UBSAN: shift-out-of-bounds in fs/locks.c:2572:16
left shift of 1 by 63 places cannot be represented in type 'long long int'
Switch the calculation method to ((quarter - 1) * 2 + 1) can help us
eliminate this false positive.
On the other hand, the old implementation has problems with char and
short types, although not currently involved.
printf("%d: %x\n", sizeof(char), INT_LIMIT(char));
printf("%d: %x\n", sizeof(short), INT_LIMIT(short));
1: ffffff7f
2: ffff7fff
Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
include/linux/fs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e654435f16512c1..88d42e2daed9f6c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1131,7 +1131,7 @@ struct file_lock_context {
/* The following constant reflects the upper bound of the file/locking space */
#ifndef OFFSET_MAX
-#define INT_LIMIT(x) (~((x)1 << (sizeof(x)*8 - 1)))
+#define INT_LIMIT(x) ((((x)1 << (sizeof(x) * 8 - 2)) - 1) * 2 + 1)
#define OFFSET_MAX INT_LIMIT(loff_t)
#define OFFT_OFFSET_MAX INT_LIMIT(off_t)
#endif
--
2.25.1
