Re: [PATCH] gitlab-ci: Use -fno-sanitize=function in the clang-user job

[Richard Henderson <richard.henderson@linaro.org>]

On 7/24/24 20:52, Daniel P. Berrangé wrote:
> On Wed, Jul 24, 2024 at 09:25:42AM +1000, Richard Henderson wrote:
>> With -fsanitize=undefined, which implies -fsanitize=function,
>> clang will add a "type signature" before functions.
>> It accesses funcptr-8 and funcptr-4 to do so.
>>
>> The generated TCG prologue is directly on a page boundary,
>> so these accesses segfault.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>
>> Does anyone know why we're using --extra-cflags for the clang-user
>> and clang-system jobs, as opposed to --enable-sanitizers?  It
>> certainly seems like regular users who use the normal configure
>> flag are going to run into this as well.
>>
>> Anyway, this is why the clang-user job is failing at the momemnt.
>> I can only assume that changes to our docker file, or upstream
>> distro updates have pulled in a new compiler version, because this
>> wasn't failing in this way last week.
> 
> Logs show the clang version didn't change, but it is possible the
> libubsan.so package changed, but we can't see package versions.

But the code generation definitely did -- the segv is right at the indirect function call 
to the (generated) tcg prologue.  The library is not involved at all.


> I've sent a series that will make it easier to compare pacakge
> versions between new & historical jobs in future situations like
> this:
> 
>    https://lists.nongnu.org/archive/html/qemu-devel/2024-07/msg05749.html

Nice.


r~