From 2ec55f8024db859d70f14c26e91ca044328dd50d Mon Sep 17 00:00:00 2001 From: Manfred Spraul Date: Wed, 12 Jul 2017 14:35:13 -0700 Subject: [PATCH] ipc/sem.c: avoid ipc_rcu_putref for failed ipc_addid() Loosely based on a patch from Kees Cook : - id and retval can be merged - if ipc_addid() fails, then use call_rcu() directly. The difference is that call_rcu is used for failed ipc_addid() calls, to continue to guaranteed an rcu delay for security_sem_free(). Link: http://lkml.kernel.org/r/20170525185107.12869-14-manfred@colorfullife.com Signed-off-by: Manfred Spraul Cc: Kees Cook Cc: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/sem.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/ipc/sem.c b/ipc/sem.c index 445a5b5eb88f..2b2ed56e0fde 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -479,7 +479,6 @@ static struct sem_array *sem_alloc(size_t nsems) */ static int newary(struct ipc_namespace *ns, struct ipc_params *params) { - int id; int retval; struct sem_array *sma; key_t key = params->key; @@ -520,10 +519,10 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) sma->sem_nsems = nsems; sma->sem_ctime = get_seconds(); - id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); - if (id < 0) { - ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); - return id; + retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); + if (retval < 0) { + call_rcu(&sma->sem_perm.rcu, sem_rcu_free); + return retval; } ns->used_sems += nsems;