Re: [Qemu-devel] [PATCH for-4.1] linux-user: Make sigaltstack stacks per-thread

[Richard Henderson]

On 7/25/19 6:16 AM, Peter Maydell wrote:
> The alternate signal stack set up by the sigaltstack syscall is
> supposed to be per-thread.  We were incorrectly implementing it as
> process-wide.  This causes problems for guest binaries that rely on
> this.  Notably the Go runtime does, and so we were seeing crashes
> caused by races where two guest threads might incorrectly both
> execute on the same stack simultaneously.
> 
> Replace the global target_sigaltstack_used with a field
> sigaltstack_used in the TaskState, and make all the references to the
> old global instead get a pointer to the TaskState and use the field.
> 
> Fixes: https://bugs.launchpad.net/qemu/+bug/1696773
> Signed-off-by: Peter Maydell <address@hidden>
> ---

Reviewed-by: Richard Henderson <address@hidden>


r~