Hi Andy, On Tue, 24 Feb 2026 at 17:21, Andy Shevchenko <[email protected]> wrote: > > On Tue, Feb 24, 2026 at 05:04:27PM +0000, Fuad Tabba wrote: > > sized_strscpy() performs word-at-a-time writes to the destination > > buffer. If the destination buffer is not aligned to unsigned long, > > direct assignment causes UBSAN misaligned-access errors. > > > > Use put_unaligned() to safely write the words to the destination. > > Have you measured the performance impact?
Not directly. I verified the disassembly for both x86_64 and aarch64. On x86_64, both the raw pointer cast and put_unaligned() compile down to mov %rdi,(%rsi). On aarch64, both compile to str x0, [x1]. > Have you read the comment near to > > if (IS_ENABLED(CONFIG_KMSAN)) Not until now to be honest. However, are you asking whether put_unaligned() breaks KMSAN? I don't think it does, max is set to 0 when KMSAN is enabled, this entire while loop is bypassed. Thanks, /fuad > ? > > -- > With Best Regards, > Andy Shevchenko > >
