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c622a3c21e
Found by syzkaller: BUG: unable to handle kernel NULL pointer dereference at 0000000000000120 IP: [<ffffffffa0797202>] kvm_irq_map_gsi+0x12/0x90 [kvm] PGD 6f80b067 PUD b6535067 PMD 0 Oops: 0000 [#1] SMP CPU: 3 PID: 4988 Comm: a.out Not tainted 4.4.9-300.fc23.x86_64 #1 [...] Call Trace: [<ffffffffa0795f62>] irqfd_update+0x32/0xc0 [kvm] [<ffffffffa0796c7c>] kvm_irqfd+0x3dc/0x5b0 [kvm] [<ffffffffa07943f4>] kvm_vm_ioctl+0x164/0x6f0 [kvm] [<ffffffff81241648>] do_vfs_ioctl+0x298/0x480 [<ffffffff812418a9>] SyS_ioctl+0x79/0x90 [<ffffffff817a1062>] tracesys_phase2+0x84/0x89 Code: b5 71 a7 e0 5b 41 5c 41 5d 5d f3 c3 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 8b 8f 10 2e 00 00 31 c0 48 89 e5 <39> 91 20 01 00 00 76 6a 48 63 d2 48 8b 94 d1 28 01 00 00 48 85 RIP [<ffffffffa0797202>] kvm_irq_map_gsi+0x12/0x90 [kvm] RSP <ffff8800926cbca8> CR2: 0000000000000120 Testcase: #include <unistd.h> #include <sys/syscall.h> #include <string.h> #include <stdint.h> #include <linux/kvm.h> #include <fcntl.h> #include <sys/ioctl.h> long r[26]; int main() { memset(r, -1, sizeof(r)); r[2] = open("/dev/kvm", 0); r[3] = ioctl(r[2], KVM_CREATE_VM, 0); struct kvm_irqfd ifd; ifd.fd = syscall(SYS_eventfd2, 5, 0); ifd.gsi = 3; ifd.flags = 2; ifd.resamplefd = ifd.fd; r[25] = ioctl(r[3], KVM_IRQFD, &ifd); return 0; } Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
241 lines
5.8 KiB
C
241 lines
5.8 KiB
C
/*
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* irqchip.c: Common API for in kernel interrupt controllers
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* Copyright (c) 2007, Intel Corporation.
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* Copyright 2010 Red Hat, Inc. and/or its affiliates.
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* Copyright (c) 2013, Alexander Graf <agraf@suse.de>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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*
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* This file is derived from virt/kvm/irq_comm.c.
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*
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* Authors:
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* Yaozu (Eddie) Dong <Eddie.dong@intel.com>
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* Alexander Graf <agraf@suse.de>
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*/
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#include <linux/kvm_host.h>
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#include <linux/slab.h>
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#include <linux/srcu.h>
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#include <linux/export.h>
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#include <trace/events/kvm.h>
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#include "irq.h"
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int kvm_irq_map_gsi(struct kvm *kvm,
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struct kvm_kernel_irq_routing_entry *entries, int gsi)
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{
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struct kvm_irq_routing_table *irq_rt;
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struct kvm_kernel_irq_routing_entry *e;
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int n = 0;
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irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
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lockdep_is_held(&kvm->irq_lock));
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if (irq_rt && gsi < irq_rt->nr_rt_entries) {
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hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
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entries[n] = *e;
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++n;
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}
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}
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return n;
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}
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int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
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{
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struct kvm_irq_routing_table *irq_rt;
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irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
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return irq_rt->chip[irqchip][pin];
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}
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int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
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{
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struct kvm_kernel_irq_routing_entry route;
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if (!irqchip_in_kernel(kvm) || msi->flags != 0)
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return -EINVAL;
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route.msi.address_lo = msi->address_lo;
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route.msi.address_hi = msi->address_hi;
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route.msi.data = msi->data;
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return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
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}
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/*
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* Return value:
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* < 0 Interrupt was ignored (masked or not delivered for other reasons)
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* = 0 Interrupt was coalesced (previous irq is still pending)
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* > 0 Number of CPUs interrupt was delivered to
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*/
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int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
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bool line_status)
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{
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struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
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int ret = -1, i, idx;
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trace_kvm_set_irq(irq, level, irq_source_id);
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/* Not possible to detect if the guest uses the PIC or the
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* IOAPIC. So set the bit in both. The guest will ignore
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* writes to the unused one.
