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);