On Wed, May 01, 2019 at 03:08:31PM -0400, Stefan Hajnoczi wrote:
On Tue, Apr 30, 2019 at 05:30:01PM -0700, Jorge E. Moreira wrote:
Avoid a race in which static variables in net/vmw_vsock/af_vsock.c are accessed (while handling interrupts) before they are initialized.
[ 4.201410] BUG: unable to handle kernel paging request at ffffffffffffffe8 [ 4.207829] IP: vsock_addr_equals_addr+0x3/0x20 [ 4.211379] PGD 28210067 P4D 28210067 PUD 28212067 PMD 0 [ 4.211379] Oops: 0000 [#1] PREEMPT SMP PTI [ 4.211379] Modules linked in: [ 4.211379] CPU: 1 PID: 30 Comm: kworker/1:1 Not tainted 4.14.106-419297-gd7e28cc1f241 #1 [ 4.211379] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 4.211379] Workqueue: virtio_vsock virtio_transport_rx_work [ 4.211379] task: ffffa3273d175280 task.stack: ffffaea1800e8000 [ 4.211379] RIP: 0010:vsock_addr_equals_addr+0x3/0x20 [ 4.211379] RSP: 0000:ffffaea1800ebd28 EFLAGS: 00010286 [ 4.211379] RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffffb94e42f0 [ 4.211379] RDX: 0000000000000400 RSI: ffffffffffffffe0 RDI: ffffaea1800ebdd0 [ 4.211379] RBP: ffffaea1800ebd58 R08: 0000000000000001 R09: 0000000000000001 [ 4.211379] R10: 0000000000000000 R11: ffffffffb89d5d60 R12: ffffaea1800ebdd0 [ 4.211379] R13: 00000000828cbfbf R14: 0000000000000000 R15: ffffaea1800ebdc0 [ 4.211379] FS: 0000000000000000(0000) GS:ffffa3273fd00000(0000) knlGS:0000000000000000 [ 4.211379] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4.211379] CR2: ffffffffffffffe8 CR3: 000000002820e001 CR4: 00000000001606e0 [ 4.211379] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 4.211379] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 4.211379] Call Trace: [ 4.211379] ? vsock_find_connected_socket+0x6c/0xe0 [ 4.211379] virtio_transport_recv_pkt+0x15f/0x740 [ 4.211379] ? detach_buf+0x1b5/0x210 [ 4.211379] virtio_transport_rx_work+0xb7/0x140 [ 4.211379] process_one_work+0x1ef/0x480 [ 4.211379] worker_thread+0x312/0x460 [ 4.211379] kthread+0x132/0x140 [ 4.211379] ? process_one_work+0x480/0x480 [ 4.211379] ? kthread_destroy_worker+0xd0/0xd0 [ 4.211379] ret_from_fork+0x35/0x40 [ 4.211379] Code: c7 47 08 00 00 00 00 66 c7 07 28 00 c7 47 08 ff ff ff ff c7 47 04 ff ff ff ff c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 8b 47 08 <3b> 46 08 75 0a 8b 47 04 3b 46 04 0f 94 c0 c3 31 c0 c3 90 66 2e [ 4.211379] RIP: vsock_addr_equals_addr+0x3/0x20 RSP: ffffaea1800ebd28 [ 4.211379] CR2: ffffffffffffffe8 [ 4.211379] ---[ end trace f31cc4a2e6df3689 ]--- [ 4.211379] Kernel panic - not syncing: Fatal exception in interrupt [ 4.211379] Kernel Offset: 0x37000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 4.211379] Rebooting in 5 seconds..
Fixes: 22b5c0b63f32 ("vsock/virtio: fix kernel panic after device hot-unplug") Cc: Stefan Hajnoczi stefanha@redhat.com Cc: "David S. Miller" davem@davemloft.net Cc: kvm@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Cc: kernel-team@android.com Cc: stable@vger.kernel.org [4.9+] Signed-off-by: Jorge E. Moreira jemoreira@google.com
net/vmw_vsock/virtio_transport.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index 15eb5d3d4750..96ab344f17bb 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -702,28 +702,27 @@ static int __init virtio_vsock_init(void) if (!virtio_vsock_workqueue) return -ENOMEM;
- ret = register_virtio_driver(&virtio_vsock_driver);
- ret = vsock_core_init(&virtio_transport.transport);
Have you checked that all transport callbacks are safe even if another CPU calls them while virtio_vsock_probe() is executing on another CPU?
I have the same doubt.
What do you think to take the 'the_virtio_vsock_mutex' in the virtio_vsock_init(), keeping the previous order?
This should prevent this issue because the virtio_vsock_probe() remains blocked in the mutex until the end of vsock_core_init().
Cheers, Stefano