[Xen-devel] recursive error in xen-hotplug-common.sh

[Olaf Hering <olaf@xxxxxxxxx>]

Current xen-unstable does not have backend/vbd/1/768/params for some
reason.  This causes xenstore_read() in xen-hotplug-common.sh to call
fatal().  fatal() calls xenstore_write(). If xenstore-write happens to
fail, fatal() is called once again. Now the block script is busy.

I have added the set -x output, preceded by the env and set output:

SUBSYSTEM=xen-backend
XENBUS_TYPE=vbd
DEVPATH=/devices/xen-backend/vbd-1-768
ACTION=add
PWD=/
UDEV_LOG=3
XENBUS_PATH=backend/vbd/1/768
UDEVD_EVENT=1
XENBUS_BASE_PATH=backend
SHLVL=1
SEQNUM=1478
_=/usr/bin/env

ACTION=add
BASH=/bin/bash
BASH_ARGC=([0]="1")
BASH_ARGV=([0]="add")
BASH_LINENO=([0]="0")
BASH_SOURCE=([0]="/etc/xen/scripts/block")
BASH_VERSINFO=([0]="3" [1]="2" [2]="51" [3]="1" [4]="release" 
[5]="x86_64-suse-linux-gnu")
BASH_VERSION='3.2.51(1)-release'
DEVPATH=/devices/xen-backend/vbd-1-768
DIRSTACK=()
EUID=0
GROUPS=()
HOSTNAME=stein-schneider
HOSTTYPE=x86_64
IFS=$' \t\n'
MACHTYPE=x86_64-suse-linux-gnu
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:.
PIPESTATUS=([0]="0")
PPID=5717
PS4='+ '
PWD=/
SEQNUM=1478
SHELL=/bin/bash
SHELLOPTS=braceexpand:hashall:interactive-comments
SHLVL=1
SUBSYSTEM=xen-backend
TERM=dumb
UDEVD_EVENT=1
UDEV_LOG=3
UID=0
XENBUS_BASE_PATH=backend
XENBUS_PATH=backend/vbd/1/768
XENBUS_TYPE=vbd
_=echo

