nfsd: Initialize ssc before laundromat_work to prevent NULL dereference

commit b31da62889e6d610114d81dc7a6edbcaa503fcf8 upstream.

In nfs4_state_start_net(), laundromat_work may access nfsd_ssc through
nfs4_laundromat -> nfsd4_ssc_expire_umount. If nfsd_ssc isn't initialized,
this can cause NULL pointer dereference.

Normally the delayed start of laundromat_work allows sufficient time for
nfsd_ssc initialization to complete. However, when the kernel waits too
long for userspace responses (e.g. in nfs4_state_start_net ->
nfsd4_end_grace -> nfsd4_record_grace_done -> nfsd4_cld_grace_done ->
cld_pipe_upcall -> __cld_pipe_upcall -> wait_for_completion path), the
delayed work may start before nfsd_ssc initialization finishes.

Fix this by moving nfsd_ssc initialization before starting laundromat_work.

Fixes: f4e44b3933 ("NFSD: delay unmount source's export after inter-server copy completed.")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Li Lingfeng
2025-04-14 22:38:52 +08:00
committed by Greg Kroah-Hartman
parent e7e943ddd1
commit 5060e1a5fe

View File

@@ -432,13 +432,13 @@ static int nfsd_startup_net(struct net *net, const struct cred *cred)
if (ret) if (ret)
goto out_filecache; goto out_filecache;
#ifdef CONFIG_NFSD_V4_2_INTER_SSC
nfsd4_ssc_init_umount_work(nn);
#endif
ret = nfs4_state_start_net(net); ret = nfs4_state_start_net(net);
if (ret) if (ret)
goto out_reply_cache; goto out_reply_cache;
#ifdef CONFIG_NFSD_V4_2_INTER_SSC
nfsd4_ssc_init_umount_work(nn);
#endif
nn->nfsd_net_up = true; nn->nfsd_net_up = true;
return 0; return 0;