Re: [PATCH] accel/tcg: Fix translation exception on invalid instruction

[Richard Henderson]

On 4/13/21 6:23 AM, Ilya Leoshkevich wrote:
> * When tb_gen_code() is called on that page, tb->size ends up being 0

This is the bug, in target/s390x.  Perhaps we need to add an assert that size 
!= 0 after translation...


> Fix by special-casing tb->size == 0: since there is no useful code, we
> don't need to link pages in this case.

Yes we do, because we need to link to the page to notice when changes to that 
page occur.

While this won't happen in the specific case of uretprobe, it affects every 
other instance of a TB which begins with an illegal instruction.


r~