#12060 NORM 4-softw: XO-4 - FS corruption and hangs under memory pressure

[Zarro Boogs per Child]

#12060: XO-4 - FS corruption and hangs under memory pressure
---------------------------------------+------------------------------------
           Reporter:  martin.langhoff  |       Owner:  cjb          
               Type:  defect           |      Status:  new          
           Priority:  normal           |   Milestone:  4-software   
          Component:  not assigned     |     Version:  not specified
         Resolution:                   |    Keywords:               
        Next_action:  never set        |    Verified:  0            
Deployment_affected:                   |   Blockedby:               
           Blocking:                   |  
---------------------------------------+------------------------------------

Comment(by martin.langhoff):

 Steps to repro

 {{{
 mkdir -p /bigtmp
 mount -t tmpfs -o rw,size=1024M none /bigtmp
 mount -o remount,sync /
 # sometimes might need a slightly larger allocation like 160
 dd if=/dev/urandom of=/bigtmp/blob bs=1M count=140
 # this dd command will not complete
 dd if=/dev/urandom of=/blab bs=1M count=16
 }}}

 To find exactly where it hangs...
 {{{

 mkdir -p /bigtmp
 mount -t tmpfs -o rw,size=1024M none /bigtmp
 mount -o remount,sync /

 N=130
 while /bin/true ; do
     if [ -e /bigtmp/blob ]; then
         rm /bigtmp/blob
     fi
     if [ -e /blab ]; then
         rm /blab
     fi
     echo Writing /bigtmp/blob $N MB
     dd if=/dev/urandom of=/bigtmp/blob bs=1M count=$N
     echo Writing /blab 16 MB
     dd if=/dev/urandom of=/blab bs=1M count=16
     N=$(( $N + 1 ))

 done
 }}}

-- 
Ticket URL: <http://dev.laptop.org/ticket/12060#comment:2>
One Laptop Per Child <http://laptop.org/>
OLPC bug tracking system