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Subject[PATCH] fs: Avoid signed overflow UBSAN warning
Date
I ran into this:
UBSAN: Undefined behaviour in fs/read_write.c:251:11
signed integer overflow:
9223372036854775805 + 9223372036854775805 cannot be represented in
type 'long long int'

Use unsigned types to do math, it doesn't throw a UBSAN warning
when it does overflow.This patch doesn't change generated code.

Signed-off-by: Hongbo Yao <yaohongbo@huawei.com>
---
fs/read_write.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index 8f08d4a2aa9a..0509e81afc8e 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -248,7 +248,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int whence)
retval = file->f_pos;
goto out;
}
- offset += file->f_pos;
+ offset = (u64)file->f_pos + (u64)offset;
break;
case SEEK_DATA:
/*
--
2.20.1
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