From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= <toralf.foerster-Mmb7MZpHnFY@public.gmane.org>
Subject: Re: Issues with a rather unusual configured NFS server
Date: Sun, 22 Sep 2013 18:58:29 +0200
Message-ID: <523F21B5.2050305@gmx.de>
References: <52075E01.7030506@gmx.de> <20130812143640.GF4596@quack.suse.cz> <20130813215313.GH17781@fieldses.org> <20130827180655.GE14809@fieldses.org> <521E318C.7040401@gmx.de> <522B9010.8070902@gmx.de> <20130910140937.GD16011@fieldses.org>
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Cc: Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>,
	Linux NFS mailing list <linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"user-mode-linux-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org"
	<user-mode-linux-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>,
	linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Linux Kernel <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"J. Bruce Fields" <bfields-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: "J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
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On 09/10/2013 04:09 PM, J. Bruce Fields wrote:
> On Sat, Sep 07, 2013 at 10:44:00PM +0200, Toralf F=C3=B6rster wrote:
>> Today I run latest git tree with a patched UML (this patch + one for=
 xterm issues) and got 2 times a core dump
>> when I fuzzy test an UML machine with a nearly identical scenario as=
 already described but just shutdowned
>> both UML images instead of shooting one of it in the head.
>=20
> This is a slightly different test case, so for now it sounds like thi=
s
> could be a preexisting problem, not a regression?
>=20
Yes, pre-existing. I'm trying to bisect it, the issue is already in 7d3=
107d.

But every attempt to get the first bad commit before that commit id
failed till now. I started many attempts between v3.10 and 7d3107d. I
could not reproduce that issue 100% in that interval. In that interval
either all tested commits doesn't show the issue or the NFS client hang=
s
during the stop of NFS service infinitely - and counting that as a "bad=
"
commit doesn't work.

=46WIW a single test case currently takes 2 1/2 hour and even then I do
not fully trust the result  (except for a bad commit, that's clear.


> --b.
>=20
>>
>> I'll probably need time to figure out a test case, but just as a pre=
-info here's the back trace:
>>
>> tfoerste@n22 ~ $ gdb --core=3D/mnt/ramdisk/core /usr/local/bin/linux=
-v3.11-7550-g768c9d3 -n -batch -ex bt
>>
>> warning: core file may not match specified executable file.
>> [New LWP 7470]
>> [New LWP 7479]
>> [New LWP 7477]
>> [New LWP 7478]
>> Core was generated by `/usr/local/bin/linux-v3.11-7550-g768c9d3 earl=
yprintk ubda=3D/home/tfoerste/virtua'.
>> Program terminated with signal 6, Aborted.
>> #0  0xb77be424 in __kernel_vsyscall ()
>> #0  0xb77be424 in __kernel_vsyscall ()
>> #1  0x083aada5 in kill ()
>> #2  0x0807163d in uml_abort () at arch/um/os-Linux/util.c:93
>> #3  0x08071925 in os_dump_core () at arch/um/os-Linux/util.c:138
>> #4  0x080613a7 in panic_exit (self=3D0x85b1518 <panic_exit_notifier>=
, unused1=3D0, unused2=3D0x85e76e0 <buf.15920>) at arch/um/kernel/um_ar=
ch.c:240
>> #5  0x0809a398 in notifier_call_chain (nl=3D0x0, val=3D0, v=3D0x85e7=
6e0 <buf.15920>, nr_to_call=3D-2, nr_calls=3D0x0) at kernel/notifier.c:=
93
>> #6  0x0809a4e3 in __atomic_notifier_call_chain (nr_calls=3D<optimize=
d out>, nr_to_call=3D<optimized out>, v=3D<optimized out>, val=3D<optim=
ized out>, nh=3D<optimized out>) at kernel/notifier.c:182
>> #7  atomic_notifier_call_chain (nh=3D0x85e76c4 <panic_notifier_list>=
, val=3D0, v=3D0x85e76e0 <buf.15920>) at kernel/notifier.c:191
>> #8  0x08408628 in panic (fmt=3D0x0) at kernel/panic.c:128
>> #9  0x081131c9 in shrink_dcache_for_umount_subtree (dentry=3D0x42802=
8f0) at fs/dcache.c:941
>> #10 0x08113948 in shrink_dcache_for_umount (sb=3D0x463b8000) at fs/d=
cache.c:1002
>> #11 0x08101677 in generic_shutdown_super (sb=3D0x463b8000) at fs/sup=
er.c:404
>> #12 0x08102395 in kill_anon_super (sb=3D0x0) at fs/super.c:875
>> #13 0x081d3ff8 in nfs_kill_super (s=3D0x0) at fs/nfs/super.c:2598
>> #14 0x0810153a in deactivate_locked_super (s=3D0x463b8000) at fs/sup=
er.c:294
>> #15 0x081015d1 in deactivate_super (s=3D0x463b8000) at fs/super.c:31=
9
>> #16 0x08119c0c in mntfree (mnt=3D<optimized out>) at fs/namespace.c:=
891
>> #17 mntput_no_expire (mnt=3D0x0) at fs/namespace.c:929
>> #18 0x0811b195 in SYSC_umount (flags=3D<optimized out>, name=3D<opti=
mized out>) at fs/namespace.c:1335
>> #19 SyS_umount (name=3D134633856, flags=3D2) at fs/namespace.c:1305
>> #20 0x080618e2 in handle_syscall (r=3D0x498be5d4) at arch/um/kernel/=
skas/syscall.c:35
>> #21 0x08073c0d in handle_trap (local_using_sysemu=3D<optimized out>,=
 regs=3D<optimized out>, pid=3D<optimized out>) at arch/um/os-Linux/ska=
s/process.c:198
>> #22 userspace (regs=3D0x498be5d4) at arch/um/os-Linux/skas/process.c=
:431
>> #23 0x0805e65c in fork_handler () at arch/um/kernel/process.c:160
>> #24 0x00000000 in ?? ()
>>
>>
>>
>> --=20
>> MfG/Sincerely
>> Toralf F=C3=B6rster
>> pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
>=20


--=20
MfG/Sincerely
Toralf F=C3=B6rster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
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