Messages in this thread | | | Date | Mon, 4 Mar 2019 20:26:25 -0800 | From | Matthew Wilcox <> | Subject | Re: [PATCH] fs: Avoid signed overflow UBSAN warning |
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On Sat, Feb 23, 2019 at 05:02:10PM +0800, Hongbo Yao wrote: > 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.
You don't need to be this verbose to fix it.
> - offset += file->f_pos; > + offset = (u64)file->f_pos + (u64)offset;
offset += (u64)file->f_pos;
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