Commit-ID: 1d44b30f35a9873a65b320dd5300088fa995fd94 Gitweb: http://git.kernel.org/tip/1d44b30f35a9873a65b320dd5300088fa995fd94 Author: Tomoki Sekiyama <tomoki.sekiyama...@hitachi.com> AuthorDate: Thu, 26 Jul 2012 19:47:32 +0900 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 26 Jul 2012 15:01:17 +0200
x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs In the current kernel, percpu variable `vector_irq' is not always cleared when a CPU is offlined. If the CPU that has the disabled irqs in vector_irq is hotplugged again, __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 To fix this problem, this patch clears vector_irq in __fixup_irqs() when the CPU is offlined. This also reverts commit f6175f5bfb4c, which partially fixes this bug by clearing vector in __clear_irq_vector(). But in environments with IOMMU IRQ remapper, it could fail because cfg->domain doesn't contain offlined CPUs. With this patch, the fix in __clear_irq_vector() can be reverted because every vector_irq is already cleared in __fixup_irqs() on offlined CPUs. Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama...@hitachi.com> Acked-by: Suresh Siddha <suresh.b.sid...@intel.com> Cc: yrl.pp-manager...@hitachi.com Cc: Yinghai Lu <ying...@kernel.org> Cc: Alexander Gordeev <agord...@redhat.com> Link: http://lkml.kernel.org/r/20120726104732.2889.19144.stgit@kvmdev Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/apic/io_apic.c | 4 ++-- arch/x86/kernel/irq.c | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 406eee7..a6c64aa 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1204,7 +1204,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) BUG_ON(!cfg->vector); vector = cfg->vector; - for_each_cpu(cpu, cfg->domain) + for_each_cpu_and(cpu, cfg->domain, cpu_online_mask) per_cpu(vector_irq, cpu)[vector] = -1; cfg->vector = 0; @@ -1212,7 +1212,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) if (likely(!cfg->move_in_progress)) return; - for_each_cpu(cpu, cfg->old_domain) { + for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) { for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { if (per_cpu(vector_irq, cpu)[vector] != irq) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 1f5f1d5..7ad683d 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -328,6 +328,7 @@ void fixup_irqs(void) chip->irq_retrigger(data); raw_spin_unlock(&desc->lock); } + __this_cpu_write(vector_irq[vector], -1); } } #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
