strace 4.15 released

[Dmitry V. Levin]

On Mon, Feb 13, 2017 at 04:47:05PM +0000, James Cowgill wrote:
> Hi,
> 
> 
> On 13/02/17 14:40, Dmitry V. Levin wrote:
> > On Mon, Jan 09, 2017 at 08:54:52PM +0300, Dmitry V. Levin wrote:
> >> On Mon, Jan 09, 2017 at 05:31:37PM +0000, James Cowgill wrote:
> >>> On 06/01/17 00:51, Dmitry V. Levin wrote:
> >>>> On Tue, Jan 03, 2017 at 06:02:44PM +0000, James Cowgill wrote:
> >>>>> On 20/12/16 00:36, Steve McIntyre wrote:
> >>>>>> On Tue, Dec 20, 2016 at 03:16:17AM +0300, Dmitry V. Levin wrote:
> >>>>>>> On Tue, Dec 20, 2016 at 12:50:29AM +0100, Nahim El Atmani wrote:
> >>>>>>>> On Mon, 19 Dec 2016 18:30:29 +0000, Steve McIntyre wrote:
> >>>>>>>>> I'm seeing test suite failures on mips[1], mipsel[2] and mips64el[3]
> >>>>>>>>> on Debian machines.
> >>>>>>>>>
> >>>>>>>>> The 32-bit builds are both showing issues with fault injection. I
> >>>>>>>>> can't follow what the code is meant to be doing here, so no
> >>>>>>>>> ideas on what's wrong. :-(
> >>>>>>>>
> >>>>>>>> As Dmitry said earlier:
> >>>>>>>>
> >>>>>>>> On Tue, 15 Nov 2016 15:43:59 +0300, Dmitry V. Levin wrote:
> >>>>>>>>> Well, the mips kernel does not implement substitution of syscall numbers
> >>>>>>>>
> >>>>>>>> So it looks like the test has failed to SKIP on this target.
> >>>>>>>
> >>>>>>> As I'm not 100% sure there is no kernel support for mips, I decided
> >>>>>>> not to skip the test on mips until somebody investigates.
> >>>>>>
> >>>>>> Ah, OK. James Cowgill is my friendly local mips expert - let's see
> 
> >>>>>> what he thinks... :-)
> >>>>>
> >>>>> I've had a look and I think there is a kernel bug here - specifically
> >>>>> affecting 32-bit programs run on 64-bit kernels (like all the Debian
> >>>>> buildds and the porterbox are). An extra PTRACE_SYSCALL stop is
> >>>>> happening which confuses everything. I'll look some more tomorrow.
> >>>>
> >>>> Indeed, it seems to be a kernel bug in scall64-o32.S and scall64-n32.S.
> >>>>
> >>>> According to current arch/mips/kernel/scall64-o32.S:trace_a_syscall
> >>>> (the same applies to arch/mips/kernel/scall64-n32.S),
> >>>>
> >>>> if the syscall number after the first syscall_trace_enter call is out
> >>>> of range, there is a jump to not_o32_scall which in turn jumps to
> >>>> arch/mips/kernel/scall64-64.S:handle_sys64 (or to handle_sysn32 which
> >>>> then jumps on to handle_sys64).
> >>>>
> >>>> Handle_sys64, unsurprisingly, does all over again, starting with
> >>>> a syscall_trace_enter call, which appears to be the second one
> >>>> and causes that extra syscall stop you observe with 32-bit tracees
> >>>> running on 64-bit kernels.
> >>>
> >>> Just going through all the MIPS testsuite bugs again:
> >>>
> >>> fault_injection*
> >>> The kernel bug above (no patch yet).
> >>
> >> I couldn't find an easy fix for this kernel bug.  Any ideas?
> > 
> > OK, there is not going to be any fix for this kernel bug in v4.10,
> > so I'd rather disable scno tampering tests when MIPS ABI is o32
> > but the kernel is n64.
> > 
> > Is there any simple way for MIPS o32 userspace to find out whether
> > the kernel is not a native MIPS o32?  Something less hackish
> > than manually invoking a MIPS n64 syscall?
> 
> uname -m is a bit less hackish:
> 
> 32-bit kernel: $(uname -m) = mips
> 64-bit kernel: $(uname -m) = mips64

No, it didn't work out, 64-bit kernel pretends it's mips:
http://www.einval.com/debian/strace/build-logs/mipsel/2017-02-14-040242-log-eller-TESTFAIL.txt


-- 
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