• Paul Burton's avatar
    irqchip/mips-gic: Don't overrun pcpu_masks array · 91951f98
    Paul Burton authored
    Commit 2a078705 ("irqchip/mips-gic: Use gic_vpes instead of
    NR_CPUS") & commit 78930f09 ("irqchip/mips-gic: Clear percpu_masks
    correctly when mapping") both introduce code which accesses gic_vpes
    entries in the pcpu_masks array. However, this array has length NR_CPUS.
    If NR_CPUS is less than gic_vpes (ie. the kernel supports use of less
    CPUs than are present in the system) then we overrun the array, clobber
    some other data & generally die pretty promptly.
    
    Most notably this affects uniprocessor kernels running on any multicore
    or multithreaded Malta with a GIC (ie. the vast majority of real Malta
    boards).
    
    Fix this by only accessing up to min(gic_vpes, NR_CPUS) entries in the
    pcpu_masks array, preventing the array overrun.
    
    Fixes: 2a078705 ("irqchip/mips-gic: Use gic_vpes instead of NR_CPUS")
    Fixes: 78930f09 ("irqchip/mips-gic: Clear percpu_masks correctly when mapping")
    Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
    Cc: linux-mips@linux-mips.org
    Cc: Jason Cooper <jason@lakedaemon.net>
    Cc: Marc Zyngier <marc.zyngier@arm.com>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Link: http://lkml.kernel.org/r/1461234714-9975-1-git-send-email-paul.burton@imgtec.comSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    91951f98
irq-mips-gic.c 27 KB