortex Strings library contributed to glibc but re-licensed under GPLv2) - Optimised crypto algorithms making use of the ARMv8 crypto extensions (together with kernel API for using FPSIMD instructions in interrupt context) - Ftrace support - CPU topology parsing from DT - ESR_EL1 (Exception Syndrome Register) exposed to user space signal handlers for SIGSEGV/SIGBUS (useful to emulation tools like Qemu) - 1GB section linear mapping if applicable - Barriers usage clean-up - Default pgprot clean-up Conflicts as per Catalin. * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (57 commits) arm64: kernel: initialize broadcast hrtimer based clock event device arm64: ftrace: Add system call tracepoint arm64: ftrace: Add CALLER_ADDRx macros arm64: ftrace: Add dynamic ftrace support arm64: Add ftrace support ftrace: Add arm64 support to recordmcount arm64: Add 'notrace' attribute to unwind_frame() for ftrace arm64: add __ASSEMBLY__ in asm/insn.h arm64: Fix linker script entry point arm64: lib: Implement optimized string length routines arm64: lib: Implement optimized string compare routines arm64: lib: Implement optimized memcmp routine arm64: lib: Implement optimized memset routine arm64: lib: Implement optimized memmove routine arm64: lib: Implement optimized memcpy routine arm64: defconfig: enable a few more common/useful options in defconfig ftrace: Make CALLER_ADDRx macros more generic arm64: Fix deadlock scenario with smp_send_stop() arm64: Fix machine_shutdown() definition arm64: Support arch_irq_work_raise() via self IPIs ...
This rwlock uses the arch_spin_lock_t as a waitqueue, and assuming the arch_spin_lock_t is a fair lock (ticket,mcs etc..) the resulting rwlock is a fair lock. It fits in the same 8 bytes as the regular rwlock_t by folding the reader and writer count into a single integer, using the remaining 4 bytes for the arch_spinlock_t. Architectures that can single-copy adress bytes can optimize queue_write_unlock() with a 0 write to the LSB (the write count). Performance as measured by Davidlohr Bueso (rwlock_t -> qrwlock_t): +--------------+-------------+---------------+ | Workload | #users | delta | +--------------+-------------+---------------+ | alltests | > 1400 | -4.83% | | custom | 0-100,> 100 | +1.43%,-1.57% | | high_systime | > 1000 | -2.61 | | shared | all | +0.32 | +--------------+-------------+---------------+ http://www.stgolabs.net/qrwlock-stuff/aim7-results-vs-rwsem_optsin/ Signed-off-by: Waiman Long <Waiman.Long@hp.com> [peterz: near complete rewrite] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Paul E.McKenney" <paulmck@linux.vnet.ibm.com> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-gac1nnl3wvs2ij87zv2xkdzq@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>