| Message ID | 1367938456-21005-1-git-send-email-asias@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 07, 2013 at 10:54:16PM +0800, Asias He wrote: > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > kvm_arch_init() will fail with -EEXIST, Wow. Is this intentional? > then kvm_irqfd_exit() will be > called on the error handling path. This way, the kvm_irqfd system will > not be ready. > > This patch fix the following: > > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > PGD 0 > Oops: 0002 [#1] SMP > Modules linked in: vhost_net > CPU 6 > Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK > RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 > RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 > RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 > RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 > R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 > R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 > FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) > Stack: > ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 > 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 > ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 > Call Trace: > [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 > [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 > [<ffffffff810ac949>] queue_work+0x19/0x20 > [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 > [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 > [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 > [<ffffffff810c9545>] ? update_curr+0xf5/0x180 > [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 > [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 > [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 > [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 > [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c > [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b > Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f > RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > RSP <ffff880221721cc8> > CR2: 0000000000000000 > ---[ end trace 13fb1e4b6e5ab21f ]--- > > Signed-off-by: Asias He <asias@redhat.com> > --- > virt/kvm/kvm_main.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 8fd325a..3c8a992 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3078,13 +3078,14 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, > int r; > int cpu; > > - r = kvm_irqfd_init(); > - if (r) > - goto out_irqfd; > r = kvm_arch_init(opaque); > if (r) > goto out_fail; > > + r = kvm_irqfd_init(); > + if (r) > + goto out_irqfd; > + > if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { > r = -ENOMEM; > goto out_free_0; > @@ -3159,10 +3160,10 @@ out_free_1: > out_free_0a: > free_cpumask_var(cpus_hardware_enabled); > out_free_0: > - kvm_arch_exit(); > -out_fail: > kvm_irqfd_exit(); > out_irqfd: > + kvm_arch_exit(); > +out_fail: > return r; > } > EXPORT_SYMBOL_GPL(kvm_init); > -- > 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, May 07, 2013 at 05:59:38PM +0300, Michael S. Tsirkin wrote: > On Tue, May 07, 2013 at 10:54:16PM +0800, Asias He wrote: > > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > > kvm_arch_init() will fail with -EEXIST, > > Wow. Is this intentional? I think it is. You can not be amd and intel at the same time ;-) kvm_arch_init if (kvm_x86_ops) { printk(KERN_ERR "kvm: already loaded the other module\n"); r = -EEXIST; goto out; } > > then kvm_irqfd_exit() will be > > called on the error handling path. This way, the kvm_irqfd system will > > not be ready. > > > > This patch fix the following: > > > > BUG: unable to handle kernel NULL pointer dereference at (null) > > IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > PGD 0 > > Oops: 0002 [#1] SMP > > Modules linked in: vhost_net > > CPU 6 > > Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK > > RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 > > RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 > > RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 > > RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 > > R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 > > R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 > > FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) > > Stack: > > ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 > > 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 > > ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 > > Call Trace: > > [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 > > [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 > > [<ffffffff810ac949>] queue_work+0x19/0x20 > > [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 > > [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 > > [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 > > [<ffffffff810c9545>] ? update_curr+0xf5/0x180 > > [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 > > [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 > > [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 > > [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 > > [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c > > [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b > > Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f > > RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > RSP <ffff880221721cc8> > > CR2: 0000000000000000 > > ---[ end trace 13fb1e4b6e5ab21f ]--- > > > > Signed-off-by: Asias He <asias@redhat.com> > > --- > > virt/kvm/kvm_main.c | 11 ++++++----- > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index 8fd325a..3c8a992 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -3078,13 +3078,14 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, > > int r; > > int cpu; > > > > - r = kvm_irqfd_init(); > > - if (r) > > - goto out_irqfd; > > r = kvm_arch_init(opaque); > > if (r) > > goto out_fail; > > > > + r = kvm_irqfd_init(); > > + if (r) > > + goto out_irqfd; > > + > > if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { > > r = -ENOMEM; > > goto out_free_0; > > @@ -3159,10 +3160,10 @@ out_free_1: > > out_free_0a: > > free_cpumask_var(cpus_hardware_enabled); > > out_free_0: > > - kvm_arch_exit(); > > -out_fail: > > kvm_irqfd_exit(); > > out_irqfd: > > + kvm_arch_exit(); > > +out_fail: > > return r; > > } > > EXPORT_SYMBOL_GPL(kvm_init); > > -- > > 1.8.1.4
