Subject: Re: bug#35662: Really relocatable binaries crash with Permission denied

From: Ludovic Courtès <[email-masked]>
Date: Mon, 13 May 2019 22:39:21 +0200

"pelzflorian (Florian Pelz)" <[email-masked]> skribis:

> On Mon, May 13, 2019 at 03:54:11PM +0200, Ludovic Courtès wrote:
>> Can you show the mount options of you root file system?
>> 
>>   mount | grep 'on / '
>> 
>
> [f_pelz12@tux6 ~]$ mount | grep 'on / '
> rpool/data/subvol-161199-disk-0 on / type zfs (rw,noatime,xattr,posixacl)

I suspect ZFS-on-Linux (right?) is doing something unusual here:
mount(2) specifies the following reasons for EACCESS, and I don’t see
anything that would apply:

--8<---------------cut here---------------start------------->8---
EACCES A component of a path was not searchable.  (See also path_resolution(7).)

EACCES Mounting a read-only filesystem was attempted without giving the
       MS_RDONLY flag.

       The file system may be read-only for various reasons, including:
       it resides on a read-only optical disk; it is resides on a device
       with a physical switch that has been set to mark the device read-
       only; the filesystem implementation was compiled with read-only
       support; or errors were detected when initially mounting the
       filesystem, so that it was marked read-only and can't be
       remounted as read-write (until the errors are fixed).

       Some filesystems instead return the error EROFS on an attempt to
       mount a read-only filesystem.

EACCES The block device source is located on a filesystem mounted with
       the MS_NODEV option.
--8<---------------cut here---------------end--------------->8---

What do the following commands do on this system?

--8<---------------cut here---------------start------------->8---
$ mkdir -p /tmp/test/lib
$ unshare -mrf mount /lib /tmp/test/lib -o bind,readonly
--8<---------------cut here---------------end--------------->8---

Thanks,
Ludo’.