* Andy Lutomirski <l...@kernel.org> wrote:
> On Fri, Nov 16, 2018 at 3:27 PM Chang S. Bae <chang.seok....@intel.com> wrote:
> >
> > The helper functions that purport to write the base should just write it
> > only. It shouldn't have magic optimizations to change the index.
> >
> > Make the index explicitly changed from the caller, instead of including
> > the code in the helpers.
> >
> > Subsequently, the task write helpers do not handle for the current task
> > anymore. The range check for a base value is also factored out, to
> > minimize code redundancy from the caller.
> >
> > v2: Fix further on the task write functions. Revert the changes on the
> > task read helpers.
> >
> > v3: Fix putreg(). Edit the changelog.
> >
> > v4: Update the task write helper functions and do_arch_prctl_64(). Fix
> > the comment in putreg().
> >
> > v5: Fix preempt_disable() calls in do_arch_prctl_64()
>
> Reviewed-by: Andy Lutomirski <l...@kernel.org>
>
> Ingo, Thomas: can we get this in x86/urgent, please?
Sadly this commit introduced a boot failure on both an Intel and an AMD
64-bit testbox.
Symptoms range from silent bootup hang in early userspace to segfaults
like this:
[ 21.885741] random: systemd: uninitialized urandom read (16 bytes read)
[ 21.964778] systemd[1]: segfault at 28 ip 00005584d8d8247d sp
00007ffc7a05aed0 error 4 in systemd[5584d8d0d000+137000]
[ 21.977664] Code: c3 4c 89 ff e8 94 78 fa ff eb bb 48 89 c3 eb f1 00 00 00
00 00 00 00 00 00 00 00 00 00 41 55 41 54 55 53 48 89 fd 48 83 ec 28 <64> 48 8b
04 25 28 00 00 00 48 89 44 24 18 31 c0 48 85 ff 74 6e 48
[ 22.000004] systemd[1]: segfault at 28 ip 00005584d8db0a3d sp
00007ffc7a05a7e0 error 4 in systemd[5584d8d0d000+137000]
[ 22.012869] Code: 49 89 e9 ba 67 01 00 00 bf 04 00 00 00 31 c0 e8 c9 1c 03
00 59 31 c0 5e e9 ff fa ff ff 41 54 55 53 89 fb 48 81 ec 40 01 00 00 <64> 48 8b
04 25 28 00 00 00 48 89 84 24 38 01 00 00 31 c0 e8 fb 92
I've zapped the commit from x86/urgent because it's clearly not ready
yet.
I used a fairly regular distro .config and a fairly regular distro -
nothing fancy.
Thanks,
Ingo