On Tue, May 07, 2013 at 11:05:12PM +0800, Asias He wrote: > On Tue, May 07, 2013 at 05:59:38PM +0300, Michael S. Tsirkin wrote: > > On Tue, May 07, 2013 at 10:54:16PM +0800, Asias He wrote: > > > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > > > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > > > kvm_arch_init() will fail with -EEXIST, > > > > Wow. Is this intentional? > > I think it is. You can not be amd and intel at the same time ;-) > > kvm_arch_init > > if (kvm_x86_ops) { > printk(KERN_ERR "kvm: already loaded the other module\n"); > r = -EEXIST; > goto out; > } > Interesting. So we check it with if (kvm_x86_ops) and later we do kvm_x86_ops = ops; This looks racy - or is something serializing module loading? > > > called on the error handling path. This way, the kvm_irqfd system will > > > not be ready. > > > > > > This patch fix the following: > > > > > > BUG: unable to handle kernel NULL pointer dereference at (null) > > > IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > > PGD 0 > > > Oops: 0002 [#1] SMP > > > Modules linked in: vhost_net > > > CPU 6 > > > Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK > > > RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > > RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 > > > RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 > > > RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 > > > RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 > > > R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 > > > R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 > > > FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > > Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) > > > Stack: > > > ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 > > > 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 > > > ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 > > > Call Trace: > > > [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 > > > [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 > > > [<ffffffff810ac949>] queue_work+0x19/0x20 > > > [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 > > > [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 > > > [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 > > > [<ffffffff810c9545>] ? update_curr+0xf5/0x180 > > > [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 > > > [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 > > > [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 > > > [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 > > > [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c > > > [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b > > > Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f > > > RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > > RSP <ffff880221721cc8> > > > CR2: 0000000000000000 > > > ---[ end trace 13fb1e4b6e5ab21f ]--- > > > > > > Signed-off-by: Asias He <asias@redhat.com> > > > --- > > > virt/kvm/kvm_main.c | 11 ++++++----- > > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > > index 8fd325a..3c8a992 100644 > > > --- a/virt/kvm/kvm_main.c > > > +++ b/virt/kvm/kvm_main.c > > > @@ -3078,13 +3078,14 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, > > > int r; > > > int cpu; > > > > > > - r = kvm_irqfd_init(); > > > - if (r) > > > - goto out_irqfd; > > > r = kvm_arch_init(opaque); > > > if (r) > > > goto out_fail; > > > > > > + r = kvm_irqfd_init(); > > > + if (r) > > > + goto out_irqfd; > > > + > > > if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { > > > r = -ENOMEM; > > > goto out_free_0; > > > @@ -3159,10 +3160,10 @@ out_free_1: > > > out_free_0a: > > > free_cpumask_var(cpus_hardware_enabled); > > > out_free_0: > > > - kvm_arch_exit(); > > > -out_fail: > > > kvm_irqfd_exit(); > > > out_irqfd: > > > + kvm_arch_exit(); > > > +out_fail: > > > return r; > > > } > > > EXPORT_SYMBOL_GPL(kvm_init); > > > -- > > > 1.8.1.4 > > -- > Asias -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, May 07, 2013 at 06:11:33PM +0300, Michael S. Tsirkin wrote: > On Tue, May 07, 2013 at 11:05:12PM +0800, Asias He wrote: > > On Tue, May 07, 2013 at 05:59:38PM +0300, Michael S. Tsirkin wrote: > > > On Tue, May 07, 2013 at 10:54:16PM +0800, Asias He wrote: > > > > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > > > > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > > > > kvm_arch_init() will fail with -EEXIST, > > > > > > Wow. Is this intentional? > > > > I think it is. You can not be amd and intel at the same time ;-) > > > > kvm_arch_init > > > > if (kvm_x86_ops) { > > printk(KERN_ERR "kvm: already loaded the other module\n"); > > r = -EEXIST; > > goto out; > > } > > > > Interesting. So we check it with > if (kvm_x86_ops) > and later we do > kvm_x86_ops = ops; > > > This looks racy - or is something serializing > module loading? > I think module loading is serialized. