Bug#523039: /boot/vmlinuz-2.6.26-1-686: umount -f /net/tesla/foo & umount -l -f /net/tesla/foo breaks the whole VFS
Package: linux-image-2.6.26-1-686
Version: 2.6.26-13lenny2
Severity: normal
File: /boot/vmlinuz-2.6.26-1-686
I'm not sure how reproducible this is. I use the automounter to
automount /net/tesla/whatever, and so on. I think I got NFS confused
by changing the exports on tesla without unmounting from llama first.
Anyway, I was in one of those nfs-is-stuck-and-I-need-to-umount
situations.
I ran
sudo umount -f /net/tesla/usr &
sudo umount -f /net/tesla/home &
sudo umount -f /net/tesla/var/tmp &
At least one of these mounts shouldn't have had any open files, but I
wasn't able to check for sure because lsof blocks on broken NFS mounts.
When none of those umounts exitted for several minutes, I ran
sudo umount -l -f /net/tesla/var/tmp &
sudo umount -l -f /net/tesla/usr &
Within seconds of doing that, _local_ file access started to break.
Anything I tried to run hung. e.g. ls didn't return. (I was CDed
to a directory in /mnt/large, an ext3 filesystem on a local disk.)
The machine wasn't totally locked, though. I was able to fg a vi
process, and have it prompt that a file on disk was newer, and then
exit cleanly (and this was over SSH). So user-space (and apparently
even the VFS) wasn't entirely screwed, but there were major problems.
I eventually had to alt+sysrq s, u, b to reboot.
Does umount -l need to check if there's already a umount attempt
going on? The only thing out of the ordinary that I did was
umount -l -f while a umount -f was stuck on the same filesystem.
Machine hardware: PIII 500MHz, 440BX chipset, 512MB. tulip NICs.
This HW has been stable for ~10 years. :)
-- Package-specific info:
** Version:
Linux version 2.6.26-1-686 (Debian 2.6.26-13lenny2) (dannf@debian.org) (gcc version 4.1.3 20080704 (prerelease) (Debian 4.1.2-25)) #1 SMP Fri Mar 13 18:08:45 UTC 2009
** Command line:
root=/dev/md0 lapic ro
** Not tainted
** Loaded modules:
Module Size Used by
autofs4 16420 1
nfsd 186704 17
auth_rpcgss 33952 1 nfsd
exportfs 3904 1 nfsd
nfs 213896 5
lockd 54248 2 nfsd,nfs
nfs_acl 2912 2 nfsd,nfs
sunrpc 162144 26 nfsd,auth_rpcgss,nfs,lockd,nfs_acl
ipt_REJECT 2784 1
xt_tcpudp 2816 16
xt_state 2016 1
nf_nat_irc 2080 0
nf_conntrack_irc 5124 1 nf_nat_irc
nf_conntrack_ftp 6852 0
ipt_MASQUERADE 2592 1
iptable_nat 4680 1
nf_nat 15576 3 nf_nat_irc,ipt_MASQUERADE,iptable_nat
nf_conntrack_ipv4 12268 4 iptable_nat,nf_nat
nf_conntrack 55508 8 xt_state,nf_nat_irc,nf_conntrack_irc,nf_conntrack_ftp,ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4
iptable_filter 2624 1
ip_tables 10160 2 iptable_nat,iptable_filter
x_tables 13284 6 ipt_REJECT,xt_tcpudp,xt_state,ipt_MASQUERADE,iptable_nat,ip_tables
dm_snapshot 14340 0
dm_mirror 15104 0
dm_log 8452 1 dm_mirror
dm_mod 46184 3 dm_snapshot,dm_mirror,dm_log
ipv6 235300 26
button 6096 0
serio_raw 4740 0
snd_pcm 62596 0
psmouse 32336 0
i2c_piix4 7216 0
snd_timer 17800 1 snd_pcm
i2c_core 19828 1 i2c_piix4
snd 45604 2 snd_pcm,snd_timer
soundcore 6368 1 snd
shpchp 25528 0
pci_hotplug 23460 1 shpchp
snd_page_alloc 7816 1 snd_pcm
intel_agp 22332 1
agpgart 28776 1 intel_agp
pcspkr 2432 0
evdev 8000 0
ext3 105512 4
jbd 39444 1 ext3
mbcache 7108 1 ext3
raid1 18016 3
md_mod 67036 4 raid1
usbhid 35904 1
hid 33184 1 usbhid
ff_memless 4392 1 usbhid
ide_disk 10496 10
ata_generic 4676 0
libata 140384 1 ata_generic
scsi_mod 129356 1 libata
dock 8304 1 libata
uhci_hcd 18672 0
piix 6568 0 [permanent]
ide_pci_generic 3908 0 [permanent]
tulip 44064 0
usbcore 118160 4 usbhid,uhci_hcd
ide_core 96168 3 ide_disk,piix,ide_pci_generic
thermal 15228 0
processor 32576 2 thermal
fan 4164 0
thermal_sys 10856 3 thermal,processor,fan
-- System Information:
Debian Release: 5.0
APT prefers stable
APT policy: (990, 'stable')
Architecture: i386 (i686)
Kernel: Linux 2.6.26-1-686 (SMP w/1 CPU core)
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/bash
Versions of packages linux-image-2.6.26-1-686 depends on:
ii debconf [debconf-2.0] 1.5.24 Debian configuration management sy
ii initramfs-tools [linux-initra 0.92o tools for generating an initramfs
ii module-init-tools 3.4-1 tools for managing Linux kernel mo
Versions of packages linux-image-2.6.26-1-686 recommends:
ii libc6-i686 2.7-18 GNU C Library: Shared libraries [i
Versions of packages linux-image-2.6.26-1-686 suggests:
ii grub 0.97-47lenny2 GRand Unified Bootloader (Legacy v
pn linux-doc-2.6.26 <none> (no description available)
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