Re: [next]: LTP: getxattr05.c:97: TFAIL: unshare(CLONE_NEWUSER) failed: ENOSPC (28)

[Anders Roxell]

On Wed, 12 Jan 2022 at 14:18, Christian Brauner
<christian.brauner@xxxxxxxxxx> wrote:
>
> On Wed, Jan 12, 2022 at 05:15:37PM +0530, Naresh Kamboju wrote:
> > While testing LTP syscalls with Linux next 20220110 (and till date 20220112)
> > on x86_64, i386, arm and arm64 the following tests failed.
> >
> > tst_test.c:1365: TINFO: Timeout per run is 0h 15m 00s
> > getxattr05.c:87: TPASS: Got same data when acquiring the value of
> > system.posix_acl_access twice
> > getxattr05.c:97: TFAIL: unshare(CLONE_NEWUSER) failed: ENOSPC (28)
> > tst_test.c:391: TBROK: Invalid child (13545) exit value 1
> >
> > fanotify17.c:176: TINFO: Test #1: Global groups limit in privileged user ns
> > fanotify17.c:155: TFAIL: unshare(CLONE_NEWUSER) failed: ENOSPC (28)
> > tst_test.c:391: TBROK: Invalid child (14739) exit value 1
> >
> > sendto03.c:48: TBROK: unshare(268435456) failed: ENOSPC (28)
> >
> > setsockopt05.c:45: TBROK: unshare(268435456) failed: ENOSPC (28)
> >
> > strace output:
> > --------------
> > [pid   481] wait4(-1, 0x7fff52f5ae8c, 0, NULL) = -1 ECHILD (No child processes)
> > [pid   481] clone(child_stack=NULL,
> > flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
> > child_tidptr=0x7f3af0fa7a10) = 483
> > strace: Process 483 attached
> > [pid   481] wait4(-1,  <unfinished ...>
> > [pid   483] unshare(CLONE_NEWUSER)      = -1 ENOSPC (No space left on device)
>
> This looks like another regression in the ucount code. Reverting the
> following commit fixes it and makes the getxattr05 test work again:
>
> commit 0315b634f933b0f12cfa82660322f6186c1aa0f4
> Author: Alexey Gladkov <legion@xxxxxxxxxx>
> Date:   Fri Dec 17 15:48:23 2021 +0100
>
>     ucounts: Split rlimit and ucount values and max values
>
>     Since the semantics of maximum rlimit values are different, it would be
>     better not to mix ucount and rlimit values. This will prevent the error
>     of using inc_count/dec_ucount for rlimit parameters.
>
>     This patch also renames the functions to emphasize the lack of
>     connection between rlimit and ucount.
>
>     v2:
>     - Fix the array-index-out-of-bounds that was found by the lkp project.
>
>     Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
>     Signed-off-by: Alexey Gladkov <legion@xxxxxxxxxx>
>     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@xxxxxxxxxx
>     Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
>
> The issue only surfaces if /proc/sys/user/max_user_namespaces is
> actually written to.

I did a git bisect and that pointed me to this patch too.

Cheers,
Anders