From: Tomoki Sekiyama Date: Mon, 28 May 2012 09:09:18 +0000 (+0900) Subject: x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs X-Git-Tag: Ubuntu-5.2.0-15.16~17829^2~4 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=f6175f5bfb4c9f2ed32758c95f765b529b1a7f15;p=mirror_ubuntu-eoan-kernel.git x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs In current Linux, percpu variable `vector_irq' is not cleared on offlined cpus while disabling devices' irqs. If the cpu that has the disabled irqs in vector_irq is hotplugged, __setup_vector_irq() hits invalid irq vector and may crash. This bug can be reproduced as following; # echo 0 > /sys/devices/system/cpu/cpu7/online # modprobe -r some_driver_using_interrupts # vector_irq@cpu7 uncleared # echo 1 > /sys/devices/system/cpu/cpu7/online # kernel may crash This patch fixes this bug by clearing vector_irq in __clear_irq_vector() even if the cpu is offlined. Signed-off-by: Tomoki Sekiyama Acked-by: Thomas Gleixner Cc: yrl.pp-manager.tt@hitachi.com Cc: ltc-kernel@ml.yrl.intra.hitachi.co.jp Cc: Suresh Siddha Cc: Yinghai Lu Cc: Alexander Gordeev Link: http://lkml.kernel.org/r/4FC340BE.7080101@hitachi.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index ac96561d1a99..5f0ff597437c 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1195,7 +1195,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) BUG_ON(!cfg->vector); vector = cfg->vector; - for_each_cpu_and(cpu, cfg->domain, cpu_online_mask) + for_each_cpu(cpu, cfg->domain) per_cpu(vector_irq, cpu)[vector] = -1; cfg->vector = 0; @@ -1203,7 +1203,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) if (likely(!cfg->move_in_progress)) return; - for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) { + for_each_cpu(cpu, cfg->old_domain) { for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { if (per_cpu(vector_irq, cpu)[vector] != irq)