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authorNeilBrown <neil@brown.name>2025-07-18 11:26:14 +1000
committerChuck Lever <chuck.lever@oracle.com>2025-08-05 10:31:33 -0400
commite5a73150776f18547ee685c9f6bfafe549714899 (patch)
tree30b3f5023fa45d27c9ffeb2d2c1bb5e78f22d4c9
parentnfsd: don't set the ctime on delegated atime updates (diff)
downloadlinux-e5a73150776f18547ee685c9f6bfafe549714899.tar.gz
linux-e5a73150776f18547ee685c9f6bfafe549714899.zip
nfsd: avoid ref leak in nfsd_open_local_fh()
If two calls to nfsd_open_local_fh() race and both successfully call nfsd_file_acquire_local(), they will both get an extra reference to the net to accompany the file reference stored in *pnf. One of them will fail to store (using xchg()) the file reference in *pnf and will drop that reference but WON'T drop the accompanying reference to the net. This leak means that when the nfs server is shut down it will hang in nfsd_shutdown_net() waiting for &nn->nfsd_net_free_done. This patch adds the missing nfsd_net_put(). Reported-by: Mike Snitzer <snitzer@kernel.org> Fixes: e6f7e1487ab5 ("nfs_localio: simplify interface to nfsd for getting nfsd_file") Cc: stable@vger.kernel.org Signed-off-by: NeilBrown <neil@brown.name> Tested-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
-rw-r--r--fs/nfsd/localio.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
index 4f6468eb2adf..cb237f1b902a 100644
--- a/fs/nfsd/localio.c
+++ b/fs/nfsd/localio.c
@@ -103,10 +103,11 @@ nfsd_open_local_fh(struct net *net, struct auth_domain *dom,
if (nfsd_file_get(new) == NULL)
goto again;
/*
- * Drop the ref we were going to install and the
- * one we were going to return.
+ * Drop the ref we were going to install (both file and
+ * net) and the one we were going to return (only file).
*/
nfsd_file_put(localio);
+ nfsd_net_put(net);
nfsd_file_put(localio);
localio = new;
}