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*/
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idx = srcu_read_lock(&kvm->irq_srcu);
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i = kvm_irq_map_gsi(kvm, irq_set, irq);
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srcu_read_unlock(&kvm->irq_srcu, idx);
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while (i--) {
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int r;
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r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
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line_status);
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if (r < 0)
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continue;
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ret = r + ((ret < 0) ? 0 : ret);
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}
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return ret;
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}
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static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
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{
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int i;
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if (!rt)
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return;
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for (i = 0; i < rt->nr_rt_entries; ++i) {
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struct kvm_kernel_irq_routing_entry *e;
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struct hlist_node *n;
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hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
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hlist_del(&e->link);
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kfree(e);
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}
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}
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kfree(rt);
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}
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void kvm_free_irq_routing(struct kvm *kvm)
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{
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/* Called only during vm destruction. Nobody can use the pointer
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at this stage */
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struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
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free_irq_routing_table(rt);
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}
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static int setup_routing_entry(struct kvm_irq_routing_table *rt,
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struct kvm_kernel_irq_routing_entry *e,
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const struct kvm_irq_routing_entry *ue)
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{
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int r = -EINVAL;
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struct kvm_kernel_irq_routing_entry *ei;
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/*
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* Do not allow GSI to be mapped to the same irqchip more than once.
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* Allow only one to one mapping between GSI and non-irqchip routing.
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*/
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hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
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if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
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ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
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ue->u.irqchip.irqchip == ei->irqchip.irqchip)
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return r;
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e->gsi = ue->gsi;
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e->type = ue->type;
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r = kvm_set_routing_entry(e, ue);
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if (r)
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goto out;
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if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
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rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
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hlist_add_head(&e->link, &rt->map[e->gsi]);
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r = 0;
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out:
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return r;
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}
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void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
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{
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}
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int kvm_set_irq_routing(struct kvm *kvm,
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const struct kvm_irq_routing_entry *ue,
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unsigned nr,
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unsigned flags)
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{
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struct kvm_irq_routing_table *new, *old;
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u32 i, j, nr_rt_entries = 0;
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int r;
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for (i = 0; i < nr; ++i) {
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if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
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return -EINVAL;
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nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
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}
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nr_rt_entries += 1;
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new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)),
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GFP_KERNEL);
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if (!new)
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return -ENOMEM;
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new->nr_rt_entries = nr_rt_entries;
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for (i = 0; i < KVM_NR_IRQCHIPS; i++)
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for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
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new->chip[i][j] = -1;
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for (i = 0; i < nr; ++i) {
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struct kvm_kernel_irq_routing_entry *e;
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r = -ENOMEM;
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e = kzalloc(sizeof(*e), GFP_KERNEL);
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if (!e)
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goto out;
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r = -EINVAL;
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if (ue->flags) {
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kfree(e);
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goto out;
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}
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r = setup_routing_entry(new, e, ue);
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if (r) {
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kfree(e);
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goto out;
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}
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++ue;
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}
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mutex_lock(&kvm->irq_lock);
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old = kvm->irq_routing;
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rcu_assign_pointer(kvm->irq_routing, new);
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kvm_irq_routing_update(kvm);
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kvm_arch_irq_routing_update(kvm);
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mutex_unlock(&kvm->irq_lock);
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kvm_arch_post_irq_routing_update(kvm);
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synchronize_srcu_expedited(&kvm->irq_srcu);
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new = old;
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r = 0;
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out:
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free_irq_routing_table(new);
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return r;
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}
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