| Message ID | 20191220184955.223741-21-glider@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add KernelMemorySanitizer infrastructure | expand |
On Sun, Dec 22, 2019 at 2:25 PM <glider@google.com> wrote: > > KMSAN instruments the code heavily, increasing register pressure and > preventing functions from being inlined. As a result, the kernel > requires more stack space to run. > > Rename KASAN_STACK_ORDER to EXTRA_STACK_ORDER and set EXTRA_STACK_ORDER > to 2 for KMSAN builds, effectively making the stacks 4 times larger. > > Signed-off-by: Alexander Potapenko <glider@google.com> What about CONFIG_FRAME_WARN? Do you need to change that as well to get a warning-free build? If so, what is the minimum value that you need? Arnd
On Mon, Dec 30, 2019 at 6:39 PM Arnd Bergmann <arnd@arndb.de> wrote: > > On Sun, Dec 22, 2019 at 2:25 PM <glider@google.com> wrote: > > > > KMSAN instruments the code heavily, increasing register pressure and > > preventing functions from being inlined. As a result, the kernel > > requires more stack space to run. > > > > Rename KASAN_STACK_ORDER to EXTRA_STACK_ORDER and set EXTRA_STACK_ORDER > > to 2 for KMSAN builds, effectively making the stacks 4 times larger. > > > > Signed-off-by: Alexander Potapenko <glider@google.com> > > What about CONFIG_FRAME_WARN? Do you need to change that as well to get > a warning-free build? If so, what is the minimum value that you need? Right now my config only yields a single warning about a frame of 2056 bytes. Actually, KMSAN tends to have even smaller frames than KASAN, so making the stacks so big might be too heavy-handed. I'll look into decreasing the stack sizes.
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h index 288b065955b7..ea9fbf09f43b 100644 --- a/arch/x86/include/asm/page_64_types.h +++ b/arch/x86/include/asm/page_64_types.h @@ -7,18 +7,20 @@ #endif #ifdef CONFIG_KASAN -#define KASAN_STACK_ORDER 1 +#define EXTRA_STACK_ORDER 1 +#elif defined(CONFIG_KMSAN) +#define EXTRA_STACK_ORDER 2 #else -#define KASAN_STACK_ORDER 0 +#define EXTRA_STACK_ORDER 0 #endif -#define THREAD_SIZE_ORDER (2 + KASAN_STACK_ORDER) +#define THREAD_SIZE_ORDER (2 + EXTRA_STACK_ORDER) #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER) -#define EXCEPTION_STACK_ORDER (0 + KASAN_STACK_ORDER) +#define EXCEPTION_STACK_ORDER (0 + EXTRA_STACK_ORDER) #define EXCEPTION_STKSZ (PAGE_SIZE << EXCEPTION_STACK_ORDER) -#define IRQ_STACK_ORDER (2 + KASAN_STACK_ORDER) +#define IRQ_STACK_ORDER (2 + EXTRA_STACK_ORDER) #define IRQ_STACK_SIZE (PAGE_SIZE << IRQ_STACK_ORDER) /*
KMSAN instruments the code heavily, increasing register pressure and preventing functions from being inlined. As a result, the kernel requires more stack space to run. Rename KASAN_STACK_ORDER to EXTRA_STACK_ORDER and set EXTRA_STACK_ORDER to 2 for KMSAN builds, effectively making the stacks 4 times larger. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-mm@kvack.org --- Change-Id: I1d9df161419a885bf654abff141e247366895b68 --- arch/x86/include/asm/page_64_types.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)