From: Olaf Kirch The way we incremented the NLM cookie in nlmclnt_next_cookie was not thread safe. This patch changes the counter to an atomic_t Signed-off-by: Olaf Kirch Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- fs/lockd/clntproc.c | 10 +++++----- include/linux/lockd/lockd.h | 1 + 2 files changed, 6 insertions(+), 5 deletions(-) diff -puN fs/lockd/clntproc.c~knfsd-make-nlmclnt_next_cookie-smp-safe fs/lockd/clntproc.c --- a/fs/lockd/clntproc.c~knfsd-make-nlmclnt_next_cookie-smp-safe +++ a/fs/lockd/clntproc.c @@ -36,14 +36,14 @@ static const struct rpc_call_ops nlmclnt /* * Cookie counter for NLM requests */ -static u32 nlm_cookie = 0x1234; +static atomic_t nlm_cookie = ATOMIC_INIT(0x1234); -static inline void nlmclnt_next_cookie(struct nlm_cookie *c) +void nlmclnt_next_cookie(struct nlm_cookie *c) { - memcpy(c->data, &nlm_cookie, 4); - memset(c->data+4, 0, 4); + u32 cookie = atomic_inc_return(&nlm_cookie); + + memcpy(c->data, &cookie, 4); c->len=4; - nlm_cookie++; } static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner) diff -puN include/linux/lockd/lockd.h~knfsd-make-nlmclnt_next_cookie-smp-safe include/linux/lockd/lockd.h --- a/include/linux/lockd/lockd.h~knfsd-make-nlmclnt_next_cookie-smp-safe +++ a/include/linux/lockd/lockd.h @@ -157,6 +157,7 @@ int nlmclnt_block(struct nlm_wait *bl u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *); void nlmclnt_recovery(struct nlm_host *); int nlmclnt_reclaim(struct nlm_host *, struct file_lock *); +void nlmclnt_next_cookie(struct nlm_cookie *); /* * Host cache _