Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (b0db954c) · Commits · 戴 / test

kernel/futex.c

+22 −19

Original line number	Diff line number	Diff line
		@@ -716,7 +716,7 @@ static int futex_lock_pi_atomic(u32 __user uaddr, struct futex_hash_bucket hb,
		struct futex_pi_state **ps,
		struct task_struct *task, int set_waiters)
		{
		int lock_taken, ret, ownerdied = 0;
		int lock_taken, ret, force_take = 0;
		u32 uval, newval, curval, vpid = task_pid_vnr(task);

		retry:
		@@ -755,17 +755,15 @@ retry:
		newval = curval \| FUTEX_WAITERS;

		/*
		* There are two cases, where a futex might have no owner (the
		* owner TID is 0): OWNER_DIED. We take over the futex in this
		* case. We also do an unconditional take over, when the owner
		* of the futex died.
		*
		* This is safe as we are protected by the hash bucket lock !
		* Should we force take the futex? See below.
		*/
		if (unlikely(force_take)) {
		/*
		* Keep the OWNER_DIED and the WAITERS bit and set the
		* new TID value.
		*/
		if (unlikely(ownerdied \|\| !(curval & FUTEX_TID_MASK))) {
		/* Keep the OWNER_DIED bit */
		newval = (curval & ~FUTEX_TID_MASK) \| vpid;
		ownerdied = 0;
		force_take = 0;
		lock_taken = 1;
		}

		@@ -775,7 +773,7 @@ retry:
		goto retry;

		/*
		* We took the lock due to owner died take over.
		* We took the lock due to forced take over.
		*/
		if (unlikely(lock_taken))
		return 1;
		@@ -790,20 +788,25 @@ retry:
		switch (ret) {
		case -ESRCH:
		/*
		* No owner found for this futex. Check if the
		* OWNER_DIED bit is set to figure out whether
		* this is a robust futex or not.
		* We failed to find an owner for this
		* futex. So we have no pi_state to block
		* on. This can happen in two cases:
		*
		* 1) The owner died
		* 2) A stale FUTEX_WAITERS bit
		*
		* Re-read the futex value.
		*/
		if (get_futex_value_locked(&curval, uaddr))
		return -EFAULT;

		/*
		* We simply start over in case of a robust
		* futex. The code above will take the futex
		* and return happy.
		* If the owner died or we have a stale
		* WAITERS bit the owner TID in the user space
		* futex is 0.
		*/
		if (curval & FUTEX_OWNER_DIED) {
		ownerdied = 1;
		if (!(curval & FUTEX_TID_MASK)) {
		force_take = 1;
		goto retry;
		}
		default:

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