Re: [PATCH] Using kzalloc to avoid allocating kvm_regs from kernel stack

Zhang, Xiantao
2008-02-25T09:43:40Z

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Please use the new one. Add the check for failed allocation.

From: Xiantao Zhang <xiantao.zhang@intel.com>
Date: Mon, 25 Feb 2008 17:25:07 +0800
Subject: [PATCH] kvm: Using kzalloc to avoid allocating kvm_regs from
kernel stack.

Since the size of kvm_regs maybe too big to allocate from kernel stack,
here use kzalloc to allocate it.
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
---
virt/kvm/kvm_main.c | 21 ++++++++++++++-------
1 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cf6df51..8d4326f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -806,25 +806,32 @@ static long kvm_vcpu_ioctl(struct file *filp,
r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
break;
case KVM_GET_REGS: {
- struct kvm_regs kvm_regs;
+ struct kvm_regs *kvm_regs;

- memset(&kvm_regs, 0, sizeof kvm_regs);
- r = kvm_arch_vcpu_ioctl_get_regs(vcpu, &kvm_regs);
+ r = -ENOMEM;
+ kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
+ if (!kvm_regs)
+ goto out;
+ r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
if (r)
goto out;
r = -EFAULT;
- if (copy_to_user(argp, &kvm_regs, sizeof kvm_regs))
+ if (copy_to_user(argp, kvm_regs, sizeof(struct
kvm_regs)))
goto out;
r = 0;
break;
}
case KVM_SET_REGS: {
- struct kvm_regs kvm_regs;
+ struct kvm_regs *kvm_regs;

+ r = -ENOMEM;
+ kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
+ if (!kvm_regs)
+ goto out;
r = -EFAULT;
- if (copy_from_user(&kvm_regs, argp, sizeof kvm_regs))
+ if (copy_from_user(kvm_regs, argp, sizeof(struct
kvm_regs)))
goto out;
- r = kvm_arch_vcpu_ioctl_set_regs(vcpu, &kvm_regs);
+ r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
if (r)
goto out;
r = 0;
--
1.5.2

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From ea8d2422c93c1a386b732a34505bb040bda52b6e Mon Sep 17 00:00:00 2001
From: Xiantao Zhang <xiantao.zhang@intel.com>
Date: Mon, 25 Feb 2008 17:25:07 +0800
Subject: [PATCH] kvm: Using kzalloc to avoid allocating kvm_regs from kernel stack.

Since the size of kvm_regs maybe too big to allocate from kernel stack,
here use kzalloc to allocate it.
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
---
virt/kvm/kvm_main.c | 21 ++++++++++++++-------
1 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cf6df51..8d4326f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -806,25 +806,32 @@ static long kvm_vcpu_ioctl(struct file *filp,
r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
break;
case KVM_GET_REGS: {
- struct kvm_regs kvm_regs;
+ struct kvm_regs *kvm_regs;

- memset(&kvm_regs, 0, sizeof kvm_regs);
- r = kvm_arch_vcpu_ioctl_get_regs(vcpu, &kvm_regs);
+ r = -ENOMEM;
+ kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
+ if (!kvm_regs)
+ goto out;
+ r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
if (r)
goto out;
r = -EFAULT;
- if (copy_to_user(argp, &kvm_regs, sizeof kvm_regs))
+ if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
goto out;
r = 0;
break;
}
case KVM_SET_REGS: {
- struct kvm_regs kvm_regs;
+ struct kvm_regs *kvm_regs;

+ r = -ENOMEM;
+ kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
+ if (!kvm_regs)
+ goto out;
r = -EFAULT;
- if (copy_from_user(&kvm_regs, argp, sizeof kvm_regs))
+ if (copy_from_user(kvm_regs, argp, sizeof(struct kvm_regs)))
goto out;
- r = kvm_arch_vcpu_ioctl_set_regs(vcpu, &kvm_regs);
+ r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
if (r)
goto out;
r = 0;
--
1.5.2

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