Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'locking_urgent_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Borislav Petkov:
"Fix ordering in the queued writer lock's slowpath"
* tag 'locking_urgent_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/qrwlock: Fix ordering in queued_write_lock_slowpath()
+4
-3
+4
-3
kernel/locking/qrwlock.c
+4
-3
kernel/locking/qrwlock.c
···
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*/
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void queued_write_lock_slowpath(struct qrwlock *lock)
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{
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+
int cnts;
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+
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/* Put the writer into the wait queue */
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arch_spin_lock(&lock->wait_lock);
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67
···
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/* When no more readers or writers, set the locked flag */
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do {
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-
atomic_cond_read_acquire(&lock->cnts, VAL == _QW_WAITING);
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-
} while (atomic_cmpxchg_relaxed(&lock->cnts, _QW_WAITING,
80
-
_QW_LOCKED) != _QW_WAITING);
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+
cnts = atomic_cond_read_relaxed(&lock->cnts, VAL == _QW_WAITING);
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+
} while (!atomic_try_cmpxchg_acquire(&lock->cnts, &cnts, _QW_LOCKED));
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unlock:
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arch_spin_unlock(&lock->wait_lock);
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}