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

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

[Christian Brauner]

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@kernel.org>
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@intel.com>
    Signed-off-by: Alexey Gladkov <legion@kernel.org>
    Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
    Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

The issue only surfaces if /proc/sys/user/max_user_namespaces is
actually written to.

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@ubuntu.com> 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@kernel.org>
> 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@intel.com>
>     Signed-off-by: Alexey Gladkov <legion@kernel.org>
>     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
>     Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>
> 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

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

[Christian Brauner]

On Wed, Jan 12, 2022 at 02:22:42PM +0100, Anders Roxell wrote:
> On Wed, 12 Jan 2022 at 14:18, Christian Brauner
> <christian.brauner@ubuntu.com> 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@kernel.org>
> > 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@intel.com>
> >     Signed-off-by: Alexey Gladkov <legion@kernel.org>
> >     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
> >     Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> >
> > 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.

Uhm, doesn't this want to be:

diff --git a/kernel/ucount.c b/kernel/ucount.c
index 22070f004e97..108c6a879cd8 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -264,7 +264,7 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
        long ret = 0;

        for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-               long new = atomic_long_add_return(v, &iter->ucount[type]);
+               long new = atomic_long_add_return(v, &iter->rlimit[type]);
                if (new < 0 || new > max)
                        ret = LONG_MAX;
                else if (iter == ucounts)
@@ -279,7 +279,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
        struct ucounts *iter;
        long new = -1; /* Silence compiler warning */
        for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-               long dec = atomic_long_sub_return(v, &iter->ucount[type]);
+               long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
                WARN_ON_ONCE(dec < 0);
                if (iter == ucounts)
                        new = dec;


otherwise,

inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_NPROC, 1)

means

long inc_rlimit_ucounts(struct ucounts *ucounts, UCOUNT_RLIMIT_NPROC, long v)
{
	struct ucounts *iter;
	long max = LONG_MAX;
	long ret = 0;

	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
		long new = atomic_long_add_return(v, &iter->ucount[UCOUNT_RLIMIT_NPROC]);
		if (new < 0 || new > max)
			ret = LONG_MAX;
		else if (iter == ucounts)
			ret = new;
		max = get_userns_rlimit_max(iter->ns, UCOUNT_RLIMIT_NPROC);
	}
	return ret;
}

which means that UCOUNT_RLIMIT_NPROC overwrites ucount[UCOUNT_RLIMIT_NPROC]?

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

[Alexey Gladkov]

On Wed, Jan 12, 2022 at 03:02:54PM +0100, Christian Brauner wrote:
> On Wed, Jan 12, 2022 at 02:22:42PM +0100, Anders Roxell wrote:
> > On Wed, 12 Jan 2022 at 14:18, Christian Brauner
> > <christian.brauner@ubuntu.com> 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@kernel.org>
> > > 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@intel.com>
> > >     Signed-off-by: Alexey Gladkov <legion@kernel.org>
> > >     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
> > >     Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> > >
> > > 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.
> 
> Uhm, doesn't this want to be:

Yes. I miss it. I tried not to mix the logic, but I myself stepped on this
problem.

> 
> diff --git a/kernel/ucount.c b/kernel/ucount.c
> index 22070f004e97..108c6a879cd8 100644
> --- a/kernel/ucount.c
> +++ b/kernel/ucount.c
> @@ -264,7 +264,7 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
>         long ret = 0;
> 
>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
> -               long new = atomic_long_add_return(v, &iter->ucount[type]);
> +               long new = atomic_long_add_return(v, &iter->rlimit[type]);
>                 if (new < 0 || new > max)
>                         ret = LONG_MAX;
>                 else if (iter == ucounts)
> @@ -279,7 +279,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
>         struct ucounts *iter;
>         long new = -1; /* Silence compiler warning */
>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
> -               long dec = atomic_long_sub_return(v, &iter->ucount[type]);
> +               long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
>                 WARN_ON_ONCE(dec < 0);
>                 if (iter == ucounts)
>                         new = dec;
> 
> 
> otherwise,
> 
> inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_NPROC, 1)
> 
> means
> 
> long inc_rlimit_ucounts(struct ucounts *ucounts, UCOUNT_RLIMIT_NPROC, long v)
> {
> 	struct ucounts *iter;
> 	long max = LONG_MAX;
> 	long ret = 0;
> 
> 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
> 		long new = atomic_long_add_return(v, &iter->ucount[UCOUNT_RLIMIT_NPROC]);
> 		if (new < 0 || new > max)
> 			ret = LONG_MAX;
> 		else if (iter == ucounts)
> 			ret = new;
> 		max = get_userns_rlimit_max(iter->ns, UCOUNT_RLIMIT_NPROC);
> 	}
> 	return ret;
> }
> 
> which means that UCOUNT_RLIMIT_NPROC overwrites ucount[UCOUNT_RLIMIT_NPROC]?
> 

