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| author | Paul E. McKenney <paulmck@kernel.org> | 2020-11-19 19:38:25 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-11-19 19:38:25 -0800 |
| commit | c4638ff0644bb114b27c65fbc975a1597030beb0 (patch) | |
| tree | cc37d928c1365bf3600b54f466cea1627445e2d4 /kernel | |
| parent | 7fc91fc8450655e7ba941d61663afcaf65cefb78 (diff) | |
| parent | 1d094cefc37e5ed4dec44a41841c8628f6b548a2 (diff) | |
| download | linux-c4638ff0644bb114b27c65fbc975a1597030beb0.tar.bz2 | |
Merge branch 'kcsan.2020.11.06a' into HEAD
kcsan.2020.11.06a: Kernel concurrency sanitizer (KCSAN) updates.
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kcsan/encoding.h | 20 | ||||
| -rw-r--r-- | kernel/kcsan/selftest.c | 3 |
2 files changed, 14 insertions, 9 deletions
diff --git a/kernel/kcsan/encoding.h b/kernel/kcsan/encoding.h index 1a6db2f797ac..7ee405524904 100644 --- a/kernel/kcsan/encoding.h +++ b/kernel/kcsan/encoding.h @@ -37,18 +37,20 @@ */ #define WATCHPOINT_ADDR_BITS (BITS_PER_LONG-1 - WATCHPOINT_SIZE_BITS) -/* - * Masks to set/retrieve the encoded data. - */ -#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) +/* 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, 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 diff --git a/kernel/kcsan/selftest.c b/kernel/kcsan/selftest.c index d98bc208d06d..9014a3a82cf9 100644 --- a/kernel/kcsan/selftest.c +++ b/kernel/kcsan/selftest.c @@ -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; |