++ dirname /etc/xen/scripts/block
+ dir=/etc/xen/scripts
+ . /etc/xen/scripts/block-common.sh
+++ dirname /etc/xen/scripts/block
++ dir=/etc/xen/scripts
++ . /etc/xen/scripts/xen-hotplug-common.sh
++++ dirname /etc/xen/scripts/block
+++ dir=/etc/xen/scripts
+++ . /etc/xen/scripts/hotplugpath.sh
++++ SBINDIR=/usr/sbin
++++ BINDIR=/usr/bin
++++ LIBEXEC=/usr/lib/xen/bin
++++ LIBDIR=/usr/lib64
++++ SHAREDIR=/usr/share
++++ PRIVATE_BINDIR=/usr/lib64/xen/bin
++++ XENFIRMWAREDIR=/usr/lib/xen/boot
++++ XEN_CONFIG_DIR=/etc/xen
++++ XEN_SCRIPT_DIR=/etc/xen/scripts
++++ XEN_LOCK_DIR=/var/lock
+++ . /etc/xen/scripts/logging.sh
+++ . /etc/xen/scripts/xen-script-common.sh
++++ set -e
+++ . /etc/xen/scripts/locking.sh
++++ LOCK_SLEEPTIME=1
++++ LOCK_SPINNING_RETRIES=5
++++ LOCK_RETRIES=100
++++ LOCK_BASEDIR=/var/run/xen-hotplug
+++ export 
PATH=/usr/bin:/usr/sbin:/usr/lib/xen/bin:/usr/lib64/xen/bin:/sbin:/bin:/usr/bin:/usr/sbin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:.
+++ 
PATH=/usr/bin:/usr/sbin:/usr/lib/xen/bin:/usr/lib64/xen/bin:/sbin:/bin:/usr/bin:/usr/sbin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:.
+++ export LANG=POSIX
+++ LANG=POSIX
++++ set
++++ grep '^LC_'
++++ cut -d= -f1
+++ unset
+++ trap sigerr ERR
+++ log debug add XENBUS_PATH=backend/vbd/1/768
+++ local level=debug
+++ shift
+++ logger -p daemon.debug -- /etc/xen/scripts/block: add 
XENBUS_PATH=backend/vbd/1/768
++ findCommand add
++ for arg in '"$@"'
++ expr index add =
++ command=add
++ return
++ '[' add '!=' add ']'
++ XENBUS_PATH=backend/vbd/1/768
++ xenstore_read_default backend/vbd/1/768/type MISSING
++ xenstore-read backend/vbd/1/768/type
++ echo MISSING
+ t=MISSING
+ case "$command" in
++ xenstore_read_default backend/vbd/1/768/physical-device MISSING
++ xenstore-read backend/vbd/1/768/physical-device
++ echo MISSING
+ phys=MISSING
+ '[' MISSING '!=' MISSING ']'
+ '[' -n MISSING ']'
++ xenstore_read backend/vbd/1/768/params
+++ xenstore-read backend/vbd/1/768/params
xenstore-read: couldn't read path backend/vbd/1/768/params
+++ true
++ local v=
++ '[' '' '!=' '' ']'
++ fatal 'xenstore-read backend/vbd/1/768/params failed.'
++ xenstore_write backend/vbd/1/768/hotplug-error 'xenstore-read 
backend/vbd/1/768/params failed.' backend/vbd/1/768/hotplug-status error
++ log debug 'Writing backend/vbd/1/768/hotplug-error' 'xenstore-read 
backend/vbd/1/768/params failed.' backend/vbd/1/768/hotplug-status 'error to 
xenstore.'
++ local level=debug
++ shift
++ logger -p daemon.debug -- /etc/xen/scripts/block: 'Writing 
backend/vbd/1/768/hotplug-error' 'xenstore-read backend/vbd/1/768/params 
failed.' backend/vbd/1/768/hotplug-status 'error to xenstore.'
++ xenstore-write backend/vbd/1/768/hotplug-error 'xenstore-read 
backend/vbd/1/768/params failed.' backend/vbd/1/768/hotplug-status error
xenstore-write: could not write path backend/vbd/1/768/hotplug-error
++ fatal 'Writing backend/vbd/1/768/hotplug-error' 'xenstore-read 
backend/vbd/1/768/params failed.' backend/vbd/1/768/hotplug-status 'error to 
xenstore failed.'
++ xenstore_write backend/vbd/1/768/hotplug-error 'Writing 
backend/vbd/1/768/hotplug-error xenstore-read backend/vbd/1/768/params failed. 
backend/vbd/1/768/hotplug-status error to xenstore failed.' 
backend/vbd/1/768/hotplug-status error
++ log debug 'Writing backend/vbd/1/768/hotplug-error' 'Writing 
backend/vbd/1/768/hotplug-error xenstore-read backend/vbd/1/768/params failed. 
backend/vbd/1/768/hotplug-status error to xenstore failed.' 
backend/vbd/1/768/hotplug-status 'error to xenstore.'
++ local level=debug
++ shift
++ logger -p daemon.debug -- /etc/xen/scripts/block: 'Writing 
backend/vbd/1/768/hotplug-error' 'Writing backend/vbd/1/768/hotplug-error 
xenstore-read backend/vbd/1/768/params failed. backend/vbd/1/768/hotplug-status 
error to xenstore failed.' backend/vbd/1/768/hotplug-status 'error to xenstore.'
++ xenstore-write backend/vbd/1/768/hotplug-error 'Writing 
backend/vbd/1/768/hotplug-error xenstore-read backend/vbd/1/768/params failed. 
backend/vbd/1/768/hotplug-status error to xenstore failed.' 
backend/vbd/1/768/hotplug-status error
xenstore-write: could not write path backend/vbd/1/768/hotplug-error
++ fatal 'Writing backend/vbd/1/768/hotplug-error' 'Writing 
backend/vbd/1/768/hotplug-error xenstore-read backend/vbd/1/768/params failed. 
backend/vbd/1/768/hotplug-status error to xenstore failed.' 
backend/vbd/1/768/hotplug-status 'error to xenstore failed.'
++ xenstore_write backend/vbd/1/768/hotplug-error 'Writing 
backend/vbd/1/768/hotplug-error Writing backend/vbd/1/768/hotplug-error 
xenstore-read backend/vbd/1/768/params failed. backend/vbd/1/768/hotplug-status 
error to xenstore failed. backend/vbd/1/768/hotplug-status error to xenstore 
failed.' backend/vbd/1/768/hotplug-status error
++ log debug 'Writing backend/vbd/1/768/hotplug-error' 'Writing 
backend/vbd/1/768/hotplug-error Writing backend/vbd/1/768/hotplug-error 
xenstore-read backend/vbd/1/768/params failed. backend/vbd/1/768/hotplug-status 
error to xenstore failed. backend/vbd/1/768/hotplug-status error to xenstore 
failed.' backend/vbd/1/768/hotplug-status 'error to xenstore.'
++ local level=debug
....



Olaf


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