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Subject[PATCH v2 2/2] fs: clear a UBSAN shift-out-of-bounds warning
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 type_max() 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

Suggested-by: Eric Biggers <>
Signed-off-by: Zhen Lei <>
include/linux/fs.h | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index e654435f16512c1..a384741b1449457 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1131,9 +1131,8 @@ 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 OFFSET_MAX INT_LIMIT(loff_t)
+#define OFFSET_MAX type_max(loff_t)
+#define OFFT_OFFSET_MAX type_max(off_t)

extern void send_sigio(struct fown_struct *fown, int fd, int band);
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