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authorJ. Bruce Fields <bfields@citi.umich.edu>2010-04-24 21:35:43 +0200
committerJ. Bruce Fields <bfields@citi.umich.edu>2010-05-03 14:32:31 +0200
commit26c0c75e69265961e891ed80b38fb62a548ab371 (patch)
tree1ecbc767a1b2ad3e8f25d88e918076806d8c2eb1 /fs/nfsd/nfs4state.c
parentnfsd4: fix filehandle comment (diff)
downloadlinux-26c0c75e69265961e891ed80b38fb62a548ab371.tar.xz
linux-26c0c75e69265961e891ed80b38fb62a548ab371.zip
nfsd4: fix unlikely race in session replay case
In the replay case, the renew_client(session->se_client); happens after we've droppped the sessionid_lock, and without holding a reference on the session; so there's nothing preventing the session being freed before we get here. Thanks to Benny Halevy for catching a bug in an earlier version of this patch. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Acked-by: Benny Halevy <bhalevy@panasas.com>
Diffstat (limited to 'fs/nfsd/nfs4state.c')
-rw-r--r--fs/nfsd/nfs4state.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index bba9fff49cfe..737315c61e7e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1443,11 +1443,10 @@ nfsd4_sequence(struct svc_rqst *rqstp,
cstate->slot = slot;
cstate->session = session;
- /* Hold a session reference until done processing the compound:
- * nfsd4_put_session called only if the cstate slot is set.
- */
- nfsd4_get_session(session);
out:
+ /* Hold a session reference until done processing the compound. */
+ if (cstate->session)
+ nfsd4_get_session(cstate->session);
spin_unlock(&sessionid_lock);
/* Renew the clientid on success and on replay */
if (cstate->session) {