[PATCH 09/10] riscv: fix livelock in uaccess

[Björn Töpel]

Al Viro <viro at zeniv.linux.org.uk> writes:

> riscv equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling"
> If e.g. get_user() triggers a page fault and a fatal signal is caught, we might
> end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything
> to page tables.  In such case we must *not* return to the faulting insn -
> that would repeat the entire thing without making any progress; what we need
> instead is to treat that as failed (user) memory access.
>
> Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>

Reproduced with Mark's userland program -- thanks!

Tested-by: Björn Töpel <bjorn at kernel.org>