linux

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Andrey Konovalov 3f41b60938 kasan: fix random seed generation for tag-based mode

There are two issues with assigning random percpu seeds right now:

1. We use for_each_possible_cpu() to iterate over cpus, but cpumask is
   not set up yet at the moment of kasan_init(), and thus we only set
   the seed for cpu #0.

2. A call to get_random_u32() always returns the same number and produces
   a message in dmesg, since the random subsystem is not yet initialized.

Fix 1 by calling kasan_init_tags() after cpumask is set up.

Fix 2 by using get_cycles() instead of get_random_u32(). This gives us
lower quality random numbers, but it's good enough, as KASAN is meant to
be used as a debugging tool and not a mitigation.

Link: http://lkml.kernel.org/r/1f815cc914b61f3516ed4cc9bfd9eeca9bd5d9de.1550677973.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2019-02-21 09:01:00 -08:00

cache.S

arm64: Fix minor issues with the dcache_by_line_op macro

2018-12-10 15:03:51 +00:00

context.c

arm64: mm: Drop the unused cpu parameter

2018-10-09 17:17:23 +01:00

copypage.c

arm64: Defer dcache flush in __cpu_copy_user_page

2015-12-17 11:07:13 +00:00

dma-mapping.c

arm64/xen: fix xen-swiotlb cache flushing