3.13.11.10 -stable review patch. If anyone has any objections, please let me know.
------------------ From: David Matlack <[email protected]> commit 2ea75be3219571d0ec009ce20d9971e54af96e09 upstream. vcpu ioctls can hang the calling thread if issued while a vcpu is running. However, invalid ioctls can happen when userspace tries to probe the kind of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case, we know the ioctl is going to be rejected as invalid anyway and we can fail before trying to take the vcpu mutex. This patch does not change functionality, it just makes invalid ioctls fail faster. Signed-off-by: David Matlack <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- virt/kvm/kvm_main.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 44652f2..8d2a98a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -52,6 +52,7 @@ #include <asm/processor.h> #include <asm/io.h> +#include <asm/ioctl.h> #include <asm/uaccess.h> #include <asm/pgtable.h> @@ -1994,6 +1995,9 @@ static long kvm_vcpu_ioctl(struct file *filp, if (vcpu->kvm->mm != current->mm) return -EIO; + if (unlikely(_IOC_TYPE(ioctl) != KVMIO)) + return -EINVAL; + #if defined(CONFIG_S390) || defined(CONFIG_PPC) || defined(CONFIG_MIPS) /* * Special cases: vcpu ioctls that are asynchronous to vcpu execution, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
