[PATCH] kasan: remove the unnecessary WARN_ONCE from quarantine.c

[PATCH] kasan: remove the unnecessary WARN_ONCE from quarantine.c

[Alexander Potapenko]

It's quite unlikely that the user will so little memory that the
per-CPU quarantines won't fit into the given fraction of the available
memory. Even in that case he won't be able to do anything with the
information given in the warning.

Signed-off-by: Alexander Potapenko <glider@google.com>
---
 mm/kasan/quarantine.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index b6728a3..baabaad 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -217,11 +217,8 @@ void quarantine_reduce(void)
 	new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
 		QUARANTINE_FRACTION;
 	percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
-	if (WARN_ONCE(new_quarantine_size < percpu_quarantines,
-		"Too little memory, disabling global KASAN quarantine.\n"))
-		new_quarantine_size = 0;
-	else
-		new_quarantine_size -= percpu_quarantines;
+	new_quarantine_size = (new_quarantine_size < percpu_quarantines) ?
+		0 : new_quarantine_size - percpu_quarantines;
 	WRITE_ONCE(quarantine_size, new_quarantine_size);
 
 	last = global_quarantine.head;
-- 
2.8.0.rc3.226.g39d4020

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Re: [PATCH] kasan: remove the unnecessary WARN_ONCE from quarantine.c

[Andrey Ryabinin]

On 08/11/2016 06:26 PM, Alexander Potapenko wrote:
> It's quite unlikely that the user will so little memory that the
> per-CPU quarantines won't fit into the given fraction of the available
> memory. Even in that case he won't be able to do anything with the
> information given in the warning.
> 
> Signed-off-by: Alexander Potapenko <glider@google.com>

Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>

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