diff options
authorAnna Schumaker <>2021-06-02 14:31:20 -0400
committerTrond Myklebust <>2021-06-03 10:14:42 -0400
commit476bdb04c501fc64bf3b8464ffddefc8dbe01577 (patch)
parent0b4f132b15f988831dfca8f96af272e437eacf05 (diff)
NFS: Fix use-after-free in nfs4_init_client()
KASAN reports a use-after-free when attempting to mount two different exports through two different NICs that belong to the same server. Olga was able to hit this with kernels starting somewhere between 5.7 and 5.10, but I traced the patch that introduced the clear_bit() call to 4.13. So something must have changed in the refcounting of the clp pointer to make this call to nfs_put_client() the very last one. Fixes: 8dcbec6d20 ("NFSv41: Handle EXCHID4_FLAG_CONFIRMED_R during NFSv4.1 migration") Cc: # 4.13+ Signed-off-by: Anna Schumaker <> Signed-off-by: Trond Myklebust <>
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 889a9f4c0310..42719384e25f 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -435,8 +435,8 @@ struct nfs_client *nfs4_init_client(struct nfs_client *clp,
nfs_mark_client_ready(clp, -EPERM);
- nfs_put_client(clp);
clear_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags);
+ nfs_put_client(clp);
return old;