On Fri, 2023-12-08 at 14:32 +0100, Alexander Potapenko wrote: > On Tue, Nov 21, 2023 at 11:07 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> > wrote: > > > > The constraints of the DFLTCC inline assembly are not precise: they > > do not communicate the size of the output buffers to the compiler, > > so > > it cannot automatically instrument it. > > KMSAN usually does a poor job instrumenting inline assembly. > Wouldn't be it better to switch to pure C ZLIB implementation, making > ZLIB_DFLTCC depend on !KMSAN? Normally I would agree, but the kernel DFLTCC code base is synced with the zlib-ng code base to the extent that it uses the zlib-ng code style instead of the kernel code style, and MSAN annotations are already a part of the zlib-ng code base. So I would prefer to keep them for consistency. The code is also somewhat tricky in the are of buffer management, so I find it beneficial to have it checked for uninitialized memory accesses.
