From: Hongbo Yao <yaohongbo@huawei.com>
To: <viro@zeniv.linux.org.uk>, <linux-fsdevel@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linuxarm@huawei.com>
Subject: [PATCH] fs: Avoid signed overflow UBSAN warning
Date: Sat, 23 Feb 2019 17:02:10 +0800 [thread overview]
Message-ID: <20190223090210.116847-1-yaohongbo@huawei.com> (raw)
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
next reply other threads:[~2019-02-23 8:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-23 9:02 Hongbo Yao [this message]
2019-03-05 4:26 ` [PATCH] fs: Avoid signed overflow UBSAN warning Matthew Wilcox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190223090210.116847-1-yaohongbo@huawei.com \
--to=yaohongbo@huawei.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxarm@huawei.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).