The patch titled
Subject: mm/kasan/quarantine.c: make quarantine_lock a raw_spinlock_t
has been added to the -mm tree. Its filename is
mm-kasan-make-quarantine_lock-a-raw_spinlock_t.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-kasan-make-quarantine_lock-a-raw_spinlock_t.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-kasan-make-quarantine_lock-a-raw_spinlock_t.patch
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------------------------------------------------------
From: Clark Williams <williams@xxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxx: slightly altered the commit message]
Link: http://lkml.kernel.org/r/20181010214945.5owshc3mlrh74z4b@xxxxxxxxxxxxx
Signed-off-by: Clark Williams <williams@xxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/kasan/quarantine.c~mm-kasan-make-quarantine_lock-a-raw_spinlock_t
+++ a/mm/kasan/quarantine.c
@@ -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_me
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_me
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
*/
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);
_
Patches currently in -mm which might be from williams@xxxxxxxxxx are
mm-kasan-make-quarantine_lock-a-raw_spinlock_t.patch
