| Message ID | 20221108101705.45981-1-yuancan@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] vhost/vsock: Fix error handling in vhost_vsock_init() | expand |
On Tue, Nov 08, 2022 at 10:17:05AM +0000, Yuan Can wrote: >A problem about modprobe vhost_vsock failed is triggered with the >following log given: > >modprobe: ERROR: could not insert 'vhost_vsock': Device or resource busy > >The reason is that vhost_vsock_init() returns misc_register() directly >without checking its return value, if misc_register() failed, it returns >without calling vsock_core_unregister() on vhost_transport, resulting the >vhost_vsock can never be installed later. >A simple call graph is shown as below: > > vhost_vsock_init() > vsock_core_register() # register vhost_transport > misc_register() > device_create_with_groups() > device_create_groups_vargs() > dev = kzalloc(...) # OOM happened > # return without unregister vhost_transport > >Fix by calling vsock_core_unregister() when misc_register() returns error. > >Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") >Signed-off-by: Yuan Can <yuancan@huawei.com> >--- >Changes in v2: >- change to the correct Fixes: tag I forgot to mention that anyway the patch was okay for me :-) and so: Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Thanks, Stefano > > drivers/vhost/vsock.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > >diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c >index 5703775af129..10a7d23731fe 100644 >--- a/drivers/vhost/vsock.c >+++ b/drivers/vhost/vsock.c >@@ -959,7 +959,14 @@ static int __init vhost_vsock_init(void) > VSOCK_TRANSPORT_F_H2G); > if (ret < 0) > return ret; >- return misc_register(&vhost_vsock_misc); >+ >+ ret = misc_register(&vhost_vsock_misc); >+ if (ret) { >+ vsock_core_unregister(&vhost_transport.transport); >+ return ret; >+ } >+ >+ return 0; > }; > > static void __exit vhost_vsock_exit(void) >-- >2.17.1 >
On Tue, Nov 8, 2022 at 6:19 PM Yuan Can <yuancan@huawei.com> wrote: > > A problem about modprobe vhost_vsock failed is triggered with the > following log given: > > modprobe: ERROR: could not insert 'vhost_vsock': Device or resource busy > > The reason is that vhost_vsock_init() returns misc_register() directly > without checking its return value, if misc_register() failed, it returns > without calling vsock_core_unregister() on vhost_transport, resulting the > vhost_vsock can never be installed later. > A simple call graph is shown as below: > > vhost_vsock_init() > vsock_core_register() # register vhost_transport > misc_register() > device_create_with_groups() > device_create_groups_vargs() > dev = kzalloc(...) # OOM happened > # return without unregister vhost_transport > > Fix by calling vsock_core_unregister() when misc_register() returns error. > > Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") > Signed-off-by: Yuan Can <yuancan@huawei.com> Acked-by: Jason Wang <jasowang@redhat.com> > --- > Changes in v2: > - change to the correct Fixes: tag > > drivers/vhost/vsock.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index 5703775af129..10a7d23731fe 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -959,7 +959,14 @@ static int __init vhost_vsock_init(void) > VSOCK_TRANSPORT_F_H2G); > if (ret < 0) > return ret; > - return misc_register(&vhost_vsock_misc); > + > + ret = misc_register(&vhost_vsock_misc); > + if (ret) { > + vsock_core_unregister(&vhost_transport.transport); > + return ret; > + } > + > + return 0; > }; > > static void __exit vhost_vsock_exit(void) > -- > 2.17.1 >
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 5703775af129..10a7d23731fe 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -959,7 +959,14 @@ static int __init vhost_vsock_init(void) VSOCK_TRANSPORT_F_H2G); if (ret < 0) return ret; - return misc_register(&vhost_vsock_misc); + + ret = misc_register(&vhost_vsock_misc); + if (ret) { + vsock_core_unregister(&vhost_transport.transport); + return ret; + } + + return 0; }; static void __exit vhost_vsock_exit(void)
A problem about modprobe vhost_vsock failed is triggered with the following log given: modprobe: ERROR: could not insert 'vhost_vsock': Device or resource busy The reason is that vhost_vsock_init() returns misc_register() directly without checking its return value, if misc_register() failed, it returns without calling vsock_core_unregister() on vhost_transport, resulting the vhost_vsock can never be installed later. A simple call graph is shown as below: vhost_vsock_init() vsock_core_register() # register vhost_transport misc_register() device_create_with_groups() device_create_groups_vargs() dev = kzalloc(...) # OOM happened # return without unregister vhost_transport Fix by calling vsock_core_unregister() when misc_register() returns error. Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") Signed-off-by: Yuan Can <yuancan@huawei.com> --- Changes in v2: - change to the correct Fixes: tag drivers/vhost/vsock.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)