On Thu, Feb 07, 2013 at 02:15:02PM -0800, Andrew Morton wrote:
> On Thu, 7 Feb 2013 16:57:42 -0500
> Josh Boyer <jwbo...@redhat.com> wrote:
>
> > Hi All,
> >
> > We've hit a weird error in Fedora using the 3.8-rcX kernels. It seems
> > the mock tool is getting back ENOMEM when doing very simple things that
> > normally just work. The 3.7 kernels on the same userspace work just
> > fine. It seems just running 'mock init -v' is enough to cause the
> > failure.
>
> I assume you're not seeing the "page allocation failure" message and
> backtrace. This means that either
Right. If I disable our debug options, I see no backtraces at all and
the python app still gets ENOMEM returned. (See below for those
interested).
> a) it's a __GFP_NOWARN callsite. This is rare. Or
>
> b) it's actually a different error but someone went and overwrote a
> callee's return value with -ENOMEM. We do this a lot and it sucks.
We do it in copy_io :\.
> > At first glance it seems copy_io is failing (possibly because
> > get_task_io_context fails), and then the above fallout is printed. The
> > warning seems fairly valid, but I don't think that is the root of the
> > problem.
>
> yes, get_task_io_context() might be the place. Tried adding a few
> error-path printks in there to see what's happening?
Yeah, that's my next step. I guess I know what I'll be doing tomorrow.
> I can't see anything around there which leaves interrupts disabled
> though. It's quite likely that there's some code with is forgetting to
> reenable interrupts on a rarely-tested error path, and that ENOMEM is
> tickling the bug.
Right, agreed. As I said, I think that is mostly a secondary issue.
Hopefully it will be easy to fix once we figure out why we're getting
the ENOMEM error.
Python backtrace below. Seems to be failing on forking a umount command
after init'ing the chroot. I can put the full output somewhere if
people are interested.
josh
DEBUG: Executing command: ['/bin/umount', '-n', '-l',
'/var/lib/mock/fedora-16-x86_64/root/proc'] with env {'LANG': 'en_US.utf8',
'TERM': 'vt100', 'SHELL': '/bin/bash', 'HOSTNAME': 'mock', 'HOME': '/builddir',
'PATH': '/usr/bin:/bin:/usr/sbin:/sbin'}
Traceback (most recent call last):
File "/usr/sbin/mock", line 539, in <module>
def do_buildsrpm(config_opts, chroot, options, args):
File "/usr/sbin/mock", line 782, in main
chroot.init()
File "<peak.util.decorators.rewrap wrapping mockbuild.backend.init at
0x00D59320>", line 3, in init
File "/usr/lib/python2.7/site-packages/mockbuild/trace_decorator.py", line
70, in trace
result = func(*args, **kw)
File "/usr/lib/python2.7/site-packages/mockbuild/backend.py", line 279, in
init
self._init()
File "<peak.util.decorators.rewrap wrapping mockbuild.backend._init at
0x00D596E0>", line 3, in _init
File "/usr/lib/python2.7/site-packages/mockbuild/trace_decorator.py", line
70, in trace
result = func(*args, **kw)
File "/usr/lib/python2.7/site-packages/mockbuild/backend.py", line 425, in
_init
self._umountall()
File "<peak.util.decorators.rewrap wrapping mockbuild.backend._umountall at
0x00D5C320>", line 3, in _umountall
File "/usr/lib/python2.7/site-packages/mockbuild/trace_decorator.py", line
70, in trace
result = func(*args, **kw)
File "/usr/lib/python2.7/site-packages/mockbuild/backend.py", line 872, in
_umountall
self.mounts.umountall(nowarn=nowarn)
File "<peak.util.decorators.rewrap wrapping mockbuild.mounts.umountall at
0x00D43398>", line 3, in umountall
File "/usr/lib/python2.7/site-packages/mockbuild/trace_decorator.py", line
70, in trace
result = func(*args, **kw)
File "/usr/lib/python2.7/site-packages/mockbuild/mounts.py", line 133, in
umountall
m.umount()
File "<peak.util.decorators.rewrap wrapping mockbuild.mounts.umount at
0x00D4EC08>", line 3, in umount
File "/usr/lib/python2.7/site-packages/mockbuild/trace_decorator.py", line
70, in trace
result = func(*args, **kw)
File "/usr/lib/python2.7/site-packages/mockbuild/mounts.py", line 69, in
umount
mockbuild.util.do(cmd)
File "<peak.util.decorators.rewrap wrapping mockbuild.util.do at
0x00D47140>", line 3, in do
File "/usr/lib/python2.7/site-packages/mockbuild/trace_decorator.py", line
70, in trace
result = func(*args, **kw)
File "/usr/lib/python2.7/site-packages/mockbuild/util.py", line 323, in do
preexec_fn = preexec,
File "/usr/lib64/python2.7/subprocess.py", line 679, in __init__
errread, errwrite)
File "/usr/lib64/python2.7/subprocess.py", line 1143, in _execute_child
self.pid = os.fork()
OSError: [Errno 12] Cannot allocate memory
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