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authorLi Lingfeng <lilingfeng3@huawei.com>2025-04-14 22:38:52 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-06-27 11:11:15 +0100
commitd622c2ee6c08147ab8c9b9e37d93b6e95d3258e0 (patch)
tree1a7889bef836a56b671d6bb9008464dcd01aef9e
parent7a75a956692aa64211a9e95781af1ec461642de4 (diff)
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: f4e44b393389 ("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>
-rw-r--r--fs/nfsd/nfssvc.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 49e2f32102ab..45f1bb2c6f13 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -406,13 +406,13 @@ static int nfsd_startup_net(struct net *net, const struct cred *cred)
if (ret)
goto out_filecache;
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+ nfsd4_ssc_init_umount_work(nn);
+#endif
ret = nfs4_state_start_net(net);
if (ret)
goto out_reply_cache;
-#ifdef CONFIG_NFSD_V4_2_INTER_SSC
- nfsd4_ssc_init_umount_work(nn);
-#endif
nn->nfsd_net_up = true;
return 0;