From: Stefano Garzarella Date: Wed, 1 Apr 2026 09:21:53 +0000 (+0200) Subject: vsock: initialize child_ns_mode_locked in vsock_net_init() X-Git-Tag: v7.0-rc7~28^2~3 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b18c833888742ca9de80c250f9d40d0e97caa9f6;p=thirdparty%2Fkernel%2Flinux.git 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 Signed-off-by: Stefano Garzarella Reviewed-by: Bobby Eshleman Link: https://patch.msgid.link/20260401092153.28462-1-sgarzare@redhat.com Signed-off-by: Jakub Kicinski --- 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)