Re: [PATCH] compiler: enable CONFIG_OPTIMIZE_INLINING forcibly

[Charles Keepax]

On Fri, Sep 27, 2019 at 12:43:33PM +0200, Nicolas Saenz Julienne wrote:
> On Fri, 2019-08-30 at 12:43 +0900, Masahiro Yamada wrote:
> > Commit 9012d011660e ("compiler: allow all arches to enable
> > CONFIG_OPTIMIZE_INLINING") allowed all architectures to enable
> > this option. A couple of build errors were reported by randconfig,
> > but all of them have been ironed out.
> > 
> > Towards the goal of removing CONFIG_OPTIMIZE_INLINING entirely
> > (and it will simplify the 'inline' macro in compiler_types.h),
> > this commit changes it to always-on option. Going forward, the
> > compiler will always be allowed to not inline functions marked
> > 'inline'.
> > 
> > This is not a problem for x86 since it has been long used by
> > arch/x86/configs/{x86_64,i386}_defconfig.
> > 
> > I am keeping the config option just in case any problem crops up for
> > other architectures.
> > 
> > The code clean-up will be done after confirming this is solid.
> > 
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> 
> [ Adding some ARM people as they might be able to help ]
> 
> This was found to cause a regression on a Raspberry Pi 2 B built with
> bcm2835_defconfig which among other things has no SMP support.
> 
> The relevant logs (edited to remove the noise) are:
> 
> [    5.827333] Run /init as init process
> Loading, please wait...
> Failed to set SO_PASSCRED: Bad address
> Failed to bind netlink socket: Bad address
> Failed to create manager: Bad address
> Failed to set SO_PASSCRED: Bad address
> [    9.021623] systemd[1]: SO_PASSCRED failed: Bad address
> [!!!!!!] Failed to start up manager.
> [    9.079148] systemd[1]: Freezing execution.
> 
> I looked into it, it turns out that the call to get_user() in sock_setsockopt()
> is returning -EFAULT. Down the assembly rabbit hole that get_user() is I
> found-out that it's the macro 'check_uaccess' who's triggering the error.
> 
> I'm clueless at this point, so I hope you can give me some hints on what's
> going bad here.
> 

Not sure I can add much in terms of a solution, but I can at
least confirm I am seeing exactly the same issue, on my Zynq
based ARM system.

Thanks,
Charles