Commit e1fb96e0 authored Jun 04, 2015 by Huacai Chen Committed by Ralf Baechle Jun 06, 2015

MIPS: Loongson-3: Fix a cpu-hotplug issue in loongson3_ipi_interrupt()



setup_per_cpu_areas() only setup __per_cpu_offset[] for each possible
cpu, but loongson_sysconf.nr_cpus can be greater than possible cpus
(due to reserved_cpus_mask). So in loongson3_ipi_interrupt(), percpu
access will touch the original varible in .data..percpu section which
has been freed. Without this patch, cpu-hotplug will cause memery
corruption.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/10524/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

parent 5f35b9cd

arch/mips/loongson/loongson-3/smp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -272,7 +272,7 @@ void loongson3_ipi_interrupt(struct pt_regs *regs)
		if (action & SMP_ASK_C0COUNT) {
		BUG_ON(cpu != 0);
		c0count = read_c0_count();
		for (i = 1; i < loongson_sysconf.nr_cpus; i++)
		for (i = 1; i < num_possible_cpus(); i++)
		per_cpu(core0_c0count, i) = c0count;
		}
		}