cf13435b73
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 <mikey@neuling.org> Reviewed-by: Breno Leitao <leitao@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.