| Message ID | 20220222094742.16359-1-sgarzare@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] vhost/vsock: don't check owner in vhost_vsock_stop() while releasing | expand |
On Tue, Feb 22, 2022 at 5:47 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > > vhost_vsock_stop() calls vhost_dev_check_owner() to check the device > ownership. It expects current->mm to be valid. > > vhost_vsock_stop() is also called by vhost_vsock_dev_release() when > the user has not done close(), so when we are in do_exit(). In this > case current->mm is invalid and we're releasing the device, so we > should clean it anyway. > > Let's check the owner only when vhost_vsock_stop() is called > by an ioctl. > > When invoked from release we can not fail so we don't check return > code of vhost_vsock_stop(). We need to stop vsock even if it's not > the owner. > > Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") > Cc: stable@vger.kernel.org > Reported-by: syzbot+1e3ea63db39f2b4440e0@syzkaller.appspotmail.com > Reported-and-tested-by: syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> > --- > v2: > - initialized `ret` in vhost_vsock_stop [Dan] > - added comment about vhost_vsock_stop() calling in the code and an explanation > in the commit message [MST] > > v1: https://lore.kernel.org/virtualization/20220221114916.107045-1-sgarzare@redhat.com > --- > drivers/vhost/vsock.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index d6ca1c7ad513..37f0b4274113 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -629,16 +629,18 @@ static int vhost_vsock_start(struct vhost_vsock *vsock) > return ret; > } > > -static int vhost_vsock_stop(struct vhost_vsock *vsock) > +static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner) > { > size_t i; > - int ret; > + int ret = 0; > > mutex_lock(&vsock->dev.mutex); > > - ret = vhost_dev_check_owner(&vsock->dev); > - if (ret) > - goto err; > + if (check_owner) { > + ret = vhost_dev_check_owner(&vsock->dev); > + if (ret) > + goto err; > + } > > for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { > struct vhost_virtqueue *vq = &vsock->vqs[i]; > @@ -753,7 +755,12 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file) > * inefficient. Room for improvement here. */ > vsock_for_each_connected_socket(vhost_vsock_reset_orphans); > > - vhost_vsock_stop(vsock); > + /* Don't check the owner, because we are in the release path, so we > + * need to stop the vsock device in any case. > + * vhost_vsock_stop() can not fail in this case, so we don't need to > + * check the return code. > + */ > + vhost_vsock_stop(vsock, false); > vhost_vsock_flush(vsock); > vhost_dev_stop(&vsock->dev); > > @@ -868,7 +875,7 @@ static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl, > if (start) > return vhost_vsock_start(vsock); > else > - return vhost_vsock_stop(vsock); > + return vhost_vsock_stop(vsock, true); > case VHOST_GET_FEATURES: > features = VHOST_VSOCK_FEATURES; > if (copy_to_user(argp, &features, sizeof(features))) > -- > 2.35.1 >
Hello: This patch was applied to netdev/net.git (master) by David S. Miller <davem@davemloft.net>: On Tue, 22 Feb 2022 10:47:42 +0100 you wrote: > vhost_vsock_stop() calls vhost_dev_check_owner() to check the device > ownership. It expects current->mm to be valid. > > vhost_vsock_stop() is also called by vhost_vsock_dev_release() when > the user has not done close(), so when we are in do_exit(). In this > case current->mm is invalid and we're releasing the device, so we > should clean it anyway. > > [...] Here is the summary with links: - [v2] vhost/vsock: don't check owner in vhost_vsock_stop() while releasing https://git.kernel.org/netdev/net/c/a58da53ffd70 You are awesome, thank you!
On Tue, Feb 22, 2022 at 10:47:42AM +0100, Stefano Garzarella wrote: > vhost_vsock_stop() calls vhost_dev_check_owner() to check the device > ownership. It expects current->mm to be valid. > > vhost_vsock_stop() is also called by vhost_vsock_dev_release() when > the user has not done close(), so when we are in do_exit(). In this > case current->mm is invalid and we're releasing the device, so we > should clean it anyway. > > Let's check the owner only when vhost_vsock_stop() is called > by an ioctl. > > When invoked from release we can not fail so we don't check return > code of vhost_vsock_stop(). We need to stop vsock even if it's not > the owner. > > Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") > Cc: stable@vger.kernel.org > Reported-by: syzbot+1e3ea63db39f2b4440e0@syzkaller.appspotmail.com > Reported-and-tested-by: syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> > --- > v2: > - initialized `ret` in vhost_vsock_stop [Dan] > - added comment about vhost_vsock_stop() calling in the code and an explanation > in the commit message [MST] > > v1: https://lore.kernel.org/virtualization/20220221114916.107045-1-sgarzare@redhat.com > --- > drivers/vhost/vsock.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index d6ca1c7ad513..37f0b4274113 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -629,16 +629,18 @@ static int vhost_vsock_start(struct vhost_vsock *vsock) return ret; } -static int vhost_vsock_stop(struct vhost_vsock *vsock) +static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner) { size_t i; - int ret; + int ret = 0; mutex_lock(&vsock->dev.mutex); - ret = vhost_dev_check_owner(&vsock->dev); - if (ret) - goto err; + if (check_owner) { + ret = vhost_dev_check_owner(&vsock->dev); + if (ret) + goto err; + } for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { struct vhost_virtqueue *vq = &vsock->vqs[i]; @@ -753,7 +755,12 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file) * inefficient. Room for improvement here. */ vsock_for_each_connected_socket(vhost_vsock_reset_orphans); - vhost_vsock_stop(vsock); + /* Don't check the owner, because we are in the release path, so we + * need to stop the vsock device in any case. + * vhost_vsock_stop() can not fail in this case, so we don't need to + * check the return code. + */ + vhost_vsock_stop(vsock, false); vhost_vsock_flush(vsock); vhost_dev_stop(&vsock->dev); @@ -868,7 +875,7 @@ static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl, if (start) return vhost_vsock_start(vsock); else - return vhost_vsock_stop(vsock); + return vhost_vsock_stop(vsock, true); case VHOST_GET_FEATURES: features = VHOST_VSOCK_FEATURES; if (copy_to_user(argp, &features, sizeof(features)))
vhost_vsock_stop() calls vhost_dev_check_owner() to check the device ownership. It expects current->mm to be valid. vhost_vsock_stop() is also called by vhost_vsock_dev_release() when the user has not done close(), so when we are in do_exit(). In this case current->mm is invalid and we're releasing the device, so we should clean it anyway. Let's check the owner only when vhost_vsock_stop() is called by an ioctl. When invoked from release we can not fail so we don't check return code of vhost_vsock_stop(). We need to stop vsock even if it's not the owner. Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") Cc: stable@vger.kernel.org Reported-by: syzbot+1e3ea63db39f2b4440e0@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> --- v2: - initialized `ret` in vhost_vsock_stop [Dan] - added comment about vhost_vsock_stop() calling in the code and an explanation in the commit message [MST] v1: https://lore.kernel.org/virtualization/20220221114916.107045-1-sgarzare@redhat.com --- drivers/vhost/vsock.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)