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mm/kasan/quarantine.c: make quarantine_lock a raw_spinlock_t 

The static lock quarantine_lock is used in quarantine.c to protect the
quarantine queue datastructures.  It is taken inside quarantine queue
manipulation routines (quarantine_put(), quarantine_reduce() and
quarantine_remove_cache()), with IRQs disabled.  This is not a problem on
a stock kernel but is problematic on an RT kernel where spin locks are
sleeping spinlocks, which can sleep and can not be acquired with disabled
interrupts.

Convert the quarantine_lock to a raw spinlock_t.  The usage of
quarantine_lock is confined to quarantine.c and the work performed while
the lock is held is used for debug purpose.

[bigeasy@linutronix.de: slightly altered the commit message]
Link: http://lkml.kernel.org/r/20181010214945.5owshc3mlrh74z4b@linutronix.de
Signed-off-by: Clark Williams <williams@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Clark Williams 2018-10-26 15:10:32 -07:00 committed by Linus Torvalds
parent df06b37ffe
commit 026d1eaf5e
1 changed files with 9 additions and 9 deletions
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18
mm/kasan/quarantine.c
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@ -103,7 +103,7 @@ static int quarantine_head;
static int quarantine_tail;
/* Total size of all objects in global_quarantine across all batches. */
static unsigned long quarantine_size;
static DEFINE_SPINLOCK(quarantine_lock);
static DEFINE_RAW_SPINLOCK(quarantine_lock);
DEFINE_STATIC_SRCU(remove_cache_srcu);
/* Maximum size of the global queue. */
@ -190,7 +190,7 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
if (unlikely(q->bytes > QUARANTINE_PERCPU_SIZE)) {
qlist_move_all(q, &temp);
spin_lock(&quarantine_lock);
raw_spin_lock(&quarantine_lock);
WRITE_ONCE(quarantine_size, quarantine_size + temp.bytes);
qlist_move_all(&temp, &global_quarantine[quarantine_tail]);
if (global_quarantine[quarantine_tail].bytes >=
@ -203,7 +203,7 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
if (new_tail != quarantine_head)
quarantine_tail = new_tail;
}
spin_unlock(&quarantine_lock);
raw_spin_unlock(&quarantine_lock);
}
local_irq_restore(flags);
@ -230,7 +230,7 @@ void quarantine_reduce(void)
* expected case).
*/
srcu_idx = srcu_read_lock(&remove_cache_srcu);
spin_lock_irqsave(&quarantine_lock, flags);
raw_spin_lock_irqsave(&quarantine_lock, flags);
/*
* Update quarantine size in case of hotplug. Allocate a fraction of
@ -254,7 +254,7 @@ void quarantine_reduce(void)
quarantine_head = 0;
}
spin_unlock_irqrestore(&quarantine_lock, flags);
raw_spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, NULL);
srcu_read_unlock(&remove_cache_srcu, srcu_idx);
@ -310,17 +310,17 @@ void quarantine_remove_cache(struct kmem_cache *cache)
*/
on_each_cpu(per_cpu_remove_cache, cache, 1);
spin_lock_irqsave(&quarantine_lock, flags);
raw_spin_lock_irqsave(&quarantine_lock, flags);
for (i = 0; i < QUARANTINE_BATCHES; i++) {
if (qlist_empty(&global_quarantine[i]))
continue;
qlist_move_cache(&global_quarantine[i], &to_free, cache);
/* Scanning whole quarantine can take a while. */
spin_unlock_irqrestore(&quarantine_lock, flags);
raw_spin_unlock_irqrestore(&quarantine_lock, flags);
cond_resched();
spin_lock_irqsave(&quarantine_lock, flags);
raw_spin_lock_irqsave(&quarantine_lock, flags);
}
spin_unlock_irqrestore(&quarantine_lock, flags);
raw_spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, cache);