On Fri, Jul 02, 2021 at 05:21:09PM +0800, Zhen Lei wrote: > Move the evaluation expression "size - offset" after the "if (offset < 0)" > judgment statement to eliminate a false positive produced by the UBSAN. > > No functional changes. > > ========================================================================== > UBSAN: Undefined behaviour in fs/iomap.c:1435:9 > signed integer overflow: > 0 - -9223372036854775808 cannot be represented in type 'long long int' I don't understand. I thought we defined the behaviour of signed integer overflow in the kernel with whatever-the-gcc-flag-is?
