From: Andrey Konovalov <andreyknvl@xxxxxxxxx> Subject: kasan: test: avoid corrupting memory in kasan_rcu_uaf kasan_rcu_uaf() writes to freed memory via kasan_rcu_reclaim(), which is only safe with the GENERIC mode (as it uses quarantine). For other modes, this test corrupts kernel memory, which might result in a crash. Turn the write into a read. Link: https://lkml.kernel.org/r/b6f2c3bf712d2457c783fa59498225b66a634f62.1628779805.git.andreyknvl@xxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_kasan_module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/test_kasan_module.c~kasan-test-avoid-corrupting-memory-in-kasan_rcu_uaf +++ a/lib/test_kasan_module.c @@ -71,7 +71,7 @@ static noinline void __init kasan_rcu_re struct kasan_rcu_info, rcu); kfree(fp); - fp->i = 1; + ((volatile struct kasan_rcu_info *)fp)->i; } static noinline void __init kasan_rcu_uaf(void) _
