6.15-stable review patch. If anyone has any objections, please let me know.
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From: Li Lingfeng lilingfeng3@huawei.com
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 --- fs/nfsd/nfssvc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -396,13 +396,13 @@ static int nfsd_startup_net(struct net * 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;