On Mon, 2018-09-24 at 07:27:04 UTC, Michael Neuling wrote: > When we treclaim we store the userspace checkpointed r13 to a scratch > SPR and then later save the scratch SPR to the user thread struct. > > Unfortunately, this doesn't work as accessing the user thread struct > can take an SLB fault and the SLB fault handler will write the same > scratch SPRG that now contains the userspace r13. > > To fix this, we store r13 to the kernel stack (which can't fault) > before we access the user thread struct. > > Found by running P8 guest + powervm + disable_1tb_segments + TM. Seen > as a random userspace segfault with r13 looking like a kernel address. > > Signed-off-by: Michael Neuling <mi...@neuling.org> > Reviewed-by: Breno Leitao <lei...@debian.org>
Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/cf13435b730a502e814c63c84d93db cheers
