On Wed, Oct 14, 2020 at 03:51:00PM -0700, Linus Torvalds wrote: > On Wed, Oct 14, 2020 at 3:27 PM Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > > > This patch is causing crashes in WireGuard's CI over at > > https://www.wireguard.com/build-status/ . Apparently sending a simple > > network packet winds up triggering refcount_t's warn-on-saturate code. I > > Ouch. > > The C parts look fairly straightforward, and I don't see how they > could cause that odd refcount issue. > > So I assume it's the low-level asm code conversion that is buggy. And > it's apparently the 32-bit conversion, since your ppc64 status looks > fine. > > I think it's this instruction: > > addi r1,r1,16 > > that should be removed from the function exit, because Al removed the > > - stwu r1,-16(r1) > > on function entry. > > So I think you end up with a corrupt stack pointer and basically > random behavior. Gyahh... ACK, and I really wonder how the hell has it managed to avoid crashing on testing. Mea culpa, folks.