-- 
Rgrds, legion

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

[Alexey Gladkov]

On Wed, Jan 12, 2022 at 03:14:45PM +0100, Alexey Gladkov wrote:
> On Wed, Jan 12, 2022 at 03:02:54PM +0100, Christian Brauner wrote:
> > On Wed, Jan 12, 2022 at 02:22:42PM +0100, Anders Roxell wrote:
> > > On Wed, 12 Jan 2022 at 14:18, Christian Brauner
> > > <christian.brauner@ubuntu.com> 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@kernel.org>
> > > > 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@intel.com>
> > > >     Signed-off-by: Alexey Gladkov <legion@kernel.org>
> > > >     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
> > > >     Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> > > >
> > > > 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.
> > 
> > Uhm, doesn't this want to be:
> 
> Yes. I miss it. I tried not to mix the logic, but I myself stepped on this
> problem.

It should be fixed in the four places:

diff --git a/kernel/ucount.c b/kernel/ucount.c
index 22070f004e97..5c373a453f43 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -264,7 +264,7 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
 	long ret = 0;
 
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		long new = atomic_long_add_return(v, &iter->ucount[type]);
+		long new = atomic_long_add_return(v, &iter->rlimit[type]);
 		if (new < 0 || new > max)
 			ret = LONG_MAX;
 		else if (iter == ucounts)
@@ -279,7 +279,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
 	struct ucounts *iter;
 	long new = -1; /* Silence compiler warning */
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		long dec = atomic_long_sub_return(v, &iter->ucount[type]);
+		long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
 		WARN_ON_ONCE(dec < 0);
 		if (iter == ucounts)
 			new = dec;
@@ -292,7 +292,7 @@ static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
 {
 	struct ucounts *iter, *next;
 	for (iter = ucounts; iter != last; iter = next) {
-		long dec = atomic_long_sub_return(1, &iter->ucount[type]);
+		long dec = atomic_long_sub_return(1, &iter->rlimit[type]);
 		WARN_ON_ONCE(dec < 0);
 		next = iter->ns->ucounts;
 		if (dec == 0)
@@ -313,7 +313,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
 	long dec, ret = 0;
 
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		long new = atomic_long_add_return(1, &iter->ucount[type]);
+		long new = atomic_long_add_return(1, &iter->rlimit[type]);
 		if (new < 0 || new > max)
 			goto unwind;
 		if (iter == ucounts)
@@ -330,7 +330,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
 	}
 	return ret;
 dec_unwind:
-	dec = atomic_long_sub_return(1, &iter->ucount[type]);
+	dec = atomic_long_sub_return(1, &iter->rlimit[type]);
 	WARN_ON_ONCE(dec < 0);
 unwind:
 	do_dec_rlimit_put_ucounts(ucounts, iter, type);

-- 
Rgrds, legion

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

[Anders Roxell]

On Wed, 12 Jan 2022 at 15:28, Alexey Gladkov <legion@kernel.org> wrote:
>
> On Wed, Jan 12, 2022 at 03:14:45PM +0100, Alexey Gladkov wrote:
> > On Wed, Jan 12, 2022 at 03:02:54PM +0100, Christian Brauner wrote:
> > > On Wed, Jan 12, 2022 at 02:22:42PM +0100, Anders Roxell wrote:
> > > > On Wed, 12 Jan 2022 at 14:18, Christian Brauner
> > > > <christian.brauner@ubuntu.com> 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@kernel.org>
> > > > > 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@intel.com>
> > > > >     Signed-off-by: Alexey Gladkov <legion@kernel.org>
> > > > >     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
> > > > >     Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> > > > >
> > > > > 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.
> > >
> > > Uhm, doesn't this want to be:
> >
> > Yes. I miss it. I tried not to mix the logic, but I myself stepped on this
> > problem.
>
> It should be fixed in the four places:
>
> diff --git a/kernel/ucount.c b/kernel/ucount.c
> index 22070f004e97..5c373a453f43 100644
> --- a/kernel/ucount.c
> +++ b/kernel/ucount.c
> @@ -264,7 +264,7 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
>         long ret = 0;
>
>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
> -               long new = atomic_long_add_return(v, &iter->ucount[type]);
> +               long new = atomic_long_add_return(v, &iter->rlimit[type]);
>                 if (new < 0 || new > max)
>                         ret = LONG_MAX;
>                 else if (iter == ucounts)
> @@ -279,7 +279,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
>         struct ucounts *iter;
>         long new = -1; /* Silence compiler warning */
>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
> -               long dec = atomic_long_sub_return(v, &iter->ucount[type]);
> +               long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
>                 WARN_ON_ONCE(dec < 0);
>                 if (iter == ucounts)
>                         new = dec;
> @@ -292,7 +292,7 @@ static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
>  {
>         struct ucounts *iter, *next;
>         for (iter = ucounts; iter != last; iter = next) {
> -               long dec = atomic_long_sub_return(1, &iter->ucount[type]);
> +               long dec = atomic_long_sub_return(1, &iter->rlimit[type]);
>                 WARN_ON_ONCE(dec < 0);
>                 next = iter->ns->ucounts;
>                 if (dec == 0)
> @@ -313,7 +313,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
>         long dec, ret = 0;
>
>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
> -               long new = atomic_long_add_return(1, &iter->ucount[type]);
> +               long new = atomic_long_add_return(1, &iter->rlimit[type]);
>                 if (new < 0 || new > max)
>                         goto unwind;
>                 if (iter == ucounts)
> @@ -330,7 +330,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
>         }
>         return ret;
>  dec_unwind:
> -       dec = atomic_long_sub_return(1, &iter->ucount[type]);
> +       dec = atomic_long_sub_return(1, &iter->rlimit[type]);
>         WARN_ON_ONCE(dec < 0);
>  unwind:
>         do_dec_rlimit_put_ucounts(ucounts, iter, type);
>

