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ipc/shm: do not use ipc_rcu_free() 

Avoid using ipc_rcu_free, since it just re-finds the original structure
pointer.  For the pre-list-init failure path, there is no RCU needed,
since it was just allocated.  It can be directly freed.

Link: http://lkml.kernel.org/r/20170525185107.12869-7-manfred@colorfullife.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zero-colors
Kees Cook 2017-07-12 14:34:53 -07:00 committed by Linus Torvalds
parent 1b4654ef72
commit 66470b1817
1 changed files with 7 additions and 2 deletions
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9
ipc/shm.c
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@ -172,6 +172,11 @@ static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
ipc_lock_object(&ipcp->shm_perm);
}
static void __shm_free(struct shmid_kernel *shp)
{
kvfree(shp);
}
static void shm_rcu_free(struct rcu_head *head)
{
struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
@ -179,7 +184,7 @@ static void shm_rcu_free(struct rcu_head *head)
struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
shm_perm);
security_shm_free(shp);
ipc_rcu_free(head);
__shm_free(shp);
}
static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
@ -557,7 +562,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
shp->shm_perm.security = NULL;
error = security_shm_alloc(shp);
if (error) {
ipc_rcu_putref(&shp->shm_perm, ipc_rcu_free);
__shm_free(shp);
return error;
}