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, May 07, 2013 at 06:16:09PM +0300, Gleb Natapov wrote: > On Tue, May 07, 2013 at 06:11:33PM +0300, Michael S. Tsirkin wrote: > > On Tue, May 07, 2013 at 11:05:12PM +0800, Asias He wrote: > > > On Tue, May 07, 2013 at 05:59:38PM +0300, Michael S. Tsirkin wrote: > > > > On Tue, May 07, 2013 at 10:54:16PM +0800, Asias He wrote: > > > > > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > > > > > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > > > > > kvm_arch_init() will fail with -EEXIST, > > > > > > > > Wow. Is this intentional? > > > > > > I think it is. You can not be amd and intel at the same time ;-) > > > > > > kvm_arch_init > > > > > > if (kvm_x86_ops) { > > > printk(KERN_ERR "kvm: already loaded the other module\n"); > > > r = -EEXIST; > > > goto out; > > > } > > > > > > > Interesting. So we check it with > > if (kvm_x86_ops) > > and later we do > > kvm_x86_ops = ops; > > > > > > This looks racy - or is something serializing > > module loading? > > > I think module loading is serialized. > Hmm then I don't understand ... both kvm-intel and kvm-amd *can't* be loaded at the same time: module loading fails for one of them. > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, May 07, 2013 at 06:24:48PM +0300, Michael S. Tsirkin wrote: > On Tue, May 07, 2013 at 06:16:09PM +0300, Gleb Natapov wrote: > > On Tue, May 07, 2013 at 06:11:33PM +0300, Michael S. Tsirkin wrote: > > > On Tue, May 07, 2013 at 11:05:12PM +0800, Asias He wrote: > > > > On Tue, May 07, 2013 at 05:59:38PM +0300, Michael S. Tsirkin wrote: > > > > > On Tue, May 07, 2013 at 10:54:16PM +0800, Asias He wrote: > > > > > > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > > > > > > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > > > > > > kvm_arch_init() will fail with -EEXIST, > > > > > > > > > > Wow. Is this intentional? > > > > > > > > I think it is. You can not be amd and intel at the same time ;-) > > > > > > > > kvm_arch_init > > > > > > > > if (kvm_x86_ops) { > > > > printk(KERN_ERR "kvm: already loaded the other module\n"); > > > > r = -EEXIST; > > > > goto out; > > > > } > > > > > > > > > > Interesting. So we check it with > > > if (kvm_x86_ops) > > > and later we do > > > kvm_x86_ops = ops; > > > > > > > > > This looks racy - or is something serializing > > > module loading? > > > > > I think module loading is serialized. > > > > Hmm then I don't understand ... both kvm-intel > and kvm-amd *can't* be loaded at the same time: > module loading fails for one of them. > Why would it fail? -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 7 May 2013 22:54:16 +0800 Asias He <asias@redhat.com> wrote: > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > kvm_arch_init() will fail with -EEXIST, then kvm_irqfd_exit() will be > called on the error handling path. This way, the kvm_irqfd system will > not be ready. Since we can't have the initialization as kvm module init function without forcing everyone to split modules, this is probably the best way to handle this. Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> > > This patch fix the following: > > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > PGD 0 > Oops: 0002 [#1] SMP > Modules linked in: vhost_net > CPU 6 > Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK > RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 > RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 > RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 > RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 > R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 > R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 > FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) > Stack: > ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 > 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 > ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 > Call Trace: > [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 > [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 > [<ffffffff810ac949>] queue_work+0x19/0x20 > [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 > [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 > [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 > [<ffffffff810c9545>] ? update_curr+0xf5/0x180 > [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 > [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 > [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 > [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 > [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c > [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b > Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f > RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > RSP <ffff880221721cc8> > CR2: 0000000000000000 > ---[ end trace 13fb1e4b6e5ab21f ]--- > > Signed-off-by: Asias He <asias@redhat.com> > --- > virt/kvm/kvm_main.