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From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 9 Nov 2017 11:12:02 +0000
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Subject: Re: [Qemu-devel] [PATCH 1/4] linux-user/s390x: Mask si_addr for
 SIGSEGV
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To: Richard Henderson <richard.henderson@linaro.org>
Cc: QEMU Developers <qemu-devel@nongnu.org>, Riku Voipio <riku.voipio@iki.fi>, Laurent Vivier <laurent@vivier.eu>, "patches@linaro.org" <patches@linaro.org>

On 8 November 2017 at 21:18, Richard Henderson
<richard.henderson@linaro.org> wrote:
> On 11/06/2017 07:33 PM, Peter Maydell wrote:
>> For s390x, the address passed to a signal handler in the
>> siginfo_t si_addr field is masked (in the kernel this is done in
>> do_sigbus() and do_sigsegv() in arch/s390/mm/fault.c). Implement
>> this architecture-specific oddity in linux-user.
>>
>> This is one of the issues described in
>> https://bugs.launchpad.net/qemu/+bug/1705118
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>> ---
>>  linux-user/main.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> Accurate, but really seems like a s390x kernel bug.

The kernel code goes out of its way to do the masking, so if it's
a bug presumably it's a "retain back compat with some older
bug" thing...

thanks
-- PMM