From: Elena Reshetova <elena.reshetova@xxxxxxxxx> Subject: ipc: convert sem_undo_list.refcnt from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Link: http://lkml.kernel.org/r/1499417992-3238-3-git-send-email-elena.reshetova@xxxxxxxxx Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx> Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: David Windsor <dwindsor@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Serge Hallyn <serge@xxxxxxxxxx> Cc: <arozansk@xxxxxxxxxx> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/sem.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff -puN ipc/sem.c~ipc-convert-sem_undo_listrefcnt-from-atomic_t-to-refcount_t ipc/sem.c --- a/ipc/sem.c~ipc-convert-sem_undo_listrefcnt-from-atomic_t-to-refcount_t +++ a/ipc/sem.c @@ -122,7 +122,7 @@ struct sem_undo { * that may be shared among all a CLONE_SYSVSEM task group. */ struct sem_undo_list { - atomic_t refcnt; + refcount_t refcnt; spinlock_t lock; struct list_head list_proc; }; @@ -1642,7 +1642,7 @@ static inline int get_undo_list(struct s if (undo_list == NULL) return -ENOMEM; spin_lock_init(&undo_list->lock); - atomic_set(&undo_list->refcnt, 1); + refcount_set(&undo_list->refcnt, 1); INIT_LIST_HEAD(&undo_list->list_proc); current->sysvsem.undo_list = undo_list; @@ -2041,7 +2041,7 @@ int copy_semundo(unsigned long clone_fla error = get_undo_list(&undo_list); if (error) return error; - atomic_inc(&undo_list->refcnt); + refcount_inc(&undo_list->refcnt); tsk->sysvsem.undo_list = undo_list; } else tsk->sysvsem.undo_list = NULL; @@ -2070,7 +2070,7 @@ void exit_sem(struct task_struct *tsk) return; tsk->sysvsem.undo_list = NULL; - if (!atomic_dec_and_test(&ulp->refcnt)) + if (!refcount_dec_and_test(&ulp->refcnt)) return; for (;;) { _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