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 8fd325a..3c8a992 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3078,13 +3078,14 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, > int r; > int cpu; > > - r = kvm_irqfd_init(); > - if (r) > - goto out_irqfd; > r = kvm_arch_init(opaque); > if (r) > goto out_fail; > > + r = kvm_irqfd_init(); > + if (r) > + goto out_irqfd; > + > if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { > r = -ENOMEM; > goto out_free_0; > @@ -3159,10 +3160,10 @@ out_free_1: > out_free_0a: > free_cpumask_var(cpus_hardware_enabled); > out_free_0: > - kvm_arch_exit(); > -out_fail: > kvm_irqfd_exit(); > out_irqfd: > + kvm_arch_exit(); > +out_fail: > return r; > } > EXPORT_SYMBOL_GPL(kvm_init); -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, May 07, 2013 at 05:54:20PM +0200, Cornelia Huck wrote: > On Tue, 7 May 2013 22:54:16 +0800 > Asias He <asias@redhat.com> wrote: > > > In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when > > kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), > > kvm_arch_init() will fail with -EEXIST, then kvm_irqfd_exit() will be > > called on the error handling path. This way, the kvm_irqfd system will > > not be ready. > > Since we can't have the initialization as kvm module init function > without forcing everyone to split modules, this is probably the best > way to handle this. > > Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Right. And please add a comment. Something like /* * kvm_arch_init makes sure there's at most one caller * for architectures that support multiple implementations, * like intel and amd on x86. * Must be called first to avoid creating conflicts * in case kvm is already setup for another implementation. */ > > > > This patch fix the following: > > > > BUG: unable to handle kernel NULL pointer dereference at (null) > > IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > PGD 0 > > Oops: 0002 [#1] SMP > > Modules linked in: vhost_net > > CPU 6 > > Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK > > RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 > > RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 > > RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 > > RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 > > R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 > > R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 > > FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) > > Stack: > > ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 > > 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 > > ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 > > Call Trace: > > [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 > > [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 > > [<ffffffff810ac949>] queue_work+0x19/0x20 > > [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 > > [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 > > [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 > > [<ffffffff810c9545>] ? update_curr+0xf5/0x180 > > [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 > > [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 > > [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 > > [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 > > [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c > > [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b > > Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f > > RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 > > RSP <ffff880221721cc8> > > CR2: 0000000000000000 > > ---[ end trace 13fb1e4b6e5ab21f ]--- > > > > Signed-off-by: Asias He <asias@redhat.com> > > --- > > virt/kvm/kvm_main.c | 11 ++++++----- > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index 8fd325a..3c8a992 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -3078,13 +3078,14 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, > > int r; > > int cpu; > > > > - r = kvm_irqfd_init(); > > - if (r) > > - goto out_irqfd; > > r = kvm_arch_init(opaque); > > if (r) > > goto out_fail; > > > > + r = kvm_irqfd_init(); > > + if (r) > > + goto out_irqfd; > > + > > if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { > > r = -ENOMEM; > > goto out_free_0; > > @@ -3159,10 +3160,10 @@ out_free_1: > > out_free_0a: > > free_cpumask_var(cpus_hardware_enabled); > > out_free_0: > > - kvm_arch_exit(); > > -out_fail: > > kvm_irqfd_exit(); > > out_irqfd: > > + kvm_arch_exit(); > > +out_fail: > > return r; > > } > > EXPORT_SYMBOL_GPL(kvm_init); -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8fd325a..3c8a992 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3078,13 +3078,14 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, int r; int cpu; - r = kvm_irqfd_init(); - if (r) - goto out_irqfd; r = kvm_arch_init(opaque); if (r) goto out_fail; + r = kvm_irqfd_init(); + if (r) + goto out_irqfd; + if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { r = -ENOMEM; goto out_free_0; @@ -3159,10 +3160,10 @@ out_free_1: out_free_0a: free_cpumask_var(cpus_hardware_enabled); out_free_0: - kvm_arch_exit(); -out_fail: kvm_irqfd_exit(); out_irqfd: + kvm_arch_exit(); +out_fail: return r; } EXPORT_SYMBOL_GPL(kvm_init);
In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), kvm_arch_init() will fail with -EEXIST, then kvm_irqfd_exit() will be called on the error handling path. This way, the kvm_irqfd system will not be ready. This patch fix the following: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 PGD 0 Oops: 0002 [#1] SMP Modules linked in: vhost_net CPU 6 Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) Stack: ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 Call Trace: [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 [<ffffffff810ac949>] queue_work+0x19/0x20 [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 [<ffffffff810c9545>] ? update_curr+0xf5/0x180 [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 RSP <ffff880221721cc8> CR2: 0000000000000000 ---[ end trace 13fb1e4b6e5ab21f ]--- Signed-off-by: Asias He <asias@redhat.com> --- virt/kvm/kvm_main.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)