Commit c4638ff0 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

Merge branch 'kcsan.2020.11.06a' into HEAD 

kcsan.2020.11.06a:  Kernel concurrency sanitizer (KCSAN) updates.
parents 7fc91fc8 1d094cef

kernel/kcsan/encoding.h

+11 −9
Original line number Diff line number Diff line
@@ -37,18 +37,20 @@ 
 */

#define WATCHPOINT_ADDR_BITS (BITS_PER_LONG-1 - WATCHPOINT_SIZE_BITS)



/*

 * Masks to set/retrieve the encoded data.

 */

/* Bitmasks for the encoded watchpoint access information. */

#define WATCHPOINT_WRITE_MASK	BIT(BITS_PER_LONG-1)

#define WATCHPOINT_SIZE_MASK                                                   \

	GENMASK(BITS_PER_LONG-2, BITS_PER_LONG-2 - WATCHPOINT_SIZE_BITS)

#define WATCHPOINT_ADDR_MASK                                                   \

	GENMASK(BITS_PER_LONG-3 - WATCHPOINT_SIZE_BITS, 0)

#define WATCHPOINT_SIZE_MASK	GENMASK(BITS_PER_LONG-2, WATCHPOINT_ADDR_BITS)

#define WATCHPOINT_ADDR_MASK	GENMASK(WATCHPOINT_ADDR_BITS-1, 0)

static_assert(WATCHPOINT_ADDR_MASK == (1UL << WATCHPOINT_ADDR_BITS) - 1);

static_assert((WATCHPOINT_WRITE_MASK ^ WATCHPOINT_SIZE_MASK ^ WATCHPOINT_ADDR_MASK) == ~0UL);



static inline bool check_encodable(unsigned long addr, size_t size)

{

	return size <= MAX_ENCODABLE_SIZE;

	/*

	 * While we can encode addrs<PAGE_SIZE, avoid crashing with a NULL

	 * pointer deref inside KCSAN.

	 */

	return addr >= PAGE_SIZE && size <= MAX_ENCODABLE_SIZE;

}



static inline long

kernel/kcsan/selftest.c

+3 −0
Original line number Diff line number Diff line
@@ -33,6 +33,9 @@ static bool test_encode_decode(void) 
		unsigned long addr;



		prandom_bytes(&addr, sizeof(addr));

		if (addr < PAGE_SIZE)

			addr = PAGE_SIZE;



		if (WARN_ON(!check_encodable(addr, size)))

			return false;