@@ -1315,6 +1315,8 @@ int ksys_ipc(unsigned int call, int first, unsigned long second,
unsigned long third, void __user * ptr, long fifth);
int compat_ksys_ipc(u32 call, int first, int second,
u32 third, u32 ptr, u32 fifth);
+long ksys_futex_wake(void __user *uaddr, unsigned int nr_wake,
+ unsigned int flags);
/*
* The following kernel syscall equivalents are just wrappers to fs-internal
@@ -1328,6 +1328,8 @@ static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
put_user(0, tsk->clear_child_tid);
do_futex(tsk->clear_child_tid, FUTEX_WAKE,
1, NULL, NULL, 0, 0);
+ ksys_futex_wake(tsk->clear_child_tid, 1,
+ FUTEX_32 | FUTEX_SHARED_FLAG);
}
tsk->clear_child_tid = NULL;
}
@@ -420,18 +420,8 @@ COMPAT_SYSCALL_DEFINE4(futex_wait, void __user *, uaddr, compat_u64, val,
}
#endif
-/**
- * sys_futex_wake - Wake a number of futexes waiting on an address
- * @uaddr: Address of futex to be woken up
- * @nr_wake: Number of futexes waiting in uaddr to be woken up
- * @flags: Flags for size and shared
- *
- * Wake `nr_wake` threads waiting at uaddr.
- *
- * Returns the number of woken threads on success, error code otherwise.
- */
-SYSCALL_DEFINE3(futex_wake, void __user *, uaddr, unsigned int, nr_wake,
- unsigned int, flags)
+long ksys_futex_wake(void __user *uaddr, unsigned int nr_wake,
+ unsigned int flags)
{
unsigned int size = flags & FUTEX_SIZE_MASK, futex_flags = 0;
@@ -447,6 +437,22 @@ SYSCALL_DEFINE3(futex_wake, void __user *, uaddr, unsigned int, nr_wake,
return futex_wake(uaddr, futex_flags, nr_wake, FUTEX_BITSET_MATCH_ANY);
}
+/**
+ * sys_futex_wake - Wake a number of futexes waiting on an address
+ * @uaddr: Address of futex to be woken up
+ * @nr_wake: Number of futexes waiting in uaddr to be woken up
+ * @flags: Flags for size and shared
+ *
+ * Wake `nr_wake` threads waiting at uaddr.
+ *
+ * Returns the number of woken threads on success, error code otherwise.
+ */
+SYSCALL_DEFINE3(futex_wake, void __user *, uaddr, unsigned int, nr_wake,
+ unsigned int, flags)
+{
+ return ksys_futex_wake(uaddr, nr_wake, flags);
+}
+
#ifdef CONFIG_COMPAT
static int compat_futex_parse_requeue(struct compat_futex_requeue __user *rq,
void __user **uaddr, unsigned int *flags)
To make pthreads works as expected if they are using futex2, wake clear_child_tid with futex2 as well. This is make applications that uses waitpid() (and clone(CLONE_CHILD_SETTID)) wake while waiting for the child to terminate. Given that apps should not mix futex() and futex2(), any correct app will trigger a harmless noop wakeup on the interface that it isn't using. Signed-off-by: André Almeida <andrealmeid@collabora.com> --- This commit is here for the intend to show what we need to do in order to get a full NPTL working on top of futex2. It should be merged after we talk to glibc folks on the details around the futex_wait() side. For instance, we could use this as an opportunity to use private futexes or 8bit sized futexes, but both sides need to use the exactly same flags. --- include/linux/syscalls.h | 2 ++ kernel/fork.c | 2 ++ kernel/futex2.c | 30 ++++++++++++++++++------------ 3 files changed, 22 insertions(+), 12 deletions(-)