The patch titled
Subject: ipc/shm: do not use ipc_rcu_free()
has been added to the -mm tree. Its filename is
ipc-shm-do-not-use-ipc_rcu_free.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipc-shm-do-not-use-ipc_rcu_free.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipc-shm-do-not-use-ipc_rcu_free.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/shm.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN ipc/shm.c~ipc-shm-do-not-use-ipc_rcu_free ipc/shm.c
--- a/ipc/shm.c~ipc-shm-do-not-use-ipc_rcu_free
+++ a/ipc/shm.c
@@ -172,6 +172,11 @@ static inline void shm_lock_by_ptr(struc
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
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 *
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;
}
_
Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are
ipc-drop-non-rcu-allocation.patch
ipc-sem-do-not-use-ipc_rcu_free.patch
ipc-shm-do-not-use-ipc_rcu_free.patch
ipc-msg-do-not-use-ipc_rcu_free.patch
ipc-util-drop-ipc_rcu_free.patch
ipc-sem-avoid-ipc_rcu_alloc.patch
ipc-shm-avoid-ipc_rcu_alloc.patch
ipc-msg-avoid-ipc_rcu_alloc.patch
ipc-util-drop-ipc_rcu_alloc.patch
ipc-move-atomic_set-to-where-it-is-needed.patch
ipc-shm-remove-special-shm_alloc-free.patch
ipc-msg-remove-special-msg_alloc-free.patch
ipc-sem-drop-__sem_free.patch
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