From: Marco Elver <elver@google.com> mainline inclusion from mainline-v5.11-rc1 commit 55a2346c7ac4 category: bugfix issue: #I3ZXZF CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------- Avoid setting up watchpoints on NULL pointers, as otherwise we would crash inside the KCSAN runtime (when checking for value changes) instead of the instrumented code. Because that may be confusing, skip any address less than PAGE_SIZE. Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Wei Li <liwei391@huawei.com> Reviewed-by: Jian Cheng <cj.chengjian@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Yu Changchun <yuchangchun1@huawei.com> --- kernel/kcsan/encoding.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/kcsan/encoding.h b/kernel/kcsan/encoding.h index 1a6db2f797ac..4f73db6d1407 100644 --- a/kernel/kcsan/encoding.h +++ b/kernel/kcsan/encoding.h @@ -48,7 +48,11 @@ 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 -- 2.22.0