e88d62cd4b
As raw_cpu_generic_read() is a plain read from a raw_cpu_ptr() address, it's possible (albeit unlikely) that the compiler will split the access across multiple instructions. In this_cpu_generic_read() we disable preemption but not interrupts before calling raw_cpu_generic_read(). Thus, an interrupt could be taken in the middle of the split load instructions. If a this_cpu_write() or RMW this_cpu_*() op is made to the same variable in the interrupt handling path, this_cpu_read() will return a torn value. For native word types, we can avoid tearing using READ_ONCE(), but this won't work in all cases (e.g. 64-bit types on most 32-bit platforms). This patch reworks this_cpu_generic_read() to use READ_ONCE() where possible, otherwise falling back to disabling interrupts. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Lameter <cl@linux.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org> |
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| .. | ||
| bitops | ||
| 4level-fixup.h | ||
| 5level-fixup.h | ||
| asm-offsets.h | ||
| asm-prototypes.h | ||
| atomic64.h | ||
| atomic-long.h | ||
| atomic.h | ||
| audit_change_attr.h | ||
| audit_dir_write.h | ||
| audit_read.h | ||
| audit_signal.h | ||
| audit_write.h | ||
| barrier.h | ||
| bitops.h | ||
| bitsperlong.h | ||
| bug.h | ||
| bugs.h | ||
| cache.h | ||
| cacheflush.h | ||
| checksum.h | ||
| clkdev.h | ||
| cmpxchg-local.h | ||
| cmpxchg.h | ||
| current.h | ||
| delay.h | ||
| device.h | ||
| div64.h | ||
| dma-contiguous.h | ||
| dma.h | ||
| early_ioremap.h | ||
| emergency-restart.h | ||
| exec.h | ||
| export.h | ||
| extable.h | ||
| fb.h | ||
| fixmap.h | ||
| ftrace.h | ||
| futex.h | ||
| getorder.h | ||
| gpio.h | ||
| hardirq.h | ||
| hugetlb.h | ||
| hw_irq.h | ||
| ide_iops.h | ||
| int-ll64.h | ||
| io.h | ||
| ioctl.h | ||
| iomap.h | ||
| irq_regs.h | ||
| irq_work.h | ||
| irq.h | ||
| irqflags.h | ||
| kdebug.h | ||
| kmap_types.h | ||
| kprobes.h | ||
| kvm_para.h | ||
| linkage.h | ||
| local64.h | ||
| local.h | ||
| mcs_spinlock.h | ||
| memory_model.h | ||
| mm_hooks.h | ||
| mm-arch-hooks.h | ||
| mmu_context.h | ||
| mmu.h | ||
| module.h | ||
| msi.h | ||
| page.h | ||
| param.h | ||
| parport.h | ||
| pci_iomap.h | ||
| pci.h | ||
| percpu.h | ||
| pgalloc.h | ||
| pgtable-nop4d-hack.h | ||
| pgtable-nop4d.h | ||
| pgtable-nopmd.h | ||
| pgtable-nopud.h | ||
| pgtable.h | ||
| preempt.h | ||
| ptrace.h | ||
| qrwlock_types.h | ||
| qrwlock.h | ||
| qspinlock_types.h | ||
| qspinlock.h | ||
| resource.h | ||
| rwsem.h | ||
| seccomp.h | ||
| sections.h | ||
| segment.h | ||
| serial.h | ||
| set_memory.h | ||
| signal.h | ||
| simd.h | ||
| sizes.h | ||
| spinlock.h | ||
| statfs.h | ||
| string.h | ||
| switch_to.h | ||
| syscall.h | ||
| syscalls.h | ||
| termios-base.h | ||
| termios.h | ||
| timex.h | ||
| tlb.h | ||
| tlbflush.h | ||
| topology.h | ||
| trace_clock.h | ||
| uaccess.h | ||
| unaligned.h | ||
| unistd.h | ||
| user.h | ||
| vga.h | ||
| vmlinux.lds.h | ||
| vtime.h | ||
| word-at-a-time.h | ||
| xor.h | ||