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@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. > > 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
