Re: [BUG] OpenRISC exec init fails, bisected to 0886551 ("initramfs: finish fput() before accessing any binary from initramfs")

[Lokesh Vutla]

On Thursday 04 May 2017 12:41 PM, Stafford Horne wrote:
> Hello,
> 
> While booting the v4.11 kernel I found the below issue.
> 
> The summary of the issue mentions
> 
>     Commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
>     schedule_work() for completing fput(), but did not guarantee calling
>     __fput() after unpacking initramfs.  Because of this, there is a
>     possibility that during boot a driver can see ETXTBSY when it tries to
>     load a binary from initramfs as fput() is still pending on that binary.
> 
> It seems this patch (0886551) introduces that issue though?
> 
> I am looking into it, but any suggestions would be helpful.

Can you check if flush_delayed_fput() is being called? Do you have
CONFIG_INITRAMFS_FORCE enabled?

Can I see complete boot log?

Thanks and regards,
Lokesh

> 
> BOOT LOG
> 
>   Compiled-in FDT at c03b9100
>   Linux version 4.10.0-10351-g0886551 (shorne@xxxxxxxxxxxxxxxxxxxxx) (gcc version 5.4.0 (GCC) ) #223 Thu May 4 16:01:02 JST 2017
>   CPU: OpenRISC-0 (revision 0) @20 MHz
>   ...
>   Freeing unused kernel memory: 2856K
>   This architecture does not have kernel memory protection.
>   Failed to execute /init (error -26)
>   Starting init: /sbin/init exists but couldn't execute it (error -26)
>   Starting init: /bin/sh exists but couldn't execute it (error -26)
>   Kernel panic - not syncing: No working init found.  Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
>   ---[ end Kernel panic - not syncing: No working init found.  Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
> 
> 
> TO REPRODUCE
> 
> The failure is intermittent.
> 
> Using some tools:
>   - initramfs: https://github.com/stffrdhrn/or1k-utils
>   - compiler: https://github.com/openrisc/or1k-gcc/releases (or1k-linux-5.4.0-20170218.tar.xz)
>   - qemu: version 2.9
> 
> Make and run using:
>   make ARCH=openrisc defconfig
>   make -j5 ARCH=openrisc CROSS_COMPILE=or1k-linux- \
>   CONFIG_INITRAMFS_SOURCE="../openrisc/or1k-utils/initramfs ../openrisc/or1k-utils/initramfs.devnodes"
> 
>   qemu-system-or1k -cpu or1200 -M or1k-sim -kernel vmlinux -serial stdio \
>   -nographic -monitor none
> 
> -Stafford
>