Thank you for the fix.
I applied this patch and built and ran it in qemu for arm64 and x86.
'./runltp -s getxattr05' passed on both architectures.

Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>


Cheers,
Anders

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

[Eric W. Biederman]

Anders Roxell <anders.roxell@linaro.org> writes:

> On Wed, 12 Jan 2022 at 15:28, Alexey Gladkov <legion@kernel.org> wrote:
>>
>> On Wed, Jan 12, 2022 at 03:14:45PM +0100, Alexey Gladkov wrote:
>> > On Wed, Jan 12, 2022 at 03:02:54PM +0100, Christian Brauner wrote:
>> > > On Wed, Jan 12, 2022 at 02:22:42PM +0100, Anders Roxell wrote:
>> > > > On Wed, 12 Jan 2022 at 14:18, Christian Brauner
>> > > > <christian.brauner@ubuntu.com> 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@kernel.org>
>> > > > > 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@intel.com>
>> > > > >     Signed-off-by: Alexey Gladkov <legion@kernel.org>
>> > > > >     Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org
>> > > > >     Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>> > > > >
>> > > > > 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.
>> > >
>> > > Uhm, doesn't this want to be:
>> >
>> > Yes. I miss it. I tried not to mix the logic, but I myself stepped on this
>> > problem.
>>
>> It should be fixed in the four places:
>>
>> diff --git a/kernel/ucount.c b/kernel/ucount.c
>> index 22070f004e97..5c373a453f43 100644
>> --- a/kernel/ucount.c
>> +++ b/kernel/ucount.c
>> @@ -264,7 +264,7 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
>>         long ret = 0;
>>
>>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
>> -               long new = atomic_long_add_return(v, &iter->ucount[type]);
>> +               long new = atomic_long_add_return(v, &iter->rlimit[type]);
>>                 if (new < 0 || new > max)
>>                         ret = LONG_MAX;
>>                 else if (iter == ucounts)
>> @@ -279,7 +279,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
>>         struct ucounts *iter;
>>         long new = -1; /* Silence compiler warning */
>>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
>> -               long dec = atomic_long_sub_return(v, &iter->ucount[type]);
>> +               long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
>>                 WARN_ON_ONCE(dec < 0);
>>                 if (iter == ucounts)
>>                         new = dec;
>> @@ -292,7 +292,7 @@ static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
>>  {
>>         struct ucounts *iter, *next;
>>         for (iter = ucounts; iter != last; iter = next) {
>> -               long dec = atomic_long_sub_return(1, &iter->ucount[type]);
>> +               long dec = atomic_long_sub_return(1, &iter->rlimit[type]);
>>                 WARN_ON_ONCE(dec < 0);
>>                 next = iter->ns->ucounts;
>>                 if (dec == 0)
>> @@ -313,7 +313,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
>>         long dec, ret = 0;
>>
>>         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
>> -               long new = atomic_long_add_return(1, &iter->ucount[type]);
>> +               long new = atomic_long_add_return(1, &iter->rlimit[type]);
>>                 if (new < 0 || new > max)
>>                         goto unwind;
>>                 if (iter == ucounts)
>> @@ -330,7 +330,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
>>         }
>>         return ret;
>>  dec_unwind:
>> -       dec = atomic_long_sub_return(1, &iter->ucount[type]);
>> +       dec = atomic_long_sub_return(1, &iter->rlimit[type]);
>>         WARN_ON_ONCE(dec < 0);
>>  unwind:
>>         do_dec_rlimit_put_ucounts(ucounts, iter, type);
>>
>
> Thank you for the fix.
> I applied this patch and built and ran it in qemu for arm64 and x86.
> './runltp -s getxattr05' passed on both architectures.
>
> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>

Thank you all.

For now I have dropped this from linux-next.  I will add the fix and
will aim to get this cleanup in the next merge window.

Eric