Re: [PATCH v5 0/4] linux-user: Fix siginfo_t contents when jumping to non-readable pages

[Richard Henderson]

On 8/18/22 09:55, Vivian Wang wrote:
> On 8/17/22 23:05, Ilya Leoshkevich wrote:
> > Hi,
> >
> > I noticed that when we get a SEGV due to jumping to non-readable
> > memory, sometimes si_addr and program counter in siginfo_t are slightly
> > off. I tracked this down to the assumption that translators stop before
> > the end of a page, while in reality they may stop right after it.
>
> Hi,
>
> Could this be related to issue 1155 [1]? On RISC-V, I'm getting incorrect 
> [m|s]tval/[m|s]epc combinations for page faults in system emulation and incorrect si_addr 
> and program counter on SIGSEGV in user emulation. Since it seems to only affect 
> instructions that cross page boundaries, and RISC-V also has variable length instructions, 
> it seems that I've run into the same problem as what is fixed here.

It seems likely, and the code at the end of riscv_tr_translate_insn is wrong.

> Could this fix be extended be extended to targets/riscv?

I'll write up something.


r~