[Devel] [PATCH rh7 25/39] kasan: remove the unnecessary WARN_ONCE from quarantine.c

Andrey Ryabinin aryabinin at virtuozzo.com
Thu Sep 14 19:51:42 MSK 2017

From: Alexander Potapenko <glider at google.com>

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.

Link: http://lkml.kernel.org/r/1470929182-101413-1-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider at google.com>
Acked-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov at google.com>
Cc: Andrey Konovalov <adech.fo at gmail.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim at lge.com>
Cc: Kuthonuzo Luruo <kuthonuzo.luruo at hpe.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>

(cherry picked from commit bcbf0d566b6e59a6e873bfe415cc415111a819e2)
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.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 b6728a33a4ac..baabaad4a4aa 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) /
 	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;

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