diff options
| author | Stefano Garzarella <sgarzare@redhat.com> | 2026-04-01 11:21:53 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-02 08:18:56 -0700 |
| commit | b18c833888742ca9de80c250f9d40d0e97caa9f6 (patch) | |
| tree | 3afad919650cab1e04a4fd7435302daabba4e481 | |
| parent | 70f73562d278d9f88e7095e327f2a50082a82c65 (diff) | |
vsock: initialize child_ns_mode_locked in vsock_net_init()
The `child_ns_mode_locked` field lives in `struct net`, which persists
across vsock module reloads. When the module is unloaded and reloaded,
`vsock_net_init()` resets `mode` and `child_ns_mode` back to their
default values, but does not reset `child_ns_mode_locked`.
The stale lock from the previous module load causes subsequent writes
to `child_ns_mode` to silently fail: `vsock_net_set_child_mode()` sees
the old lock, skips updating the actual value, and returns success
when the requested mode matches the stale lock. The sysctl handler
reports no error, but `child_ns_mode` remains unchanged.
Steps to reproduce:
$ modprobe vsock
$ echo local > /proc/sys/net/vsock/child_ns_mode
$ cat /proc/sys/net/vsock/child_ns_mode
local
$ modprobe -r vsock
$ modprobe vsock
$ echo local > /proc/sys/net/vsock/child_ns_mode
$ cat /proc/sys/net/vsock/child_ns_mode
global <--- expected "local"
Fix this by initializing `child_ns_mode_locked` to 0 (unlocked) in
`vsock_net_init()`, so the write-once mechanism works correctly after
module reload.
Fixes: 102eab95f025 ("vsock: lock down child_ns_mode as write-once")
Reported-by: Jin Liu <jinl@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>
Link: https://patch.msgid.link/20260401092153.28462-1-sgarzare@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/vmw_vsock/af_vsock.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 2f7d94d682cb..d912ed2f012a 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -2928,6 +2928,7 @@ static void vsock_net_init(struct net *net) net->vsock.mode = vsock_net_child_mode(current->nsproxy->net_ns); net->vsock.child_ns_mode = net->vsock.mode; + net->vsock.child_ns_mode_locked = 0; } static __net_init int vsock_sysctl_init_net(struct net *net) |